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Case Scenario: Big Time Toymaker Essay

1. When, if at any point, did the gatherings have an agreement? Our course book characterizes an agreement as â€Å"a guarantee or a lot of guarantees enforceable by law† (). An agreement doesn't really must be recorded as a hard copy. An agreement can be oral and enforceable. Big Time Toymaker and Chou partook in an oral agreement. Big Time Toy Maker and Chou held a gathering where an oral appropriation understanding was reached. Likewise, Big Time Toy sent an email to Chou affirming the understanding. 2. What realities may say something favor of or against Chou as far as the parties’ target purpose to contract? The realities that may say something favor of Chow are the selective arrangement rights for a 90-day duration, the oral understanding that was reached at the gathering and the email he got from Big Time Toy. The realities against Chou would be that there will never be a real composed understanding drafted by Chou. Furthermore, the selective exchange rights understanding specified that no circulation contract existed except if it was recorded as a hard copy. At long last, no composed understanding was turned in inside the first 90-day time frame specified in the selective arrangement right understanding. 3. Does the way that the gatherings were imparting by email have any effect on your investigation in Questions 1 and 2 (above)? Truly, in light of the fact that the email speaks to the affirmation by the two gatherings of the dispersion understanding made in the gathering notwithstanding the email neglecting to make reference to the word â€Å"contract.† furthermore, the headline of the email read â€Å"Strat Deal† and it clarified in detail the value, time allotments, and commitments. Likewise, when Big Time Toy sent a fax to Chow mentioning the draft of the agreement, he faxed it to them right away. 4. What job does the resolution of fakes play in this agreement? â€Å"The rule of extortion is the law administering which agreements must be in writingâ in request to be enforceable† (Melvin, 2010). The job of extortion applies to this situation. The rule of cheats alludes to the prerequisite that particular sorts of agreements be memorialized in a marked composition with adequate substance to prove the agreement. Customarily, the resolution of fakes requires a marked writing in the accompanying conditions. A litigant in a resolution of fakes case who wishes to utilize the Statute as a barrier must raise it in a convenient way. The weight of demonstrating that a composed agreement exists possibly becomes an integral factor when a Statute of Frauds resistance is raised by the respondent. A respondent who concedes the presence of the agreement in his pleadings, having sworn to tell the truth in a testimony or oath, or at preliminary, may not utilize the safeguard under the Uniform Commercial Code (UCC), anyway under custom-based law they m ay even now utilize it.

Managing Social Anxiety Disorder at Work

Managing Social Anxiety Disorder at Work Social Anxiety Disorder Work and School Print Managing Social Anxiety Disorder at Work Social Anxiety Disorder Can Be a Real Issue in the Workplace By Arlin Cuncic Arlin Cuncic, MA, is the author of Therapy in Focus: What to Expect from CBT for Social Anxiety Disorder and 7 Weeks to Reduce Anxiety. Learn about our editorial policy Arlin Cuncic Updated on January 18, 2020 Social Anxiety Disorder Overview Symptoms & Diagnosis Causes Treatment Living With In Children Thomas Barwick/Stone/Getty Images Managing social anxiety disorder (SAD) at work involves recognizing the day-to-day impact of the disorder on your career and identifying solutions. Receiving a diagnosis and entering treatment is the first step toward managing your anxiety symptoms. Telling your employer may also help in that you may receive accommodations to help you better do your job. At the same time, people with SAD may face  specific problems in the workplace, including the inability to network effectively, fear of attending business social events, problems developing relationships with coworkers, lack of self-confidence, and difficulty speaking up in meetings. Bernardo Carducci, Ph.D., a psychology professor at Indiana University, head of the Shyness Research Institute, and author of Shyness: A Bold New Approach and The Pocket Guide to Making Successful Small Talk, argues that when shyness is properly managed, there is no limit to the achievement of shy people in the business world. Carducci points to the success of notably shy Microsoft co-founder Paul Allen, one of the world’s richest and most successful people, and also a shy person. While shyness is not the same as social anxiety disorder, ideas to help shy people adapt to the business world may also be useful for managing social anxiety in the workplaceâ€"particularly if you struggle with social skills. If you are in a competitive workplace and feel that your anxiety is interfering with your career advancement, or if you simply want to feel more comfortable in the workplace, it is worth investing  time in developing a comfort level with the social aspects of your work. Lets consider a number of these areas and how you might cope. Looking for Work If you are new to the workforce or looking for work after a long period of unemployment or time spent in the same job, the prospect of going on job interviews may be intimidating. Although job interviews can be more challenging for those with social anxiety disorder, proper preparation and use of coping strategies can help. For example, you could have a friend conduct a mock interview with you so that you get practice answering questions or engage in deep breathing to calm yourself about the entire process. Tips to Cope With Job Interview Anxiety Job Duties Some aspects of work itself can be challenging for those with social anxiety. For example, if you are in sales, you might find yourself needing to engage in  cold calling clients. You may need to give presentations or speeches as part of your role. It can feel doubly difficult to manage your anxiety when excellent social skills or the ability to perform under pressure are part of your job. However, if you choose a job that suits your interests and personalityâ€"anxiety is an issue that can be worked on. Social skills training (or even reading self-help books about social skills) or groups such as Toastmasters (for public speaking) might be good options to boost your performance at work. Coworkers Networking is an important part of being successful in your career. If you aren’t able to build relationships with the people that you work with, it will be much more difficult to advance at work. In addition, since you spend most of your waking hours at work, wouldn’t you like to have friends there? To become more comfortable with coworkers, constantly strive to expand your comfort zone. Engage in small talk with people whom you see throughout the day, such as in the lunchroom, in the elevator, or at the water cooler. Greet people with general comments or compliments and start brief conversations. Gradually, other people will see that you are the kind of person who is approachable and with whom conversation is easy. Its less important that you say the right thing, and more important that you just keep showing up and being present. People are generally more comfortable around others the more times that they see them. Spotlight Effect: Not Everyone Is Looking at You Speaking to Supervisors Speaking to your supervisor can be challenging if you live with social anxiety disorder. You might agonize over the smallest contact, such as needing to ask a question about your work or clarifying an issue. Unfortunately, avoiding your supervisor in this way can affect your job performance. If you find casually speaking with your supervisor anxiety provoking, see if you can make an appointment. Practice what you are going to say in advance so you have your ideas clear in your head (dont over-practice as this is a safety behavior and counter-productive). If you still find this hard, try communicating in a less threatening way, such as through e-mail. Or, always prepare a list of points when you go into a meeting. Your anxiety will be reduced because you can focus on your notes and you will also come across as more prepared. Finally, gradually work up to asking harder questions. Make a list of things you need to talk to your supervisor about, and then start with the one that feels least anxiety-provoking, such as asking for clarification on some aspect of your work. From there, you can work your way up to harder topics, such as asking for a raise or a promotion. Business Meetings If you feel uncomfortable in meetings, try arriving 10 to 15 minutes early so that you can meet people as they arrive. This is the opposite of what you probably  do now; you likely tend to show up late so that you don’t have to engage in small talk with others in the meeting. However, this will actually make you feel more isolated. During meetings, remember that others also may feel uncomfortable about speaking up. Likely about half the people in your meeting are also nervous about voicing their opinion. Usually, they will be relieved if you are the first to speak and will admire you for doing so. Finally, if you find your anxiety overwhelmingly uncomfortable during meetings, try examining the thoughts that you have while in a meeting. If you usually think, I am terrible in meetings. I always make a fool of myself, ask yourself whether that thought is helpful and realistic. Could you replace it with a more helpful thought? Try something like I am trying hard to do better in meetings or I think most people are okay with how I come across. Even if it feels uncomfortable at first, over time these positive affirmations will help to build your confidence. Tips for Coping With Anxiety in Work Meetings Business Social Functions Depending on your place of employment, there may a variety  of social functions that you are expected to attend: the company picnic, annual holiday party, retirement gatherings, business conferences, or business lunches. Make sure you have something to talk about on these occasions. Read the newspaper, visit an online news source, or read current magazines. In addition, avoid using alcohol to overcome your inhibitions. Often staying in a situation long enough will have the same effect on reducing your inhibitions as drinking alcohol. The next time you are at a social event, have flavored water instead and notice how your anxiety level decreases over time even when you are not drinking alcohol. A Word From Verywell If you continue to struggle with social anxiety at work, consider visiting a therapist who specializes in anxiety disorders. Social anxiety disorder is a mental illness that requires professional intervention for a full recovery.

The Threat Of The United States - 966 Words

We walk amongst each other weaving in and out of eachother’s lives. To our disadvantage, we all wear a distinct expiration date plastered upon our face. As a society, we struggle day to day fighting a battle in which we know the outcome of. To our dismay, time is not the enemy but our very own DNA is the true culprit. Today, we come together as a community to fight for our right at the longest life available. The aisles at our local pharmacies are packed full of rows and rows of anti-aging products that our consumer based culture is haunted by. Over the past century, the search to extend life has blown through the roof. We’ve become so preoccupied with the fear of death that society has tackled great lengths to combat the cycle of life. Much confusion has risen as to where the line falls in regards to what is appropriate and what is unethical. Recent findings have begun to emerge which are attracting light to the many flourishing possibilities that our science and technological advances offers. Numerous attempts are being made in the hopes of finding an answer to the problem of the millennium. The concept of cloning has caught scientists attention throughout this past century. The world has to come to grips that the cloning technology is almost here,† a representative for a European research group, Panos Zavos. Clones are life forms that have identical genetic coding. A clone is an organisms replica. Originating in the late 1880’s; the first record of synthetic embryoShow MoreRelatedThe Threat Of The United States844 Words   |  4 PagesUnited States While not geographically located in the South East Asian region, the US in recent years has implemented a policy referred to as the Asian Pivot. The Asian Pivot is the increase of the US military within the region with the intention to curb the regional monopoly of the Chinese and to offer a quicker response for their South East Asian allies. This balance of power means that the US has an invested interest in the security of the regions. As a key member of the Nuclear ProliferationRead MoreThe Threat Of The United States1213 Words   |  5 Pages A threat is looming over the United States like the dense fog of an early fall morning. It promises total chaos that will leave the population in the dark. Imagine everything that uses electricity, which Americans take for granted, just stopped working. Lights, cell phones, running water, all of these are gone in the blink of an eye. This threat has the potential to bring the United States to a grinding halt with little to no casualtie s, at first. An EMP attack would cripple the United StatesRead MoreThe Threat Of The United States854 Words   |  4 Pagescontrol further. This of great concern to the United States government as ISIL is a direct threat to our interests in the region and to the homeland. They have killed three Americans this year with the possibility of publicly killing the other American hostages they hold. These killings are a direct attack on the United States and cannot be ignored. In addition, there are Americans in their ranks that heighten the threat ISIS poses to the United States. With access to US passports and the abilityRead MoreThe Threat Of The United States1062 Words   |  5 Pages When we hear the word terrorists, we only think of the people trying to destroy the United States. The U.S is used to being admired as being a great country, and when they send troops into other countries and attack them, they expect them not to fight back. However, on September 11, 2001 there was a series of attacks against the United States that left the country in fear. The country was in utter shock and disbelief as they watched four airlines hijacked by suicide bombers take down the World TradeRead MoreThe Dangers Of Threats To The United States1215 Words   |  5 PagesThe United States has many great threats to their security. There are people everyday who would do anything to make sure the US can no longer be the biggest world power. The United States is currently battling some pretty serious threats to their security such as: ISIS, cyber threats, climate change, and nuclear security within other states. Globalization has hugely impacted America’s position in the worl d because of our democracy being the world’s leading superpower and our MNC’s contributing greatlyRead MoreThe Threat Of The United States Army865 Words   |  4 PagesWhile the United States Army is dedicated to promoting peace, stability and security throughout the world, there are challenges that are necessary to address. Russia, North Korea, China, Iran, the rising of non state actors in the Middle East, and future strategic campaigns all present issues that face the Army. Coupled with budget sequestration, these challenges are amplified. Russia is the largest threat facing the United States [25]. The threat from Russia specifically comes from not only theirRead MoreThe United States And The Threat Of Communism1298 Words   |  6 PagesThe United States and the Threat of Communism Over the course of the history of the United States of America, there have been numerous threats from various international countries. And with these numerous threats come different responses from the United States. Such as the French and the British during the 1790s, the U.S. government created the Alien and Sedition Acts The U.S. also had conflict with the British over the territory of Oregon,which ended in the creation Oregon Treaty. Later duringRead MoreThe United States Face Challenges And Threats1361 Words   |  6 PagesThe United States face many challenges and threats. The 2014 Quadrennial Homeland Security Review identifies six challenges that pose the most strategically significant risk to the United States over the next five years. These challenges include the terrorist threat, cyber threats, biological concerns, nuclear terrorism, transnational criminal organizations, and natural hazards (Department of Homeland Security, 2014). Of these six challenges, the terrorism t hreat seems to create the biggest fearRead MoreEssay on United States Threat Analysis2382 Words   |  10 PagesAbu Sayyaf is still a big threat to the United States, it has roughly 200-500 members based out of the southern Philippines. Here in the United States the FBI is still tracking 3 of the main organizers of the Abu Sayyaf organization and the organization has made comments that have stated they want to fight the United States and it is strongly believed that given the opportunity although they are a small organization they will in fact take a huge leap at harming American citizens by means of bombingRead MoreForeign Threats And Its Effects On The United States1787 Words   |  8 Pagesmigrations into the United States, citizens developed concern from the fluctuations between economic depression and prosperity and if the nation could afford absorbing than many people (Schaller, Schulzinger, Selfa, Greenwood, Kirk, Purcell, Dean p. 619) Migrations haven’t stopped in the 21st century and today more than ever there is increasing foreign threats because of the negative sentiment many countries have towards US policy. From this ever changing world with higher threat levels what has homeland

Female Pirates - 2921 Words

Female Pirates Kristina A. Paxton (Shaarda) Excelsior College Women have been held to have particular power over the sea. There is an ancient superstition that women are not good for ships. The contradiction between woman as sea power and woman as a sea jinx is hard to understand. Women pirates however rarely brought bad luck to a ship, they were actually very good luck, and their loss to a ship often brought an end to that ships sailing days. The women that sailed the seas came from all walks of life; there were royals such as Queen Teuta of Illyria who sailed in the 200’s B.C., as well as the Irish seafaring clanswoman, Grace O’Malley, who was practically royalty in that culture in the 1500’s. There were also illegitimate daughters†¦show more content†¦After some time sailing she also served as a soldier in both infantry and cavalry units, very often proving braver and more courageous than her fellow soldiers. While serving as a soldier she fell in love with one of her comrades, and found a way to let him know s he was a woman, and shortly thereafter they married. After they were married, Mary and her new husband left the service and set up a restaurant where their former comrades could come and eat. However, not long after they opened the restaurant Mary’s husband died and the war ended, leaving Mary with no spouse, and no income since the soldiers no longer came to eat at the restaurant. She gave up her restaurant and went back into sailing. Eventually the ship she was on sailed to the West Indies where it was captured by pirates, whom she eventually joined. Initially Mary Read had no intentions of becoming a pirate as it was something â€Å"she always abhor’d† (Defoe, 1999, p. 146), and she was not planning on staying on that ship. Her intentions to leave the ship changed when she fell in love with another pirate. Her new love had run into trouble with a much larger pirate than him, fearing the worst for her love, she picked a fight with the same pirate and schedule d him to a duel, killing him two hours before her lover was to fight him. Mary’s life as a pirate came to an end in 1720, when the ship she and her crewmates were captured andShow MoreRelatedGoblin Market and Bloody Chamber1213 Words   |  4 Pagesï » ¿Nicole Broeke Professor C. Brady English 201 4 December 2014 Female Heroism In both Goblin Market and â€Å"The Bloody Chamber†, women face objectification as pornographic objects whose solitary purpose is to be a man’s appealing possession. Evidently, the objectification of women impacted the way each author constructed their texts. Feminist movements aiming to undermine these rigid female and male roles are prominent in the time period of both literary works. Both Christina Rossetti and Angela CarterRead MoreAnalysis of The Pirates of the Caribbean: The Curse of the Black Pearl Poster783 Words   |  4 Pages Design Analysis Essay BCM 110 In this essay I am going to analyse the movie poster for the film ‘Pirates of the Caribbean : The Curse of the Black Pearl’ . This film was released in 2003 directed by Gore Verbinski and it was a huge Box-Office hit and had great reviews . It also made Johnny Depp the superstar he is now and it stars other actors such as Orlando Bloom and Keira Knightley . The genre of the film is an action adventure film with lots of other elements in it . Read MoreA Brief Biography of Keira Knightley1123 Words   |  5 Pagesthe movie was very strong, especially among young female athletes. The film earned a respectable $32.5 million in America. Much of its success was due to the chemistry between Knightley and Nagra, whose believable friendship was at the center of this coming-of-age story. Bend it like Beckham was a big hit, but nothing like what was to come next. Keira beat out 75 other young actresses for the part of Elizabeth Swann in the Disney movie Pirates of the Caribbean: The Curse of the Black Pearl. SheRead MoreThe Origins Of The Gothic Culture1558 Words   |  7 Pagesfashion always being recycles by looking at pirates’ clothing. Gothic fashion can be inspired from different sources like pirates. Pirates were outlaws because of they robbed other ships of their treasures. This made the idea of the pirate’s style of clothing appealing to Goth culture because they want to disconnect from society’s social norms just like the pirates did. In medieval times, pirates typically wore loose shirts that had long sleeves. Pirate style of shirts wornby the Goth culture usesRead MoreYay for Feminism in the 1700s!1265 Words   |  6 PagesAnne Bonny and Mary Read are the two most famous women pirates. Though there were many other female pirates, they arent quite as well known. Each of their stories should be first told s eperatly, in order to efficiently understand their story. Anne Bonny was born illegitimately to a lawyer named William Cormac and the maid under his employ, Mary Brennen somewhere near Cork, Ireland and sometime between 1697 and 1700. When their affair became public he, his mistress, and his new daughterRead MoreGender Roles Peter Pan1247 Words   |  5 PagesGender Roles in Peter Pan J. M. Barrie’s Peter Pan tells the story of â€Å"the boy who never grew up.† Barrie paints Peter as an extraordinary character living in a mystical world called Neverland, flying through the air, and fighting villainous pirates. He is also the boy who takes a young girl named Wendy from England back to Neverland with him. The interaction and interdependence of Barrie’s two characters, Peter and Wendy, symbolize and spread cultural gender stereotypes by mirroring the stereotypesRead MorePeter Pan Reflection1097 Words   |  5 PagesDisney in 1953. It’s about a boy, who goes to see Wendy Darling and her brothers, John and Michael, bringing them to Neverland. They go on many of adventures such as seeing â€Å"The Lost Boys, mermaids, meeting Native American tribes, and a group of pirates lead by Captain Hook. I selected this movie because it is my favorite childhood movie, despite my knowledge of its many faults. It is my favorite movie because I relate t o the kids who never want to grow up; I wish I never had to grow up and couldRead MoreDifferent Times, Different Ideals1267 Words   |  6 Pagesmother-like figure and a harlot. Throughout the novel, all the female characters must either be parental or crave the companionship of a male character, which often results in jealousy. Wendy and Tinker, being the two main female characters of the story, represent these two different types of women acceptable in the Victorian Era. Wendy, who is a mother-like figure to the Lost Boys and a female accomplice for Peter, seems to be the only female character in the novel that is a â€Å"fitting† women of the timeRead MoreThe Impact Of Nazi Policy On The Young People1242 Words   |  5 Pageswere independent groups who were against the Nazi party’s affairs with young people. Illegal youth groups include the Najavo Gang, Kittelbach Pirates, Swing Movement and the Edelweiss Pirates. These groups opposed Nationalist Socialist views and defied the youth movement. The Edelweiss Pirates emerged circa 1930’s and the gang consisted of male and female teenagers of ages 12 to 18 in the work-force and received good pay. They often provoked and beat up members of the Hitler Youth. After receivingRead MoreJohnny Depp: A Truely Unique Actor1341 Words   |  6 Pagesnot have soul, Johnny Depp is truly a one-of-a-kind actor. With a spectrum of characters Depp has played, ranging from Edward Scissorhands in the movie Edward Scissorhands (1990), to playing his role in 21 Jump Street (1987), up until the recent Pirates of the Caribbean (2003), he is involved in roles that â€Å"only the likes of Depp can pull off† (â€Å"Johnny Depp†, 1). Although coming from rebellious teenage years and many â€Å"ups and downs of his personal life† (â€Å"Johnny Depp Biography†, 2), the actor has

Tutankhamun’s Tomb, Egypt Free Essays

Ancient History Preliminary Assessment Task 2013 TRANSCRIPT: TUTANKHAMUN’S TOMB, EGYPT When archaeologist Howard Carter discovered the tomb of Tutankhamun in 1922, he remarked that it was â€Å"the day of days, the most wonderful that I have ever lived through, and certainly one whose like I can never hope to see again. † On that November day, not only had this man uncovered an unknown ancient Egyptian tomb, but one that had lain nearly undisturbed for over 3000 years whose remains laying within astounded the world. Previous excavations in the Valley of the Kings in Egypt by Theodore Davis had found and cleared the tombs of Tutankhamun’s family and their possessions. We will write a custom essay sample on Tutankhamun’s Tomb, Egypt or any similar topic only for you Order Now By 1913, Davis had not yet found an intact royal tomb and became disillusioned, finally declaring the area exhausted of By 1920, the tomb of nearly every New Kingdom king from between 1550 and 1070 BCE had been found in the Valley of the Kings, but Tutankhamun’s remained missing. Lord Carnarvon, an English aristocrat who was enthusiastic about Egyptology, applied for and purchased the license Davis gave up and chose Howard Carter, a British Egyptologist, to continue the search. Minor finds by Davis bearing Tutankhamun’s name led Carter to believe the king was still somewhere in the valley and felt the finds justified a further exploration. Between 1917 and 1921 the two worked in the eastern valley without success. Carter convinced Carnarvon to persist for another season, determined to find Tutankhamun. Carter’s team cleared bedrock using the grid system of archaeological excavation. This technique was developed in WWI for the purpose of maintaining a system that ensured stratigraphic control of excavations in trench digging and artillery barrages. Using these methods, on November 1st 1922 a staircase was uncovered in the limestone cliffs of the Valley of the Kings. The entrance door, which had a dry limestone blocking plastered with gypsum, was later uncovered to reveal Tutankhamun’s name. The entrance they excavated then led to an eight-metre-long corridor that revealed evidence of past robberies. Four small rooms flowed from the entrance and corridor, including an Antechamber, Annexe, Burial Chamber and Treasury. On November 6, Lord Carnarvon was summoned by telegraph and arrived with his daughter, Lady Evelyn Herbert, to watch the excavation process unfold. Compared to tombs of other pharaohs of the time, Tutankhamun’s tomb was small and lacked some of the more elaborate features – for example, tomb paintings and decoration were only found in the Burial Chamber room rather than all rooms. Due to Tutankhamun’s early death, a lack of time was left to prepare his tomb. One of the most remarkable divisions of Tutankhamun’s tomb was that he was the only pharaoh to have been discovered intact in his tomb with the complete burial furniture and possessions surrounding. These objects included gilded statues of Tutankhamun, gods, and family members,. Objects from the king’s daily life were also present such as clothes, furniture and sceptres. Funerary goods such as canopic jars containing the king’s entrails and hundreds of shabtis (which were small statues of people, intended to serve as slaves in the afterlife) were found, along with more personal items. Two miniature coffins containing mummies of stillborn babies were placed beside Tutankhamun’s sarcophagus. These were likely to have been his children by his half-sister and wife, Ankhsenamun, whom he married around the age of ten. It took Carter the most part of ten years to empty all the chambers. This was due to difficulties from a sudden change in protocol and access privileges from both British and Egyptian governments, affecting the excavation on the site and delaying the whole process. It was also due to the meticulous process Carter took in his excavation – each object was recorded, catalogued, described, and photographed in situ, before being preserved and conserved, then finally packed and transported to the Egyptian Museum in Cairo. The main archaeological find of the tomb however, was King Tutankhamun himself. Inside the burial chamber were four gilded shrines, one inside the other. The innermost shrine held a quartzite sarcophagus which in turn held three coffins. The innermost coffin made of solid gold contained the mummy of Tutankhamun, wrapped in linen and wearing his famous gold plated mask, inlaid with blue glaze and inscribed with religious spells. Although the body was found to be poorly preserved, Tutankhamun was notable for being the only Egyptian pharaoh found in situ, intact and unsealed since ancient times in his tomb. In 1925 the body was removed from the coffins with difficulty, due to the abundance of resin that had been poured over the mummy at the funeral. Carter and his team were forced to cut the body in order to remove it from the coffin. Four sessions of scientific analysis were conducted on Tutankhamun’s body over the years. These proved to ablaze many controversial issues and interpretations over Tutankhamun’s cause of death. The first inquiry was an autopsy which began after Carter’s excavation in 1925, carried out by Douglas E. Derry, a Professor of Anatomy at the Egyptian University in Cairo. Derry found Tutankhamun to have a fracture in his lower left thighbone, a large, ragged embalming wound, and estimated his age of death to be between 18 and 22 years. He also reconfirmed the body’s poor preservation, noting that the inner layers of linen were reduced to the ‘consistency of soot’, that an overload of resin destroyed the corpse, and that the nose was heavily flattened by the bandages. The second scientific analysis of the body was conducted by R. G. Harrison in 1968. With an x-ray the team concluded that two bone fragments in the skull and haemorrhaging may have been caused by a blow to the head, and that the body was missing a sternum and some frontal rib bones. This caused speculations about Tutankhamun’s death, some suggesting murder and others suggesting a fatal chariot accident. Examiners also noted that the spine showed signs of scoliosis. A further x-ray and blood analysis in 1978 was led by James E. Harris. It wrongly concluded that the king was perhaps 23 to 27 years old at death. A blood analysis supported the idea that Tutankhamun was related to the body of Akhenaten found in another tomb in the Valley of the Kings – suggesting it was Tutankhamun’s father. A final CT scan in 2005 was conducted to test the conclusions of previous inquiries and to look for additional details still undiscovered. Led by Dr Zahi Hawass, the scan confirmed the previous findings of the king’s height, health, general features and age of death at around 18-19 years. It also disproved the theory of scoliosis, relating the curvature of his spine instead the way his body was arranged by the embalmers. 8MINSThe theory of murder by head trauma and death relating to the missing ribs was also ruled out and blamed on embalmers and/or Carter’s team, The leg trauma found in Tutankhamun’s lower left femur may have introduced infection which may have been fatal. This theory however remains unproven. Facial reconstruction of King Tutankhamun was also commenced using the new CT scan data in 2005. A forensic anthropologist calculated sizes of tissue on his face. A cast was then made of the skull from this data which was used to build a latex model. When the CT scan data and skull cast was given to another forensic team for checking, the skin colour proved to be somewhat controversial in interpretation. Controversies occurred as it is impossible to determine skin colour accurately. This is because there is a large variation on skin tones in the area, and not enough accurate information available as Ancient Egyptian art depicted bodies in unrealistic colours. Thus, no consensus on the King’s skin tone was reached, however the overall results between the different reconstructions was similar. At the time of discovery, very little was known about this ancient pharaoh. Thanks to the efforts put into many investigations over the years and, in particular, the 1923 ‘Curse of King Tut’ phenomena that was spread through media following the untimely death of Lord Carnarvon, knowledge and interest of Tutankhamun has skyrocketed. Tutankhamun’s legacy remains to this day and he continues to stand across the globe as one of the most well-known Egyptian pharaohs in history. ——————————————– [ 1 ]. Carter, H. , Mace, A. C. , The Tomb of Tut-Ankh-Amen: Discovered by the Late Earl of Carnarvon and Howard Carter, Volume 1 (New York: Cambridge University Press, 1923), 94. [ 2 ]. N. Reeves, The Complete Tutankhamun, Thames Hudson, 1990, pp. 116-17 How to cite Tutankhamun’s Tomb, Egypt, Papers

The Scarlet Letter Theme Analysis free essay sample

The Scarlet Letter, a novel written by Nathaniel Hawthorne, is a novel that takes place in the town of Boston, Massachusetts in 1642. Hester Prynne, the main character of the story, commits the sin of adultery. Because of this sin, she is blessed with a child named Pearl. Her punishment is to wear a scarlet letter â€Å"A on her chest for the rest of her life, which affects the way the townspeople look and act around her. Also, she must stand on the scaffold in the town for three hours for the whole town to recognize her grave sins. The man who should be standing upon the scaffold along with her and Pearl is the town minister, Dimmesdale. He is presented as a weak character because of his fear of losing his beloved reputation as such a holy man. The townspeople do not know who Hester’s husband is, but the reader eventually finds out that Hester’s husband is Roger Chillingworth. We will write a custom essay sample on The Scarlet Letter Theme Analysis or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page His quest throughout the novel is to take revenge on Dimmesdale. Many characters, including Pearl, Mistress Hibbins, Chillingworth, and Dimmesdale, are all characters who are associated with evil and the Black Man. Many of the same characters also struggle with their identity within their Puritan society. Because of the main sin of adultery, several themes emerge in the novel; the three major themes that are demonstrated in the lives of the main characters are the positive and negative effects of sin, the nature of evil, and identity issues in society. To begin with, the main sin of adultery brings about the theme of the positive and negative effects of sin. Although, the cause of these effects comes from the same sin of adultery, each character is affected differently. Firstly, Hester becomes a stronger person because of her sin. Obviously, in this case, Hester’s sin affects her positively. The law sentences her to wear a scarlet letter â€Å"A† on her chest for the rest of her life. The initial intention of this scarlet letter is to make the townspeople almost gag every time they see her, but because of Hester’s strength, courage, and pride, she reverses these intentions and by the end of the novel, the scarlet A on her chest represents â€Å"able†. Even the town minister, Dimmesdale knows she is strong. He says, â€Å"Think for me, Hester! Thou art strong. Resolve for me! † (Hawthorne 172). Hester proves that she can still stand for what she believes in without being so rebellious. â€Å"She has managed to show—before the whole assembled population—that it is possible, even for a relatively powerless woman, to stand her ground without pushing her defiance too far† (Evans â€Å"Civil Disobedience†). Even though her society has ruined her reputation, she handles it a mature way. Differently, Dimmesdale is portrayed as a weak character. He is aware of Hester’s strength and believes her strength is what keeps him alive. From the early stages of the novel, the reader soon finds out that Dimmesdale has also committed adultery. His sin has negative effects on him and makes him physically weak and delusional from the very beginning. The author notes, â€Å"About this period, however, the health of Mr. Dimmesdale had evidently begun to fail† (Hawthorne 103). The townspeople see these physical changes in Dimmesdale’s character but they believe it is a result from Dimmesdale’s long hours working on his sermons. They do not know however that, â€Å"In Mr. Dimmesdale’s secret closet, under lock and key, there was a bloody scourge† (Hawthorne 125). The townspeople are completely oblivious to the suffering Dimmesdale is putting on himself. Furthermore, Pearl, Hester’s daughter, is also affected by Hester’s sin in negative ways, considering she is shunned among her peers. â€Å"Pearl was a born outcast of the infantile world† (Hawthorne 79). When the children in town are playing after church or school, Pearl is the one to just watch them while holding her mother’s hand. The children know that there is something different about Pearl from their parents, so they choose to stay away. Lastly, Chillingworth is affected by sin negatively because he becomes an evil and vindictive person. He dedicates his life to revenge. Because of his pure evil, he is even seen as the Black Man. Hester questions, â€Å"Art thou like the Black Man that haunts the forest round about us? † (Hawthorne 65). In the long run, the main sin of adultery effects the main characters in different positive and negative ways. Furthermore, the sin of adultery allows the theme of the nature of evil to emerge throughout the novel. The characters in the novel often associate the Black Man with different people. Generally speaking, the Black Man or the Devil, is the main expression of evil. This Black Man is associated with different characters including Dimmesdale, Chillingworth, Mistress Hibbins, Pearl, and even Hester. Firstly, Pearl associates the Black Man to Dimmesdale. She asks, â€Å"And, mother, he has his hand over his heart! Is It because, when the minister wrote his name in the book, the Black Man set his mark in that place? † (Hawthorne 164). Pearl, for such a young age, notices how strange and suspicious Dimmesdale acts and senses the evil within him. Furthermore, instead of direct associations with the Black Man, Chillingworth goes through physical changes that can be compared to the characteristics of the Black Man. By the end of the novel, he has become an uglier, darker, and more crooked version of his former self from seven years back. His actions can also be compared to those of the Black Man, where his actions are meant to spread evil. â€Å"The fact that he is so intelligent also makes him all the more responsible for the sinful path he chooses to pursue and thus all the more spiritually self-destructive† (Evans â€Å"The Complexities†). As an educated man, Chillingworth chooses to dedicate his life to revenge which in turn hurts his well-being physically and emotionally. Moreover, Mistress Hibbins is a character who openly admits to her associations with the Black Man. She states, â€Å"There will be a merry company in the forest; and I wellnigh promised the Black Man that comely Hester Prynne should make one† (Hawthorne 99). She invites Hester to come with her into the forest to see the Black Man, which confirms her interaction with the Black Man. She is known as the town witch and many of the townspeople associate her with the Devil. On the other hand, Pearl does not choose to be identified with the Devil, but she is born into it. She is seen as a product of sin and evil. She is associated with witchcraft, which has its traces back to the Black Man. Mr. Wilson declares, â€Å"The little baggage hath witchcraft in her, I profess† (Hawthorne 99). Even Mr. Wilson sees evil in the innocent little Pearl. Finally, Hester, or more so, the scarlet letter, is associated with the Black Man. In the beginning of the novel, as Hester is entering the prison, the narrator says, â€Å"It was whispered, by those who peered after her, that the scarlet letter threw a lurid gleam along the dark passage-way of the interior† (Hawthorne 58). This red glow is often interpreted as a mark of the Black Man. Throughout the novel, there is also a confusion about where, in general, evil comes from. There is no evil in Hester and Dimmesdale’s affair, instead, it is found in Chillingworth’s vindictive plan for revenge and Dimmesdale’s weakness. The love that both men are have, is changed by the end of the novel. Chillingworth’s â€Å"love† for Hester is turned into a plot for revenge. Likewise, Pearl, for her young age, is almost correct when she suspects Dimmesdale is the Black Man. Because of his fear of losing his â€Å"holy† reputation, Dimmesdale has lost the love he should have for his own child. His love for his reputation over his own child can be interpreted as evil. All things considered, the nature of evil begins with the Black Man and sin. Again, the main sin of adultery brings out the theme of identity issues within the Puritan society. Hester, Dimmesdale, and Chillingworth are all characters who struggle with their identities in the harsh Puritan societies. The intention of Hester’s punishment with the scarlet letter is meant to change how the townspeople see Hester. Chillingworth tells Hester that â€Å"It was debated whether or no, with safety to the commonweal, yonder scarlet letter might be taken off your bosom† (Hawthorne 147). She responds with distress saying the mark of the scarlet letter on her heart can never be removed. She does not want the townspeople to see her as a weak person who is ashamed of who she is. Hester wants to find who she really is and her identity instead of leaving it all up to the people surrounding her. Hester accepts the fact that her sin did happen and that it is a part of her past. If she spent her life hiding the fact that she committed adultery, she would be hiding a part of herself. The townspeople, like many other societies, have a difficult time looking past the scarlet letter and seeing Hester for who she really is. But, eventually, they do realize how able she is. The author notes,   Ã¢â‚¬Å"They said that it meant Able; so strong was Hester Prynne, with a woman’s strength† (Hawthorne 141). They are a group of stereotypical people, similar to people in today’s society. Such stereotypes may explain the ironic fact that the Puritan community ultimately fails to recognize her unrepentant attitude; they, not Hester, eventually begin ascribing new meanings like ‘Able’ to the scarlet badge that was meant to brand Hester as an adulteress† (â€Å"The Scarlet Letter† 355). Hester, therefore, has little trouble proving to the townspeople how much of a strong person she is, but she achieves her goal and stays true to herself. Differently, Dimmesdale has a tough time proving not only to Hester and Pearl, but to himself, who he really is as a person. Because he is the town minister, he is not just an average human being to the other Puritans. He is a symbol of holiness and an example of the right way to live life. Although these people think all of Dimmesdale’s spectacular sermons and actions reflect his holiness, they are misinterpreting several things. The narrator states, â€Å"In their eyes, the very ground on which he trod was sanctified† (Hawthorne 124). His inspirational sermons are a result of his own mistakes. His weakening physical character is not from long nights of writing sermons, but from the agony his sins bring him. Dimmesdale, unlike Hester, has a very hard time accepting who he is as a person. He doesn’t realize that strength and one’s identity come from accepting what one has done wrong. Dimmesdale, from cherishing his reputation too much, has an identity crisis among his society. â€Å"He cannot surrender an identity which brings him the adulation of his parishioners, the respect and praise of his peers† (Martin 115). In contrast, Chillingworth does not try to accept who he is like Hester and Dimmesdale. In the beginning, Hawthorne reveals that Chillingworth changes his name from Roger Prynne, to Roger Chillingworth. He doesn’t accept the fact that his wife cheated on him. He doesn’t accept who he really is. Although Chillingworth deals with it differently than Hester and Dimmesdale, all three characters face problems with their identity within their communities. In conclusion, Hawthorne makes a point that sin can bring about the good and the bad of people. Sin can have positive or negative effects on a person, it can be associated with the Devil, and can cause identity issues. Similarly to today’s society, the Scarlet Letter shows that sin makes an impact on everyone’s lives. When someone lies to a friend or a parent, they can become paranoid. Or they can see themselves as a bad person. Even though this book took place many years ago, the way humanity acts and thinks hasn’t changed. Almost all people experience the negative and positive effects of their sins. Although many people aren’t seen as evil, there are people who are considered very cruel. Maybe not all the time, but identity issues in today’s society can be traced back to sin. Even though adultery does happen often in this society nowadays, it isn’t the only sin that has the same effects that are   portrayed in The Scarlet Letter. Without these effects, people would not be able to learn their lesson. Maybe these effects of sin, although they may seem tough to get through, are what humanity needs, especially in a society like this one. Nowadays, people are so judgmental and are complete perfectionists. Everyone needs to be that or everyone needs to wear this. With life’s hard obstacles, people become stronger and learn that sin is bad, but at the same time, nobody’s perfect and together, everyone has a chance to become a stronger person through their sins, similarly to the way Hester Prynne handled herself in The Scarlet Letter.

buy custom Wire Tap essay

buy custom Wire Tap essay The Wire Trap Act is a law established to protect people against illegal tapping of the communication by intelligence authorities for prosecution purposes. Initially, Title III, which was contained in the Omnibus Crime Control and Safe Streets Act that was enacted in 1968 covered the wire and oral communication only (United States Department of Justice, 2010). However, this was revised subsequently in 1986 to title I, which included electronic communications too. These laws have several provisions related to trapping on information from a person without his or her knowledge. The laws prohibit interception, use, disclosure, or even procurement of information by any person in the form of either electronic, wire, or oral from another person without his or her authorization. The laws also provide exceptions for any person who is allowed to intercept information in any of the three means, as defined by the Foreign Intelligence Act of 1978. The laws also prohibit the use of any illegally o btained information in court as evidence. Authorization to tap into any oral, electronic, or wire communication is granted by a judicial legalization whereby a judge could issue a legalization warranty of up to 30 days. Roving wire traps or multipoint wiretaps is a tracing technique used to intercept communications from a targeted individual (Lippman, 2010). The law provides that such individuals behave in a manner suggesting that they are seeking to distract surveillance or are evading interception. These forms of surveillance violate citizens' constitutional rights by allowing security agents to intercept information from individuals without permission. In fact, this sounds more of eavesdropping, which is a crime. Any right that has an attachment to privacy is utterly disregarded by such intelligence acts because they probe someone without his or her knowledge. Real evidence refers to the physical material that is brought to court as evidence of a crime committed. This evidence is displayed in the courtroom, and a case is conducted based on what is seen in the courtroom (Buckles, 2003). On the other hand, demonstrative evidence refers to evidence produced in court, in the form of an object or any other representation such as sound, picture, maps, and drawings among others. Real evidence is better because it is easy to verify any claims behind a prosecution basing on the actual or physical evidence. In other words, facts can be established easily using physical evidence other than demonstrative evidence. Buy custom Wire Tap essay

The Great Irish Famine Was a Turning Point in History

The Great Irish Famine Was a Turning Point in History In the early 1800s, the impoverished and rapidly-growing rural population of Ireland had become almost totally dependent on one crop. Only the potato could produce enough food to sustain families farming the tiny plots of land the Irish peasants had been forced onto by British landlords. The lowly potato was an agricultural marvel, but staking the lives of an entire population on it was enormously risky. Sporadic potato crop failures had plagued Ireland in the 1700s and early 1800s. In the mid-1840s, a blight caused by a fungus struck potato plants across all of Ireland. The failure of essentially the entire potato crop for several years led to unprecedented disaster. Both Ireland and America would be changed forever. The Irish Potato Famine The Irish Potato Famine, which in Ireland became known as The Great Hunger, was a turning point in Irish history. It changed Irish society forever, most strikingly by greatly reducing the population. In 1841, Irelands population was more than eight million. It has been estimated that at least one million died of starvation and disease in the late 1840s, and at least another one million immigrated during the famine. Famine hardened resentment toward the British who ruled Ireland. Nationalist movements in Ireland, which had always ended in failure, would now have a powerful new component: sympathetic Irish immigrants living in America. Scientific Causes The botanical cause of the Great Famine was a virulent fungus (Phytophthora infestans), spread by the wind, that first appeared on the leaves of potato plants in September and October of 1845. The diseased plants withered with shocking speed. When the potatoes were dug up for harvest, they were found to be rotting. Poor farmers discovered the potatoes they could normally store and use as provisions for six months had turned inedible. Modern potato farmers spray plants to prevent blight. But in the 1840s, the blight was not well understood, and unfounded theories spread as rumors. Panic set in. The failure of the potato harvest in 1845 was repeated the following year, and again in 1847. Social Causes In the early 1800s, a large part of the Irish population lived as impoverished tenant farmers, generally in debt to British landlords. The need to survive on small plots of rented land created the perilous situation where vast numbers of people depended on the potato crop for survival. Historians have long noted that while Irish peasants were forced to subsist on potatoes, other crops were being grown in Ireland, and food was exported for market in England and elsewhere. Beef cattle raised in Ireland were also exported for English tables. British Government Reaction The response of the British government to the calamity in Ireland has long been a focus of controversy. Government relief efforts were launched, but they were largely ineffective. More modern commentators have noted that economic doctrine in 1840s Britain generally accepted that poor people were bound to suffer and government intervention was not warranted. The issue of English culpability in the catastrophe in Ireland made headlines in the 1990s, during commemorations marking the 150th anniversary of the Great Famine. Britains then-Prime Minister Tony Blair expressed regret over Englands role during commemorations of the 150th anniversary of the famine. The New York Times reported at the time that Mr. Blair stopped short of making a full apology on behalf of his country. Devastation It is impossible to determine precise numbers of the dead from starvation and disease during the Potato Famine. Many victims were buried in mass graves, their names unrecorded. It has been estimated that at least half a million Irish tenants were evicted during the famine years. In some places, particularly in the west of Ireland, entire communities simply ceased to exist. The residents either died, were driven off the land, or chose to find a better life in America. Leaving Ireland Irish immigration to America proceeded at a modest pace in the decades before the Great Famine. It has been estimated that only 5,000 Irish immigrants per year arrived in the United States prior to 1830. The Great Famine increased those numbers astronomically. Documented arrivals during the famine years are well over half a million. It is assumed that many more arrived undocumented, perhaps by landing first in Canada and walking into the United States. By 1850, the population of New York City was said to be 26 percent Irish. An article titled Ireland in America in the New York Times on April 2, 1852, recounted the continuing arrivals: On Sunday last three thousand emigrants arrived at this port. On Monday there were over two thousand. On Tuesday over five thousand arrived. On Wednesday the number was over two thousand. Thus in four days twelve thousand persons were landed for the first time upon American shores. A population greater than that of some of the largest and most flourishing villages of this State was thus added to the City of New York within ninety-six hours. Irish in a New World The flood of Irish into the United States had a profound effect, especially in urban centers where the Irish exerted political influence and got involved in municipal government, most notably in the police and fire departments. In the Civil War, entire regiments were composed of Irish troops, such as those of New Yorks famed Irish Brigade. In 1858, the Irish community in New York City had demonstrated that it was in America to stay. Led by a politically powerful immigrant, Archbishop John Hughes, the Irish began building the largest church in New York City. They called it St. Patricks Cathedral, and it would replace a modest cathedral, also named for Irelands patron saint, in lower Manhattan. Construction was halted during the Civil War, but the enormous cathedral was finally finished in 1878. Thirty years after the Great Famine, the twin spires of St. Patricks dominated the skyline of New York City. And on the docks of lower Manhattan, the Irish kept arriving. Source Ireland in America. The New York TImes, April 2, 1852. Lyall, Sarah. Past as Prologue: Blair Faults Britain in Irish Potato Blight. The New York Times, June 3, 1997.

Technology Plan Assignment Example | Topics and Well Written Essays - 1250 words

Technology Plan - Assignment Example This paper will examine a technology plan for a health care services organization. A health care services organization (HCSO) can function a lot better if it has the right kind of information at its disposal without any wastage of time. Efficiency and effectiveness are two important necessities for the smooth functioning of such an organization. Thus, it would be necessary for a HCSO to have a computer network covering all the terminals inside the building linking their records and data together. A centralized server with direct wireless connectivity with all the nodes would be an idealistic way to provide real-time data from one PC to another without the hassle of paper or wastage of time and human resource. Careful planning can even see a paperless management system being implemented at the Indus Hospital, Pakistan which made the greatest technological advancement in terms of a hospital by adopting to a purely paperless system (Garib, 2008). Truly speaking, such a feat would give an HCSO a competitive advantage in terms of productivity and efficacy. With wireless connectivity instead of wired terminals, the HCSO can also have distributed printers within the organization so as to facilitate the printing of various slips or documents near the customer or the doctor instead of a centralized print server. The use of computerized logs with regards to the number of hours devoted by each doctor or healthcare specialist will give an HCSO the flexibility to focus on its core operations. Such systems work with near field communications devices or RFID tags and perform at extremely impressive perfection rates giving the organization the ease of doing away with manual and troublesome payroll processing systems. Auto-payroll systems are quite the norm and can be easily implemented at an HCSO with slight modifications to suit the scenario. Technological advancements are the light of the day and thus if

The New Deal, specifically the works progress administration Thesis

The New Deal, specifically the works progress administration - Thesis Example Prior to America’s entrance into this particular battle, the economy in the country was once again faltering, unemployment was, and basic infrastructure needs at an all time high1. Roosevelt’s New Deal was certainly making a solid impact in this area, as many people were involved in programs facilitated by the Works Progress Administration, yet the reality was that much more was needed. With social welfare programs being taxed to the max, entrance into the Second World War actually ended up making the Works Progress Administration obsolete, as wartime jobs were created, and numerous families found themselves entering into a time of renewed prosperity. The United States entrance into World War II was a far more effective economic stimulus than the social welfare programs introduced under The New Deal, and was specifically more helpful to the economy in the long term than was the the Works Progress Administration. In a nutshell, the Works Progress Administration was created as a way out of the Great Depression. With millions wallowing in despair, government coffers nearly empty, and businesses shuttering their doors all around the country, President Roosevelt and his closest advisors were charged with the task of rectifying a dire situation before it spiraled even further out of control. Since businesses could no long employ the masses, the thought was that the government could provided much needed temporary assistance to working people in the formed of training for skilled labor positions and then having them build up an infrastructure in the country that was sorely in need of repair2. It was seen as win-win situation for the country and for society. This section will highlight some of the benefits that were achieved during the Works Progress Administration, leading into the inherent problems that seem to always invade upon large social welfare programs in nearly any society. Signed into law via and executive order in 1935, the Works Progress

Rate of Reaction Investigation :: Papers

Rate of Reaction Investigation 2HCL + NA ²S ²O ³ à   + 2NaCL Hydrochloric acid + Sodium thiosulphate à   Sulphur + Sodium chloride + S0 ² + H ²0 + Sulphur dioxide + Water Collision Theory For this experiment we can use the collision theory. Collision theory explains how chemical reactions occur and why rates of reaction differ. When particles collide, they may react. A reaction occurs when particle is facing in the correct direction and the collision has enough energy. If more collisions occur, then the chance of a successful collision is higher. [IMAGE] Aim To investigate the rate of reaction between hydrochloric acid and sodium thiosulphate using variables. Equipment Sodium Thiosulphates Hydrochloric Acid Title marked with a cross - Then we will know when the reaction has taken place. Measuring cylinder - Measure how much of solution you use each time, so it's a fair test. Beaker - Where the reaction will take place Bunsen burner - How the temperature can increase. Tripod - To place the beaker onto. Stopwatch - Measuring how long the reaction takes place. Thermometer - To measure how hot the mixture is. Factors/ Variables Catalyst - A catalyst is a substance which increases the speed of a reaction without being changed or used up in a reaction. The catalysis works by giving the reacting particles something to stick to where they can collide into each other; this increases the number of collisions. Concentration - If the solution is made more concentrated it means there are more particles of reactant between the important particles are more likely. Temperature - When the temperature is increased the particles all move quicker, if they are moving quicker, they are going to have more collisions. We used a thermometer to control this. Particle size/ surface area - As the particle size decreases the surface area increases. The rate of reaction will increase because the acid can attack from different places.

The Flowering Response of the Rice Plant to Photoperiod

The Flowering Response of the Rice Plant to Photoperiod A REVIEW OF THE LITERATURE FOURTH EDITION 1985 Los Banos, Laguna, Philippines Mail Address: P. O. Box 933, Manila, Philippines THE INTERNATIONAL RICE RESEARCH INSTITUTE First printing 1969 Partially revised 1972 Revised 1976 Revised 1985 The International Rice Research Institute (IRRI) was established in 1960 by the Ford and Rockfeller Foundations with the help and approval of the Government of the Philippines. Today IRRI is one of the 13 nonprofit international research and training centers supported by the Consultative Group for International Agricultural Research (CGIAR). The CGIAR is sponsored by the Food and Agriculture Organization (FAO) of the United Nations, the International Bank for Reconstruction and Development (World Bank), and the United Nations Development Programme (UNDP). The CGIAR consists of 50 donor countries, international and regional organizations, and private foundations. IRRI receives support, through the CGIAR, from a number of donors including: the Asian Development Bank, the European Economic Community, the Ford Foundation, the International Development Research Centre, the International Fund for Agricultural Development, the OPEC Special Fund, the Rockefeller Foundation, the United Nations Development Programme, the World Bank, and the international aid agencies of the following governments: Australia, Canada, China, Denmark, France, Federal Republic of Germany, India, Italy, Japan, Mexico, Netherlands, New Zealand, Norway, Philippines, Saudi Arabia, Spain, Sweden, Switzerland, United Kingdom, and United States. The responsibility for this publication rests with the International Rice Research Institute. Copyright @ International Rice Research Institute 1986 All rights reserved. Except for quotations of short passages for the purpose of criticism and review, no part of this publication may be reproduced, stored in retrieval systems, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior permission of IRRI. This permission will not be unreasonably withheld for use for noncommercial purposes. IRRI does not require payment for the noncommercial use of its published works, and hopes that this copyright declaration will not diminish the bona fide use of its research findings in agricultural research and development. The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of IRRI concerning the legal status of any country, territory, city, or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries. ISBN 971-104-151-0 CONTENTS Foreword Introduction 1 Rice as a Short-day Plant 1 Growth Phases 2 Basic Vegetative Phase 4 Photoperiod-Sensitive Phase 5 Photoinductive Cycles 7 Reception of the Photoperiodic Stimulus and Translocation 9 Light Intensity and Quality 9 Interruption of the Dark Period 11 Days from Photoinductive Treatment to Flowering 12 Biochemical Changes During Photoinduction 12 Effect of Temperature on the Flowering Response to Photoperiod 13 Measurements and Methods of Testing Photoperiod Sensitivity 14 Date-of-Planting Experiments 15 Ecology and Photoperiodism 17 Terminology Used in Describing Photoperiod Sensitivity 20 Inheritance of Vegetative Growth Duration 23 Problems in the Study of the Rice Plant? fs Photoperiodism 25 Summary 26 Appendix 28 Bibliography 38 Foreword This review, first published in 1969, has been an important reference in understanding the rice plant. It has had a small but continuing demand. Many new reports on the flowering response of the rice plant have been published since the first edition. More than 100 publications were included in the third edition; this edition includes another 103 publications. For ease of reading, numbers have been used to cite the references. This review was prepared with the cooperation of the IRRI Library Staff and the technical assistance of Mr. Romeo M. Visperas, and edited by Ms. Emerita P. Cervantes. M. S. Swaminathan Director General Introduction Photoperiod influences several aspects of plant growth. Some of its effects on rices have been reviewed by Best (24), Gwinner (111), Katayama (192), Morinaga (316), Sircar (439), and Wagenaar (534). This review is primarily concerned with the effect of photoperiod on the flowering of the rice plant. It includes more than 500 papers on the photoperiodism of rice, most of which are available at the International Rice Research Institute library. Several contributions in Japanese have been translated into English and also are available at the International Rice Research Institute library. A bibliography is given at the end of this review; not all papers listed were cited in this review but were nevertheless included as future references for interested workers. Rice as a short-day plant Rice is sensitive to photoperiod . long-day treatments can prevent or considerably delay its flowering. Rice cultivars exhibit a wide range of variation in their degree of sensitivity to photoperiod (87, 254, 319, 357, 531, 563). Figure 1 shows these variations, ranging from the very sensitive to the nearly insensitive. 1. Response curves of three representative types of rice cultivars. 2 The flowering response of the rice plant to photoperiod Most of the wild species of Oryza and many of the primitive cultivated rices ( O. sativa L. ) are photoperiod sensitive and may be classified as short-day plants. Most papers agree on such a classification, and therefore in this review, rice will be considered as a short-day plant. It also will be classified into photoperiod-sensitive and photoperiod-insensitive types, the latter showing a low response or a slight delay in flowering with an increase in photoperiod. The present tendency is to select photoperiod-insensitive cultivars so that most of the cultivated rices may eventually become photoperiod-insensitive ones. These improved, early maturing cultivars may fit into the multiple cropping system characteristic of progressive agriculture. There have been reports of cultivars whose flowering is delayed by short-day treatments and hence are considered long-day plants (1, 98, 99, 239, 254, 276, 277, 279, 283, 284, 287, 291, 303, 398,443,444, 488). Heenati, for instance, is often referred to in the literature as a long-day plant (1). Short photoperiods have delayed its flowering by 10 d, but this delay is relatively short and may be the result of nonphotoperiodic factors, such as low light intensity or relatively high temperature. The delay caused by short-day treatments ranged from 7 to 12 d in the Charnock and Panbira cultivars using an 8-h photoperiod (443), about 9 d in B. 76 (303), and 13 d in T. N. 32 and T. A. 64 (287). Many of the reported long-day and intermediate cultivars were found to be short-day cultivars in subsequent testing (522). The apparent long-day reaction of Heenati resulted from using photoperiods shorter than the optimum, which delayed flowering (34). Some rices may have been classified as long-day plants because inadequate facilities were used in testing the photoperiod reaction. The range of photoperiods used has been limited, usually involving only two treatments. In some instances, the classification was based on field reaction to different planting dates (98). Short-day-treated plants were often compared with plants grown under natural day lengths (291, 303, 304). The difference and changes in temperature and the photoperiods used have made it difficult to interpret the data intelligently. As will be discussed later, many photoperiod response curves show that photoperiods longer or shorter than the optimum delay the flowering of photoperiod-sensitive cultivars (34, 513). Photoperiod response differs markedly among rices; this also explains the diversity of the results reported on the photoperiodism of the rice plant (see Appendix). However, more than 400 cultivars have been critically tested at IRRI (l59, 160, 161, 162, 163, 164, 166, 167, 168, 169, 170), and not one so far has shown a long-day response. Growth phases The growth of the rice plant can be divided into three stages: 1) the vegetative growth phase, from germination to panicle initiation; 2) the reproductive phase, from panicle initiation to flowering; and 3) the ripening phase, from flowering to full development of grain. In the tropics, the reproductive phase is about 35 d while the ripening phase ranges from 30 to 35 d. Both phases are relatively constant, although low temperatures have been known to prolong them and high The flowering response of the rice plant to photoperiod 3 temperatures to shorten them. The ripening phase may be prolonged to as much as 60 d. However, it is the vegetative growth phase whose duration generally varies greatly and which largely determines the growth duration of a cultivar, especially in the tropics. The vegetative growth phase can be further divided into the basic vegetative phase (BVP) and the photoperiod-sensitive phase (PSP). The BVP refers to the juvenile growth stage of the plant, which is not affected by photoperiod. It is only after the BVP has been completed that the plant is able to show its response to the photoperiodic stimulus for flowering . this is the PSP of the plant. Figure 2 shows the growth phases and the typical response of a photoperiodsensitive rice and a photoperiod-insensitive rice. Based on the BVP and PSP, varietal response to photoperiod can be classified into four types as shown in Figure 3 (105, 526). 2. Growth phases and typical responses of a photoperiod-sensitive rice and a photoperiod-insensitive rice. BVP = basic vegetative phase, PSP = photoperiod-sensitive phase. 3. Four types of varietal response to photoperiod. BVP = basic vegetative phase, PSP = photoperiodsensitive phase. 4 The flowering response of the rice plant to photoperiod The BVP and PSP are two separable growth phases controlled by different genes. Although some tropical cultivars may be classified as the D type having both long BVP and long PSP, most were probably eliminated during domestication since they would have had an unusually long growth period and could be planted only within a narrow range of dates. Such cultivars were found in Bangladesh and are known as Rayadas (105). The four types shown in Figure 3 were classified under one temperature condition. Norin 20 (Type A) has a short BVP. When grown in the tropics, however, it has a much shorter BVP than when grown in the temperate areas (Fig. 1). In classifying cultivars based on BVP, most of those from the low latitudes were found to have long BVP? fs (531, 532). Basic vegetative phase At the early growth stages, the rice plant is photoperiod insensitive so that the photoinductive treatments are usually started when the plants are 10-63 d old (13, 90, 142, 175, 186, 213, 230, 232, 273, 304, 316, 401, 512, 531). Because of this insensitivity to photoperiod, the early growth stage has been termed the basic vegetative phase; it is also referred to as the juvenile growth stage of the insensitive phase of the plant. Suenaga recognized the BVP as early as 1936. He measured it by taking the duration of the vegetative growth phase at optimum day length. The BVP also has been measured by subtracting 35 d from the growth duration (sowing to flowering) of plants grown at the optimum photoperiod (526). This assumes that the period from panicle initiation to flowering is about 35 d. Anema (13) modified the determination of the BVP by subtracting 35 d and the minimum number of photoinductive cycles needed for panicle initiation from the heading date. The resulting BVP values are smaller but this complex method would mean determining the minimum number of photoinductive cycles needed for each cultivar. The range of BVP reported in the literature has varied from 10 to 85 d (105, 175, 266, 273, 326, 381, 383, 401, 407, 445, 512). In an F 2 population, BVP? fs of more than 100 d were reported (249), but a BVP of this length has not been found in conventional rice cultivars. It is possible that such characters are eliminated during cultivar selection. The appendix shows the range of the BVP of the cultivars tested at IRRI. The indica cultivars generally have longer BVP (583). Other workers have reported or measured BVP in terms of leaf number (93, 215, 340, 413, 551, 575). The minimum number of leaves can be less than five. The need for determining the BVP of a rice cultivar before using it as an experimental plant material is obvious but is frequently overlooked especially in the study of the inheritance of photoperiod sensitivity. Several experiments showed that short-day treatments of seedlings accelerated heading (393, 401, 437, 438, 445) or delayed it (16, 273, 284, 287, 296, 426, 443, 447, 551). The results indicate the possible effect of photoperiod while the plant is in its early growth stage and the possible existence of a very short BVP. On the other hand, long-day treatments of seedlings have been reported to induce earliness in flowering (418, 427). These varied and conflicting results may have been caused by nonspecific factors. A good example is seedling vigor, which is The flowering response of the rice plant to photoperiod 5 known to affect the flowering date, especially in the weakly photoperiod-sensitive cultivars. The degree of sensitivity of rice plants has been reported to increase with age (142, 190, 195, 202, 205, 347, 512). The increase in leaf area accompanying advancement in age does not explain this increase in sensitivity (413). An increase in sensitivity with age up to 28 d and then a decrease in sensitivity with older plants (35- to 42-d-old plants) has been reported (296). The delay probably resulted from the setback from delayed transplanting and not from plant age because the plants were already 63 d old when transplanted, with some already flowering. The optimum age of responsiveness is probably the result of growthlimiting factors, such as space and nutrients and delayed transplanting. Katayama (202) indicated that the BVP, or aging effect, probably resulted from small leaf area and (or) low metabolic activity and (or) lack of a specific metabolic pattern in young plants. The substance causing response to short-day conditions is produced in too small a quantity to affect morphogenesis at the growing point, but increases gradually with increasing age. Studying this aspect, Suge (460) found that the growth inhibitors in the plant were greatly reduced as the plant grew. However, it is not known whether these inhibitory substances are essentially involved in the sensitivity of the plant to photoperiod. In some instances, the apparent low sensitivity of the younger plants may be a matter of completing the BVP. If the photoinductive cycles were given before the BVP of the plants had been completed, the effective photoinductive cycles would be less and the resulting response of the plants would be smaller. The transition from the BVP to the PSP is not well known; it could be abrupt or it could involve a gradual buildup. Using several cultivars, Best (26) found that the insensitive phase (BVP) changed to the fully sensitive phase (PSP) within a week. The following are possible explanations for the existence of the BVP (26): 1) The first leaves formed are completely insensitive to photoperiod. 2) The first leaves formed have very low sensitivity that they do not reach an adequate level of induction to evoke floral initiation before the more sensitive leaves formed at higher nodes have reached this stage. ) The first leaves formed do not attain the induced stage before the (early) senescence of these leaves. 4) The total leaf area required before the plant can react by floral initiation to the inductive photoperiod is so large that it is reached only at a relatively late stage of plant development. 5) The growing point of the young plant is unable to react to the floral stimulus or the st imulus cannot reach the growing point. Photoperiod-sensitive phase The PSP or the eliminable phase (186) is the growth stage indicative of the rice plant's sensitivity to photoperiod. In photoperiod-sensitive cultivars, the PSP determines the rice plant? fs sensitivity. The PSP of photoperiod-insensitive cultivars ranges from 0 to 30 d while that of sensitive cultivars lasts from 31 d or longer. Under continually long photoperiods, 6 The flowering response of the rice plant to photoperiod some cultivars have been reported to remain vegetative even after 12 yr of growth (234). The PSP is usually determined by subtracting the minimum growth duration from the maximum growth duration of a cultivar (526). Because many cultivars remain vegetative for a long period if grown under long-day conditions, experiments are usually terminated after 200 d and the PSP of the cultivar is given the value of 200+. Besides measuring the PSP, there are many other ways . to be discussed later . of determining a cultivar? fs sensitivity to photoperiod. A rice cultivar? fs response to photoperiod may be measured by the length of the PSP, which in turn is determined by both the critical and optimum photoperiods of the cultivar. Because these two terms have been used interchangeably and in many ways, the following definitions will be adopted herein. Optimum photoperiod is the day length at which the duration from sowing to flowering is at a minimum (34). Critical photoperiod is the longest photoperiod at which the plant will flower or the photoperiod beyond which it cannot flower. Figure 1 shows that BPI-76 has an optimum photoperiod of 10 h and a critical photoperiod of 13 h. Tainan 3 has an optimum photoperiod of 12 h but no critical photoperiod because it flowered under all photoperiods. The critical photoperiod determines whether a cultivar will flower when planted at the usual time at a certain latitude, while the optimum photoperiod determines whether it will flower within a reasonable time if planted during a period with longer days than would normally occur during the growing season. With BPI-76, if the optimum photoperiod is 10 h and the delay under photoperiods longer than 10 h is great, one would expect the flowering of this cultivar to be greatly delayed when planted in the northern latitudes where the photoperiod during the growing season is about 14 h. If the critical photoperiod is 12 h, flowering will occur very late at high latitudes, and if flowering does occur, the crop will not mature in time because frost will kill it. A cultivar with a long optimum photoperiod or no critical photoperiod would have wider adaptability . it could be planted at any latitude and in any season, provided it is not too sensitive to temperature. Optimum photoperiod The optimum photoperiod differs with cultivars although many workers have observed it to be 8-10 h (39, 116, 135, 142, 311, 362, 371, 393, 512). Using intermediate photoperiods of less than and more than 10 h may reveal more important information. But this will require facilities in which a maximum of 15-min difference in photoperiods can be accurately obtained. There are also indications that the optimum photoperiod increases with increase in temperature Njoku (335) did not find any optimum photoperiod in the varieties he studied. The photoperiod he used was as short as 9 h, well below the range of natural day lengths. Cultivars with optimum photoperiods longer than 10 h have also been reported (26, 90, 320, 322, 362, 568). The less sensitivity to photoperiod, the longer is the (394). The flowering response of the rice plant to photoperiod 7 ptimum photoperiod (116, 311). However, others found no correlation between the optimum photoperiod and the photoperiod sensitivity of the many cultivars they tested (572). A photoperiod longer or shorter than the optimum has been shown to delay flowering, the delay depending upon the cultivar? fs sensitivity (311, 316, 319, 371, 393, 459, 5 13, 568). The term supraoptimum photoperiod has been used when the photoperiod is shorter than the optimum. Panicle initiation in plants receiving a photoperiod as low as 4 h has been reported (140). No flowering has resulted under a 2-h light period (140). Plants receiving 8-h light and varying dark periods from 16 to 64 h showed inhibited shoot apex conversion (219). This was ascribed to inadequacy of carbon compounds for synthesis of requisite quantity of flowering hormone. The turning point mentioned by Yu and Yao (568) is similar to the optimum photoperiod, but the photoperiod values they reported were larger because these were not the photoperiods at which growth is shortest but the photoperiods at which the first long-day effect is manifested. Critical photoperiod Scripchinsky (417), reviewing the literature on rice, indicated that the rice plants have a ? critical length of day for flowering.? h Later studies showed the presence of a critical photoperiod ranging from 12 to 14 h (175, 209, 244, 354, 478, 490, 500, 553). The critical photoperiods determined under controlled photoperiod rooms were almost the same as the day length from sunrise to sunset at 30 d before flowering under natural conditions (499). The lower the latitude of origin of a cultivar or strain, the shorter is its critical photoperiod (196, 356). The critical period is influenced by temperature (566) and lengthens as the plant becomes older (2 12). The PSP of a cultivar is probably a measure of the combined effect of photoperiod on its optimum photoperiod and critical photoperiod. The shorter the critical photoperiod, the longer is the PSP. Short optimum photoperiod is also associated with long PSP. Photoinductive cycles A photoperiodic cycle that induces the initiation of flowers on plants is called a photoinductive cycle. A 10-h photoperiod alternating with a 14-h dark period is one possible photoinductive cycle of a short-day rice cultivar. The minimum number of photoinductive cycles necessary to initiate the panicle primordium of a rice plant varies from 4 to 24. This required minimum number varies not only with cultivar, but also with the photoperiod being used (13, 21, 26, 142, 195, 292, 338, 344, 408, 449, 500, 527, 529). The number of photoinductive cycles necessary increases with photoperiod length (190, 195, 203, 204, 527). According to Katayama (190), the minimum number increases proportionally with the photoperiod used, although others (527) failed to obtain a proportional increase using a different cultivar. Katayama (190) found that the minimum number was lower in cultivars from higher latitudes than in those from lower latitudes. The flowering response of the rice plant to photoperiod Suge (463) showed that different numbers of photoinductive cycles produced different amounts of floral stimulus. He also found that Gibberellin A3 reduced the minimum number of photoinductive cycles necessary to induce flowering. However, gibberellin alone did not induce flowering under noninductive photoperiods. That a certain number of photoinductiv e cycles is required to induce flowering suggests that the stimulus produced by the treatment is cumulative and that flower induction occurs when the stimulus has reached a certain threshold level (205, 206, 208). Photoinductive cycles interrupted by noninductive cycles can negate to different degrees the effect of the photoinductive cycles (200, 206, 345). There are also indications that emergence of the panicle from the flag leaf sheath is a process separate from panicle initiation. For example, internode elongation, after the panicle has been initiated, proceeds more rapidly at shorter than at longer photoperiods (26, 37, 67, 135, 425, 451, 512, 529), and earliness is further induced if the treatment is prolonged until flowering (33, 438, 498). It is possible, however, that panicle initiation and exsertion are separate processes, but certainly the latter proceeds only after the panicle has been formed. The effect of photoperiod on exsertion may be on fuller development of the panicle, hence indirectly affecting elongation of the first internode or exsertion of the panicle. Plants subjected to insufficient photoinductive cycles sometimes form panicles but no emergence occurs (see Table 1) (92, 122, 344, 512, 526). A difference of two photoinductive cycles could make the difference between exsertion or nonexsertion of the panicle. Several workers, however, have reported that photoperiod has only a slight effect on culm elongation and panicle emergence (85, 116, 338, 473); but the cultivars used (85, 338, 473) were generally weakly photoperiodic because the differences between the control and the treated plants were relatively small (16 d at most). In another instance, the treatment was started at a later stage . 20 d before the standard heading time . at which time the plants had received sufficient photoperiodic stimulus for panicle initiation and emergence (1 16). In another experiment, long photoperiods had no effect on the terminal bud that had reached the stage of differentiation of secondary branch primordia (345). Reversals from a reproductive to a vegetative phase have been reported (54, 342). In some instances, however, the panicle is initiated and differentiated but Table 1. Response of 30-d-old BPI-76 seedlings given different numbers of 10-h photoinductive cycles. Days from sowing Days from sowing Cycles (no. ) to panicle to panicle initiation emergence 8 ** 10 47 ** 12 47 88 Continuous 46 66 *No panicle initiation 200 d after treament. **No panicle meregence 200 d after treament * The flowering response of the rice plant to photoperiod 9 does not emerge (526). The unexserted panicle ceases to grow, and instead the terminal growth is dominated by a shoot from a node below the panicle. Such a situation is not a true reversal of the growing point. In more recent histological studies, incomplete short-day treatment changed the bract pri mordium into a leaf primordium, a true reversal of some parts of the growing point (346). Reception of the photoperiodic stimulus and translocation The photoperiodic stimulus may be received by the leaves of the rice plant (24). The leaf sheaths can receive the stimulus as shown by removing the leaf blades and subjecting the plant to photoinductive treatments (26, 142, 481). More photoinductive cycles were needed to induce flowering when the leaf blades were removed (142). Defoliated plants responded to light interruption given during dark periods as well as the intact plants (142). In one cultivar, the culm received the photoperiodid stimulus (26). Evidently, the leaf most receptive to the stimulus is the youngest fully formed leaf (263). The first leaves, up to the sixth leaf, are either insensitive or have low sensitivity to photoperiod (26). It is difficult to study this aspect of leaf sensitivity because grafting experiments with the rice plant are difficult. Removing the leaves at regular intervals after the end of the photoinductive cycles showed that the floral stimulus moves gradually from the leaves to the terminal bud (142, 464). The translocation of the stimulus depends on temperature. It was also reported that the rate of translocation of the stimulus is the same regardless of the number of photoinductive cycles received by the plant (463). The question of stimulus movement from one tiller to another has also attracted the attention of several workers. When a plant was divided and half was kept under a 24-h photoperiod and the other half under an 8-h photoperiod, the half subjected to the short-day treatment flowered while that under long-day treatment remained vegetative (230, 232). The results indicate that the stimulus is not transmitted from one tiller to another. This finding has been substantiated by other workers using different cultivars and methods (263, 408, 521). Manuel and Velasco (263) concluded that the stimulus that induces flowering can be conserved in the stubble and later transferred to the ratoon but not to a neighboring tiller of the same age as the donor. Sasamura (413), however, reported that the floral stimulus goes from the main culm to its tillers. The irregularities observed in photoperiod-sensitive cultivars when planted during the off-season, for example, the high number of nonflowering tillers, have been attributed to the effect of the photoinductive cycles received by the plant and their nontranslocation to the succeeding tillers formed (521). Light intensity and quality The light intensities used to prevent or delay flowering varied from 1 to more than 200 lx. Incandescent, tungsten, as well as fluorescent bulbs have been used (69, 143, 310, 396, 484, 489, 503, 538, 565, 570, 577). The brighter the illumination, the stronger the retarding effect. 10 The flowering response of the rice plant to photoperiod Delay in flowering with light intensities varying from 10 to 100 lx and even at 1 lx (310, 484) has been reported (538, 565, 589). Extending the day length using light intensities of less than 200 lx during the first or last 3 h of the 12-h dark period did not prevent flowering (478). In another experiment, 2-h illumination at 15 lx before a 9-h dark period showed some inhibiting effect and 1-h illumination at 500 lx incandescent light before a 9-h dark period inhibited flowering (143). In correlating laboratory studies with field studies, the natural photoperiod used is usually based on the sunrise-to-sunset duration. Such measurements are unsatisfactory in assessing periods of effective light because very low light intensities have been known to effect photoperiod responses in some experiments. Civil twilight in the morning can generally delay flowering but civil twilight in the evening may or may not delay flowering (143, 196, 205, 502). Civil twilight ends when the light intensity is about 4 lx. Twilight, of course, varies with localities and within the year. The critical light that results in delayed flowering is around 5 lx and sometimes 10 lx, depending on variety and other factors (174). Twilight intensity also varies and may be higher in the morning than in the afternoon (Fig. 4). Katayama (196) attributes the greater effectiveness of the morning twilight to higher intensity. Cloudy weather affects twilight duration. Takimoto and Ikeda (478), however, concluded that the photoperiodically effective day length is equal to the astronomical day length (sunrise to sunset) because twilight (less than 200 lx) had little effect on photoperiodic induction in their experiment. Wormer (538) showed that low light intensities for 6 h (10-100 lx) given after a 12-h daylight can delay flowering. Farmers have complained that their rice plants did not flower regularly because of the electric lights installed along their fields (552). One incident has been reported in which the light from a flame of waste natural gas prevented normal 4. Change of light intensity during civil twilight (after Katayama [196]). The flowering response of the rice plant to photoperiod 11 flowering in rice. The effect of light was noticeable up to about 270 m from the flare (22). Although light from incandescent bulbs is generally used for photoperiod studies, other colors have been tried in rice. The blue-violet part of the spectrum has been shown to retard flowering (260) as has infrared light (323). The delay in flowering caused by green light is very slight, only 4-5 d later than natural day length (234). Green has, therefore, been used in light traps for the moth. Red light is the most effective in delaying flowering, while blue showed some effect only at high intensities and in the most photoperiod-sensitive cultivars (26, 146, 153, 503). The phytochrome pigment is generally regarded as the system that interacts with photoperiod or with different light qualities, such as red, far-red, and blue. Such pigment has been studied in rice coleoptile by Pjon and Furuya (378, 379). For panicle initiation, rice needs a high light intensity during the light period. The inhibition caused by low-intensity light during the light period can be overcome effectively by exposing the plant to high-intensity light immediately before or after the inductive dark period (140, 145). This phenomenon is similar to that reported in other short-day plants and is evidently a carbohydrate requirement. This requirement would explain why a 2-h light period followed by 22-h dark period did not induce flowering (140). Ikeda (145) reported, however, that plants growing in low-intensity light during the photoinductive period but briefly exposed to high-intensity light before the inductive dark period had floral induction, suggesting that light requirement for floral induction of rice is not entirely concerned with photosynthesis. In the flowering response of the rice cultivars to photoperiod, red light given during the dark period inhibited flowering (136, 146, 148, 411, 442). The effect of red light increased with intensity. Red light, as low as 10 ? EW/cm 2 given for 3 h or 290 ? EWc/cm 2 for 15 min in the middle of the dark period, inhibited flowering (146, 148, 149). Red light was most effective in inhibiting panicle initiation when given in the middle of the dark period (150). With red light, the period of exposure needed to inhibit floral development was shorter than with white light (146). The inhibiting effect of red light has also been shown in experiments involving red and far-red lights. Far-red after red nullifies the delaying effect of red light and promotes flowering (411). Far-red before a 9- or 10-h dark period promotes flowering and this effect can be reversed by red light (146, 149, 152). Far-red enhances flowering whereas blue retards flowering (185). Far-red after the critical dark period can shorten the critical dark period as well as reduce the minimum number of inductive cycles required (145). Interruption of the dark period Sensitive strains of rice respond to light interruption (26, 69, 218, 232, 260, 323, 449, 570, 577). Light given in the middle of the dark period delayed the flowering of the sensitive cultivar Shuan-chiang (570). The light intensity used was 1001x and the duration varied from a flash to as long as 15 min. The degree of delay was greater in the light interruption of a 12-h dark period (12 light and 12 dark) than of a 16-h dark period (8 light and 16 dark) (577). Interrupting the light period with darkness did not accelerate flowering. 12 The flowering response of the rice plant to photoperiod The earlier the interposition of the light during the dark period, the greater was the delay (449). The findings show that the flowering response of the plant is determined by the longest dark period. Days from photoinductive treatment to flowering The literature indicates that the number of days from panicle initiation to flowering is about 35. Many workers have reported that the difference among cultivars is small (7, 407, 511, 551). Others found that the number of days from panicle initiation to flowering ranges from 10 to 241 d (425). It seems obvious, however, that 10 d is too short for the full development of a panicle. Flowering may be delayed by long photoperiods after panicle initiation (176, 524). But if the plants are given photoinductive cycles beyond the minimum requirement, the subsequent photoperiods have very little effect on flowering and elongation (501, 524). Auxin application can nullify the delaying effect of long photoperiods (176). Under natural day length, the number of days from the first-bract differentiation stage to flowering varied from 27 to 46 d, depending upon the cultivar and time of sowing (14, 270). Reports vary on the number of days from the start of the photoinductive treatment to flowering. Misra (285) reported 37 d in 30-, 40-, 50-, 60-, and 70-d-old plants of the cultivar T. 36 using a 10-h photoperiod. Fuke (93) noted that the plants flowered about 28 d after treatment. The number of days from photoinductive treatment to flowering depends upon the photoperiod being used. Panicle initiation and flowering were earlier under the 10-h than under the 11- and 12-h photoperiods (527). Using 168 F 2 plants, those treated under the 10-h photoperiod took 30-47 d to flower, or a mean of 35. d (Li, unpublished data. For practical purposes, an estimate of 35 d should be workable. Thus, to obtain the BVP or the time of panicle initiation, 35 d can be subtracted from the minimum growth duration of the cultivar. In studying the effect of photoperiod on the flowering of the rice plant, the most fundamental consideration is panicle initiation because it marks the actual change from the vege tative to the reproductive phase. Instead of using this as a basis, however, most studies use the flowering date, which is only a projection of the variations of the date of panicle initiation. To a certain extent, several factors can affect the stage from panicle initiation to emergence. In some instances, panicle initiation can occur without the subsequent emergence. The panicle primordium is aborted and a vegetative shoot may dominate the growing tip (527). A methodological question might therefore arise regarding accuracy of the experiments based on flowering date. The practicality of the method, however, far outweighs the need for extreme accuracy. Biochemical changes during photoinduction Very little work has been done on the chemical changes occurring during photoinduction and panicle development in rice. An increase in the rate of respiration of rice shoot apices with each photoinductive cycle given to the eighth The flowering response of the rice plant to photoperiod 13 day, followed by a gradual decline in rate, has been reported (293). The peak of the respiration rate almost coincides with the minimum photoinductive cycles needed by the rice plant at 8 h of photoperiod. The results suggest that the photoperiodic mechanism in the flowering of rice involves a respiratory shift. This corroborates the findings of Elliot and Leopold (86) who used other plant species. The changes in carbohydrate and nitrogen content of rice plants subjected to short days were also studied by Misra and Mishra (299). Unfortunately, the difference in heading between treated and control plants was only 4 d. Khan and Misra (222) reported an increase in sugar and nitrogen content of the leaves when subjected to photoinductive cycles. Photoinduction increases the gibberellic acid activity, although the value is low (461). This immediate rice, visible after three photoinductive cycles, returns to a level lower than that of the original. The rice plant is difficult to use for studies on biochemical changes during reproduction. Perhaps it is best to leave this type of study to other short-day plants. Effect of temperature on the flowering response to photoperiod The flowering of the rice plant is mainly controlled by two ecological factors . day length and temperature . which are often interrelated. The plant may respond to temperature and photoperiod simultaneously, but the degree would vary according to the cultivar. Cultivars have been classified based on these two factors (248, 356, 530). Temperature affects both the photoperiod-sensitive and photoperiodinsensitive cultivars. Generally, high temperature accelerates and low temperature delays heading (5, 6, 90, 126, 186, 307, 339, 340, 370, 376, 409, 410, 439, 456, 531). Some reports, however, have shown that high temperature delays flowering (15, 18, 394). The acceleration of the photoperiod response by high temperature is an overall effect, but it does not indicate the specific effects on the different stages leading to flowering. The effect of temperature on the BVP, photoinductive period, panicle differentiation and development, and critical photoperiod has not been fully studied. Uekuri (506, 507) studied the effect of low temperature during the BVP and found a definite delay in attaining the PSP. The degree of extension of the BVP by low temperature varied with the cultivars used. The growing point of the shoot is the receptive organ for the low-temperature effect, not the leaf blades (506). Ahn (5) reported that high temperature reduced the BVP but had very little effect on the PSP. As early as 1931, Fuke had considered the effect of temperature during the photoinductive period. He used snow to lower the darkroom temperature, but the 5-10? †¹C decrease had little effect on heading. Temperatures above 20? †¹C to 29? †¹C accelerate panicle initiation (24, 341). Vergara and Lilis (524) showed that the vegetative primordium was converted to reproductive primordium at the same time or at the same morphological stage regardless of temperature (21-32? †¹C). 14 The flowering response of the rice plant to photoperiod Haniu et a1 (1 15) found similar results. These results contradict those reported by Noguchi and Kamata (341) and Best (24). Temperatures below 15? †¹C inhibited initiation and bud development (156). Floral induction, however, is possible at 15? †¹C (341) but not at 12 or 40oC (115). Because many test plants died in the growing process, 15? †¹ C is assumed to be near the lowest limit for rice growth (341). The optimum temperature reported for photoinduction is 30o C (1 15). The question still remains as to whether a critical temperature for photoinduction exists. The optimum temperature for photoinduction may vary depending upon the photoperiod being used. The optimum temperature tended to be higher under a longer photoperiod and vice versa (24, 364). Putting it another way, at a certain temperature each cultivar has its own optimum day length under which it flowers at the earliest date (459, 572). Detailed microscopic studies of the development of the panicle primordium have shown that high temperature accelerates panicle development (260). The critical temperature for young panicle differentiation has been reported to be 18oC (555). Best (24) has also shown that panicle development, especially in its later stages, is accelerated at high temperatures (35-37oC). On the other hand, low temperature markedly retards panicle primordium development, and, below 25oC, the panicle may not emerge completely from the flag leaf sheath (24). A night temperature of 24. 4oC was found more favorable than 29 and 35? C in accelerating the flowering of the Elon-elon cultivar (263). High night temperature accelerates flowering (220). This was attributed to increased production of florigen during the dark period. This may not be the case and dissecting plants after photoinductive treatments may reveal if it was an acceleration in panicle development and exsertion rather than in panicle initiation. Others have found that the acceleration in flowering with high temperature is the result of acceleration in panicle exsertion, which, in turn, is the result of shorter leafing interval (524). Obviously, caution should be taken in determining the time of panicle initiation by observing the heading date because the exact date of panicle initiation cannot be determined by this method. Measurements and methods of testing photoperiod sensitivity Most studies on the photoperiodism of the rice plant have been considered from two standpoints, namely, classification of the cultivar into photoperiod-sensitive and photoperiod-insensitive types and measurement of the degree of sensitivity. The classification may be relatively easy, but the measurement is rather complex (195). As a result, several methods of measuring photoperiod sensitivity have been developed. Studies on the measurement of photoperiod sensitivity are usually based on the reduction in the number of days as a result of short-day treatment (1 16, 195, 205, 327, 329, 357, 553, 574). Other methods were more specific; they measured the optimum photoperiod (40), critical photoperiod (351), or the gradient of the response curve (34, 192, 247) as the basis of sensitivity. Hara (116) was the first to measure photoperiod sensitivity using the formula: X The flowering response of the rice plant to photoperiod 15 = T . Y/Y X 100, where Y is the number of days required to head under standard conditions and T is the number of days required under an 8-h photoperiod. Several similar formulas have been used by other workers. The percentage or index obtained from such formulas, however, does not clearly define photoperiod sensitivity. The results usually apply only to the area where the rice was tested since the natural day length is usually used as the control. Chandraratna (37, 40) used second-degree polynomials to compute the minimum heading duration and optimum photoperiod; this method involved using at least three photoperiods. He showed that cultivars differ in both characters. Oka (352) and Katayama (192, 201) measured the critical photoperiod and the degree of sensitivity of several cultivars using different methods and formulas and came up with their preferred method of measurement. Both workers used the natural day length as a basis for computation and assumed that flowering occurs 30 d after photoinduction. Best (25) and Li (249), using a method similar to Chandraratna's (34, 37, 40), measured sensitivity based on response curves obtained by plotting the time from sowing to floral initiation on the ordinate and the photoperiod used on the abscissa. The method, however, requires a wide range of photoperiods. Li (249) also studied photoperiod sensitivity in terms of the BVP and the PSP. The BVP was obtained in plants grown under 10 h of light, and the PSP (which is a measure of sensitivity) by subtracting the growth duration under the 10-h photoperiod from that under the 16-h photoperiod. The PSP values obtained show the possible maximum range in growth duration as a result of extending the photoperiod. The photoperiodic characteristics of a rice plant have been described by Stewart (458) who used a different criterion based on 1) basic vegetative period in terms of degree-days (based on temperature accumulation), 2) photoinduction period in degree-days or degree-minutes (using accumulated night length), and 3) panicle development period in degree-days (based on temperature accumulation). Tests under field conditions were analyzed by this method and predictions were made on the response of the cultivar sown in different months. In Japan, the flowering response is evaluated using the floral stages (135, 463). The Japanese workers have used the scale of 0-7, based mainly on the length of the developing panicle. This destructive measurement is more accurate than the usual days from sowing to flowering or treatment to flowering. The choice of the most appropriate method of testing and describing the response to photoperiod depends upon the purpose of the experiment and the available facilities. From the physiological standpoint, however, controlled photoperiod and temperature are desired because of their advantages over natural photoperiods and temperatures. Date-of-planting experiments Day length changes rhythmically within a year and varies depending upon the latitude. The amount of change in day length during the rice cropping season differs from one latitude to another (Fig. 5). Even in locations at the same latitude the day length during the cropping season may differ because the planting dates 16 The flowering response of the rice plant to photoperiod 5. Day length changes during the cropping season at various locations in Asia. may differ greatly depending mostly on the rainfall pattern at each location. At northern latitudes (Sapporo, 43? †¹ N, and Konosu, 36? †¹ N) day ength increases and then decreases during the cropping season (Fig. 5). At lower latitudes (Taipei, 25? †¹N, and Los Banos, 14? †¹N) day length decreases during the main growing season. Near the equator (Bukit Merah, 5? †¹N) there is little change. These differences in day length during the growing season may account for the wide range of photoperiod response of rice cultivars. A rice cultivar that must have less than 12 h o daylight to flower will obviously flower too late at the northern latitudes because frost will set in before harvest. In the northern hemisphere, the longest days are in June and the shortest are in December. Taking these into account, the photoperiod response of the rice cultivars can be tested to a limited extent by planting the cultivars at a certain location at different dates. Maximum differences in growth duration can be obtained in the May and November plantings if temperatures are not too low for growth. If a rice? fs growth duration changes more than 30 d, agronomists usually consider it photoperiod sensitive or a seasonal cultivar. As Best (24) has pointed out, this criterion is not specific enough for research on photoperiodism, and caution should be taken in evaluating the data obtained. These phenological data, however, are important to breeders in selecting ecotypes. This method of testing sensitivity to photoperiod has been followed in Australia (245), Brazil (l03, 579), China (44, 356, 582), India (98, 99, 101, 214, 220, 295, 298, 423), Indonesia (467), Japan (533, 548), Korea (247, 466), Malaysia (74, 77, 244), Philippines (91, 512), Russia (452), Senegal (66), Sierra Leone (68, 536), Sri Lanka (112, 259, 402), Thailand (381), Trinidad (325), and United States of America (177, 180). The flowering response of the rice plant to photoperiod 17 These experiments strongly confirm the existence of wide cultivar differences in the effect of planting date on flowering date. Many of the results obtained from this type of testing, however, are not applicable to identical cultivars grown at different latitudes. A cultivar can be insensitive to day length in Malaysia but sensitive in Taiwan. Results of field tests at a certain latitude are, therefore, not always applicable at another latitude. Some published papers on the use of this testing method failed to mention latitude or the place where the tests were conducted. Under natural conditions very small differences in day length can affect the rice plant. In Malacca (Malaysia), the difference between the maximum and the minimum day lengths is only 14 min and yet the cultivar Siam 29 takes 329 d to flower when planted in January and only 161 d when planted in September (76). Another instance showing the sensitivity of the rice plant to small differences in day length was reported in a date-of-planting experiment in Malaysia (244). There was a difference of as much as 156 d in the growth duration of photoperiodsensitive cultivars when planted in the same month but in different years (Table 2). This presumably resulted from differences in weather during the critical periods. Cloudy weather early or late in the day shortens the twilight hour, thus shortening the day length. Toriyama et al (490) tested rice cultivars involving not only monthly planting but also sowing at different latitudes (Sri Lanka, Taiwan, and Japan). This gives a better idea of the photoperiodic response of the cultivars but involves much work and cooperation. Ecology and photoperiodism Rice can be grown over a wide range of environmental conditions, from the equator to about 53? N latitude, leading to the differentiation and establishment of various ecotypes and forms. The great diversity in photoperiod sensitivity from one latitude to another or within a latitude probably indicates that the rice cultivars predominantly cultivated in each area are those that have been selected on the basis of local adaptability (that is, adaptability to the temperature of the rice-growing season, day length, and duratio n of the growing season) to assure the full development of the plant and the best possible balance between vegetative and reproductive growth (423, 530, 532, 584, 585). Table 2. Growth duration (days from sowing to flowering) of photo. period-sensitive cultivars when planted in January 1962 and 1963 at several localities in Malaysia (244). Cultivar Locality Jan 1962 Jan 1963 Difference Engkatek Telok Chengai 136 292 156 Kota Bahru 146 243 97 Kuala Lumpur 134 97 37 Subang Bukit Merah 270 224 46 lntan 117 Kuala Lumpur 171 138 33 Kota Bahru 276 176 100 18 The flowering response of the rice plant to photoperiod A major problem in studying the ecology of the rice plant, especially in reference to photoperiodism, is that cultivars in farmers' fields keep changing. For example, Hara reported in 1930 that Japanese cultivars were more sensitive than the cultivars from mainland China and Taiwan. He concluded that the lower the latitude of the region of the native habitat, the less sensitive were the cultivars there. Wada (531), using 134 cultivars, showed contrasting results . the cultivars from the northern region of Japan had lower photoperiod sensitivity than those from the southern region. Recent papers, however, generally agree that among the photoperiod-sensitive cultivars, the lower the latitude ofdistribution, the higher the sensitivity (351, 352, 356, 531, 583). The cultivars in the tropics or lower latitudes are usually late maturing (long growth duration). Many studies show that the late cultivars are more sensitive to photoperiod than the early ones (116, 248, 357, 511, 563, 583). In the tropics, where rice can be grown any time of the year provided there is sufficient water, photoperiod sensitivity presents certain problems. During the off-season, when the day length during the early growth stage is increasing, the sensitive cultivars are uneconomical to use because they take a very long time to produce any grain. For wider adaptability, cultivars should have low photoperiod sensitivity (53, 70) and thus have little differences in growth duration when planted at different times of the year or at varying latitudes. Insensitive cultivars have been successfully grown at different latitudes where rice is used as a crop (45, 351, 352, 511, 532, 568. This indicates that it should not 6. Growth duration of IR8 planted in June or July at 12 sites in Asia. La Trinidad and Kanke are high-altitude areas (52). The flowering response of the rice plant to photoperiod 19 e difficult to introduce new photoperiod-insensitive cultivars to different ricegrowing areas or to culture them year-round in the tropics. The plant breeders, as the varieties coming out indicate, are developing more photoperiod-insensitive cultivars. Extensive testing in various rice-growing areas of the world has established the wide adaptability of photoperiod-insensitive cultivars. In general, the longer the BVP the less variation ingro wth duration and the stronger the PSP the greater the variation in growth duration (581). The wide adaptability and the stable growth duration of IR8, a photoperiod-insensitive cultivar, are indicated by the data furnished by cooperators in various parts of the world. IR8? fs growth duration varied within a range of 20 d at latitudes from 11o to 27oN except at high altitudes where low temperatures prevailed during part of the growing season (Fig. 6). A more illuminating example of the effect of temperature comes from monthly planting at Los Banos, Philippines, and at Joydebpur, Bangladesh (Fig. 7). A comparison between the monthly mean temperatures and mean photoperiods shows that the more variable heading pattern at Joydebpur is more closely associated with temperature rather than with the prevailing photoperiod. The effect of low temperature on the improved tropical cultivars becomes more obvious in photoperiod-insensitive cultivars. 7. Mean monthly temperatures and day length in relation to the growth duration of IR8 at Los Banos, Philippines, and Joydebpur, Bangladesh (52) 20 The flowering response of the rice plant to photoperiod Sensitivity to photoperiod of rice cultivars in the deep water areas is an important characteristic for survival (104, 520). The floating rice cultivars are highly photoperiod sensitive. They are planted early in the season when the soil can still be worked and without danger of submerging the young seedlings. Flowering occurs when the floodwater peaks or starts receding. If the cultivar flowers when the floodwater is still rising, it would mean the complete loss of the crop if the panicles are submerged. Elongation ability ceases after panicle emergence. Harvesting is usually done when the floodwaters have receded. The maturity of floating rice cultivars coincides with the receding of the annual floodwaters which may be 150-270 d after sowing. Such a long growth duration requires a photoperiod-sensitive cultivar. So far, there is no known tropical cultivar that has a long growth duration and is not sensitive to photoperiod. Photoperiod sensitivity may work as a safety mechanism when precise planting dates are not followed and environmental conditions such as water level cannot be effectively controlled. If the date of sowing or transplanting is delayed because of insufficient rainfall, a photoperiod-sensitive cultivar may still mature at its usual time (352, 382). Plants are not seriously damaged if left in the seedbed for prolonged periods because the growth duration of the main crop is sufficiently long for the plants to adjust. Thus, land preparation and transplanting can be staggered (382). Maturation of the crop at the same time. as with photoperiod-sensitive cultivars planted at different dates, may reduce rat and insect damage in any one field. Also, harvesting and drying are simplified. If the soil is not sufficiently fertile, a photoperiod-sensitive cultivar will continue its compelled vegetative growth until the short days come. This would give the plant enough time to reach a reasonable plant weight and accumulate enough carbohydrates before flowering (528). Thus, a photoperiod-sensitive cultivar generally may be more resistant to unfavorable conditions. Long-growthduration cultivars (essentially photoperiod sensitive) are least affected by strong soil reduction (549). Most upland rice cultivars have short growth duration and are photoperiodinsensitive (11, 12). However, in areas where the rainfall pattern is bimodal, as in northern Thailand, the cultivars are of medium growth duration and are photoperiod-sensitive . possibly another indication of the greater specific adaptability of long-growth-duration cultivars to adverse conditions. The sensitivity to photoperiod of wild species has also been studied in relation to their ecological distribution. Most of the wild rice materials tested were sensitive (191, 201, 205, 209, 353). They suggested that this sensitivity favors the wild rice plants and is perhaps essential to their survival. Terminology used in describing photoperiod ensitivity There is confusion in the terms used to describe the response of the rice plant to day length (515). Often, the terms used for growth duration are also used for response to photoperiod (see Table 3). As early as 1912, Kikkawa pointed out that The flowering response of the rice plant to photoperiod 21 Table 3. Some terms used in describing the growth duratio n and day length response of rice cultivars. Terms References Response to day lengths: date fixed vs period fixed season fixed vs period fixed season bound vs period bound timely fixed vs periodically fixed short-day plant vs long-day plant ensitive vs indifferent sensitive vs insensitive sensitive vs less sensitive short-day plant vs indifferent plant strongly photoperiodic vs weakly photoperiodic sensitive vs photosensitive vs photononsensitive day length sensitive vs day photoperiodic photoperiodic insensitive length nonsensitive early, medium, and late long-aged vs short-aged early flowering vs late flowering late maturing vs early maturing Season of planting: aman vs non-aman yala vs maha winter vs summer main-season vs off-season first crop vs second crop wet vs dry season aus, aman, boro, rabi, kharif Growth duration: 33 7 214, 511 308 1, 99, 336 3 68, 352, 353 21, 98, 449, 538 563 51 1 195, 352 339 574 91, 276, 277, 281 259 158 3, 230, 374 427 112 444 Malaysia, Indonesia, an d Thailand China Philippines Bangladesh, India it is meaningless to classify the rice cultivars of the world into such groups as early, medium, late, aus, or aman. He said, however, that this classification is useful in districts where the climates are similar. The use of the terms photoperiod-sensitive and photoperiod-nonsensitive in reporting the flowering response of a rice cultivar to changes in day length has been suggested (515). Weakly photoperiod-sensitive is sometimes used in place of photoperiod-nonsensitive because the existence of a completely photoperiod-nonsensitive cultivar is difficult to prove. Weakly photoperiod-sensitive is also used to describe cultivars whose flowering is delayed by as many as 70 d by long photoperiods. However, those types can be planted any month of the year in the tropics and can be expected to flower within the crop season. The terms short-day plant and long-day plant are not satisfactory because most rice cultivars today are short-day plants. Sensitive and insensitive, sensitive and indifferent, and sensitive and less sensitive are ambiguous terms. Because the response being described is a response to light period and not only to light, the terms photosensitive and photononsensitive are inappropriate. 22 The flowering response of the rice plant to photoperiod 8. Effect of four photoperiod treatments on the seeding-to-heading period of seven rice cultivars. Chang and Vergara (51, 52, 53) classified rice cultivars into four types using the length of the BVP and PSP as criteria (Fig. 8). Their classification was based on duration of plants grown in the greenhouse. Under this classification, the Japanese varieties, such as Fujisaka 5 and Norin 20 (Appendix), do not fall under any category because they have a short BVP and short PSP. Also, at least four photoperiods (10, 12, 14, and 16 h) are needed to classify the cultivars. A more practical grouping could be as follows (using also the length of the BVP and PSP). 1. Photoperiod nonsensitive . very short PSP (less than 30 d) and BVP varying from short to long. 2. Weakly photoperiod-sensitive . arked increase in growth duration when photoperiod is longer than 12 h; PSP may exceed 30 d, but flowering occurs under any long photoperiod. 3. Strongly photoperiod sensitive – sharp increase in growth duration with increase in photoperiod; no flowering beyond critical photoperiod; BVP usually short (not more than 40 d). Cultivars tested under only two photoperiods, such as 10 and 14 h, can also be classified according to these groupings (1 1). Agronomists and farmers would tend to use these groupings. The flowering response of the rice plant to photoperiod 23 Inheritance of vegetative growth duration The inheritance of the duration from seeding to heading in cultivated rices has been studied by many research workers, but the findings have resulted in diverse interpretations. Three categories of genetic postulates were generally offered: 1) monogenic or digenic control of heading date, with earliness dominant to lateness; 2) monogenic or digenic control of flowering date, with lateness being a dominant trait; and 3) multiple-factor inheritance in which the F 2 population showed a continuous and often unimodal distribution and in which the same population might produce a bimodal distribution when grown in a different season (44, 509). In experiments where photoperiod sensitivity was recognized, delayed flowering under a long photoperiod was generally inherited as a monogenic or digenic dominant trait (38, 242, 406, 424, 567). In several crosses involving distantly related parents, sensitivity to photoperiod appeared to be a recessive trait (242, 406). The continuous and transgressive segregation in several F 2 populations involving photoperiod-insensitive parents was ascribed to multiple genes, which indicated dominance of earliness (41, 95, 96, 97, 333, 389, 469, 554). However, in crosses among varieties in Yunnan Province in China, photoperiod sensitivity appeared to be a recessive trait in some F 1 hybrids (252). Some of the divergent interpretations just mentioned resulted partly from failure to recognize the composite nature of the vegetative growth period from seeding to panicle primordium initiation, partly from failure to control the interaction of the environmental factors (mainly photoperiod and air temperatures) and the different genes controlling the vegetative growth period, or from failure to relate the phenotypic expression with the revailing environment. Recent studies at IRRI (48, 161, 162, 163, 164, 165, 167, 168, 249) have demonstrated physiologically and genetically the feasibility of partitioning the vegetative growt