Impact of Waterlogging on Plants

Impact of Waterlogging on Plants Abstract: This review will try to illustrate some of the impacts that waterlogging has on plants, in monocotyledons dicotyledons. The review includes, a general introduction into the impact of anaerobic/waterlogged soil condition on plants, quoting from different sources in this field. Then it focuses on five plant species of global interest or importance, Barley, Tomatoes, Soy Bean, Cotton and Rice, showing the effect of waterlogging on each, quoting journals and experiments done by fellow scientist .The topic of research into waterlogging is vast, with thousands of journals and experiments on countless plant species, so Im focusing on just five. Flooding and submergence are major abiotic stresses and rank alongside water shortage, salinity and extreme temperatures as major determinants of species distribution worldwide. Plants adapt to their ever-changing environment in many ways, leading to a wealth of growth forms of varying complexity (Visser et al, 2003). A major constraint resulting fr om excess water, at least for poorly adapted species, is an inadequate supply of oxygen to submerged tissues; diffusion of oxygen through water is 104-fold slower than in air (Armstrong Drew, 2002). In addition to the threat of oxygen deficiency, excess water also leads to other changes in the soil that influence plants; levels of the plant hormone ethylene (Smith Russell, 1969; Jackson, 1982), and products of anaerobic metabolism by soil micro-organisms (e.g. Mn2+, Fe2+, S2-, H2S and carboxylic acids) can accumulate (Ponnamperuma, 1984; McKee and McKevlin, 1993). It was suggested by (Zhou, Li, and Mendham, 2007), that Waterlogging tolerance is likely to be a complex trait which is related to many morphological and physiological traits that are under strong environmental influence. Introduction: Waterlogging can lead to countless physiological and developmental problems as mentioned in many publications, journals and experiments. It was suggested by setter co-workers, 1999 that, Stress on plants imposed by flooding of the soil and deeper submergence constitutes one of the major abiotic constraints on growth, species distribution and agricultural productivity. Waterlogging is estimated to reduce yields on average by 20 to 25%, but the loss may exceed 50% depending on the stage of plant development (Setter et al., 1999). 50 % loss in agricultural yield can be catastrophic in the future, especially for developing countries, which is why, research into waterlogging is crucial for agricultural sustainability and food security. The general effect of waterlogging on plants ranges from physiological, developmental and metabolic effects which are mentioned in a few publications. Waterlogging is a major problem restricting the plant growth by leading to oxygen deficiency around roots and rhizomes, and consequently it can be fatal because aerobic respiration ceases and levels of energy-rich adenylates drop rapidly resulting in dramatic decrease in ion uptake and transport (Huang et al, 2003; vartapetian et al, 2003) as quoted in (Changdee., et al, 2008). When soil is saturated with water, gas diffusion is reduced. Consequently one of the main effects of flooding is a lower pool of available O2 in submerged plant parts. This decline in O2 is heightened by aerobic processes taking place in the root zone of plants. Accordingly anoxic conditions develop, leading to reduction in ATP production and consequent decrease in root metabolism. The decline in available energy can subsequently reduce other active cellular processes such as nutrient uptake, osmotic adjustment or regulation of cytoplasmic pH (Probert Keating, 2000). Waterlogging resulted in visible yellowing and premature senescence of leaves, and greater decline in relative water content, chlorophyll content, and membrane stability (Sairam, et al, 2009). The majority of plants respond negatively to waterlogging whilst some plants respond positively. Discussion: Plants throughout the years have adapted different ways to minimize damage caused by waterlogging. All plants poses survival mechanisms which are of a complex nature, and differing between some species. Plants also differ in the way they respond to anaerobic or anoxia soil conditions, some are extremely tolerant, some very sensitive and some in between. Even species that are susceptible to poorly aerated conditions possess metabolic and molecular responses that lengthen survival time from a few hours to several days. All plant species synthesize so-called anaerobic proteins that enable an oxygen-independent energy-generating metabolism to proceed where fermentable substrates are available (Subbaiah Sachs, 2003). Prevention of the build-up of potential phytotoxins is another mechanism that enhances plant survival under flooded conditions. A specific type of hemoglobin (phytoglobin) may play such a role by detoxifying nitric oxide formed during hypoxia of root tissues. Alternatively, phytoglobin may also regenerate NAD+, thereby serving as an alternative to fermentation as a source (Dordas et al., 2003). Impact of waterlogging on five plant species Barley: In barley Waterlogging inhibits the uptake of N which leads to the decrease of N concentration in shoots of barley seedlings (Drew and Sisworo, 1977). Pang et al. (2005) found that both shoot and root growth was negatively affected by waterlogging. As waterlogging stress developed, chlorophyll content, CO2 assimilation rate, and maximal quantum efficiency of photosystem II (variable fluorescence/maximum fluorescence) decreased significantly, with cultivars showing less yellow leaf percentage having less adverse effects (Pang et al., 2005). A decrease in nitrogen uptake, fluorescence leads to decreased leaf area index (LAI) and decreased yields. Oxygen deficiency in the rooting zone occurs under waterlogging conditions, the lack of O2 can severely damage the root (Drew, 1997) . Soil waterlogging usually influences barley growth in a negative way, the inhibition of N uptake, and the consequent redistribution of N within the shoot, are important contributory factors in the early senescence of leaves and the retarded growth of shoots in flooded plants (Drew and Sisworo, 1977). A decrease in the N concentration in shoots of barley (Hordeum vulgare L.) seedlings can occur rapidly after the onset of flooding and precede leaf chlorosis (Drew and Sisworo, 1977; Wang et al., 1996) and consequently reduces shoot and root growth, dry matter accumulation, and final yield (Kozlowski, 1984; Drew, 1991; Huang et al., 1994a,1994b; Malik et al., 2002). Roots are also injured by O2 deficiency and metabolic changes during acclimation to low concentrations of O2 (Drew, 1997). Tomatoes: in tomatoes it was reported that; Enhanced ethylene production and leaf epinasty are characteristic responses of tomato (Lycopersicon escukntum Mill.) to Waterlogging. It has been proposed by (Bradford Yang, 1980) that this results from the synthesis of the immediate precursor of ethylene, 1-aminocyclopropane-I-carboxylic acid (ACC), in the waterlogged roots, and its export in the transpiration stream to the shoot, and its rapid conversion to ethylene gas as stated in (Kent, et al, 1982). Soybean: It has been reported that cereals are generally more tolerant to flooding than legumes (Crawford, R.M.M, 1977) as quoted by (Russel, Wong Sachs, 1990). Cotton: Waterlogging of cotton has been reported to cause a reduction in root growth and nutrient uptake (Letey et al., 1962; Huck, 1970; Hocking et al., 1987), leaf area and photosynthesis (Hodgson, 1982; Meyer et al., 1987; Sahay, 1989) and dry matter accumulation and fruiting (Hodgson, 1982; Hocking et al., 1987). Rice: (Oryza sativa), is one of the most interesting monocotyledonous plants in my opinion, rice is one of the few plant species that can adapt too tolerate very low concentrations of oxygen in the soil and reacts positively to waterlogging without negative effects on plants growth and development. Rice grows better than any other plant in the same waterlogged conditions. In two experiments by Perata on rice seed germination showed interesting results.

Character Development in Edward Abbeys The Monkey Wrench Gang Essay

Character Development in Edward Abbey's The Monkey Wrench Gang    Search and Rescue, Utah State Police, and Bishops of the Church of Latter-Day Saints chase a group of bridge destroying, billboard burning, bulldozer mutilating eco-terrorists through the desert of the Southwest. The group known as the Monkey Wrench Gang consists of four very different characters: Seldom Seen Smith, also known as Joseph Smith, George Washington Hayduke, Doctor A. K. Sarvis, and Bonnie Abbzug. Each character has his own opinion of why nature needs to be saved. The group decides to make their mark on nature by "taking care" of the different machines, roads and bridges that are destroying it. With all the destruction the gang is causing, being caught is expected. However, the gang narrowly escapes the law numerous times. After finally giving in to the pressures of being good citizens and serving time in jail for destroying public property, the gang reunites for their final destructive mission: Glen Canyon Dam. Edward Abbey, author of The Monkey Wrench Gang (1975), uses language, appearances, actions and opinions to make each character likable to the conservative reader. Abbey uses his strong feelings about the beauty of the Southwest to shape the opinions of each of his characters. Doc Sarvis, a medical surgeon from Albuquerque, has no strong or lasting relationships. "His few close friends were always sent away, returning rarely, the bonds of affection no stronger than the web of correspondence" (12-13). Doc?s closest friend, and coworker, is Ms. Bonnie Abbzug. Doc and Bonnie spend most of their downtime destroying billboards with economic meanings, because "Somebody has to do it" (43). Such billboards worthy of destruction read "Marine Corps bu... ...ng nurse on the right buttock and shambled on shaky hind legs out the side door up the alleyway . . . into the padded darkness of the nearest bar" (213). With Smith being the logical member of the gang, "he listens with the concentrated intensity of a buck in hunting season" (337). When he finally hears something, "he stops. Suddenly. Doc, Bonnie and Hayduke stumble into his rear like the Three Stooges, three clowns in a silent movie" (336). While reading The Monkey Wrench Gang, many images appear in one?s mind. The uses of Edward Abbey?s skill of developing characters through language, appearance, actions and opinions make this novel more enjoyable to read. The shaping of each character persuades the reader to believe that, "Oh my desert, yours is the only death I cannot bear." Work Cited Abbey, Edward. The Monkey Wrench Gang. 1975. New York: Avon Books.

Fear and Loathing in Las Vegas Essay

Literature is considered a mirror of the society. The pool of content in literary writing stems from the environment in which the writer is placed. A writer will use this environment to advance his/her views of the society and at the same time drive into the audience/readers important information that he/she wishes to pass. Hunter S. Thompson has used his creativity in the novel Fear and Loathing in Las Vegas written in the 1960s to reflect on American society with Las Vegas as the point of reference. Fear and Loathing in Las Vegas describes the American society as hypocritical. The Duke and Gonzo attend a conference on narcotics and dangerous drugs. The theme of the conference is slated as an appeal for knowledge sharing on drugs between those with knowledge on drugs and those that do not. Their attendance is hypocritical in that they have already decided that they were not going to offer their services at the conference. Thompson on page 143 notes that Duke and Gonzo had made it clear that they would be crazy to try any teaching at the conference and they would rather sit and enjoy their drugs. Furthermore, the police who are tasked with law enforcement are also hypocritical, instead of enforcing laws on drugs and alcoholism they engage with criminals in committing crimes. This is illustrated by the police officer from Georgia. Secondly, the American society is as a blacked out society. Drugs, alcoholism and black market enterprises characterize a blacked out society. A black market society is a consumer based society characterized by both legal and illegal business the duke and the attorney are not drug dealers but heavy consumers. As soon as they get to Mint hotel the Attorney orders four shrimp cocktails, four club sandwiches, quart rum and fresh grape fruits. He says they will need to have all they can get. There stay in Las Vegas is characterized by heavy drug abuse and alcoholism. The sorry state of this vices forces the administration to organizes conference to tackle issues of drugs and alcohol dubbed In addition, Fear and Loathing Las Vegas reveals racist nature of the American military and the decay of moral values. This is portrayed in a copy of the Las Vegas Sun newspaper. â€Å"†¦she was just a slope anyway.† This is in reference to killing of Asiatic origin person. His killing is considered right for simple reason that he from the race of the enemy camp. A ‘slope’ referred to Asiatic community. The massive killings during the Vietnam War were ironically regarded as success by the American government. As the Duke continues to read the newspaper, a small article talks about how Mohammed Ali has a final appeal of a case in court which he had been sentenced to five years in prison for refusing to kill â€Å"slopes.† This illustrates the moral decay of the society. A criminal was likely to get a shorter jail term than a person who had refused to join the military and aid in killings. What is right is considered a serious offence. Consumerism and capitalist culture has been embraced in Fear and Loathing in Las Vegas. This is well brought out by the two protagonists in the novel. The lifestyle of the Duke and his attorney on the journey to Las Vegas is characterized by heavy spending on drugs, accommodation, transportation and gambling. Duke says their car trunk looked like a police narcotics lab (Thompson 4). This shows they had bought so many expensive drugs which the writer goes ahead to acknowledge that they did not actually need but for the fun of it. Moreover, the two protagonists are searching for American dream using a fascinating car â€Å"†¦we are looking for the American dream†¦that is why they gave us this white Cadillac† (Thompson 164). This demonstrates the capitalist nature. The car has to be a Cadillac which was a status car of the might in the society. Lastly, the novel’s central theme revolves around the American dream. The American dream is an idea stating that success comes through hard work. However, the dream is a dying one which has not materialized because of the society’s greed, selfishness and corruption as depicted in Fear and Loathing in Vegas by Thomson. Drug business, prostitution and gambling have replaced legal businesses in Las Vegas. Law forces have been tangled up in this game as they watch this acts being committed for a few pennies from the dealers. The picture of a crowd of Las Vegas residence in a casino at early hours of the morning gives more dimensions to the American dream. Emerging from a casino having won seems to epitomize what the society feels about the American dream. Patriotism among American citizens in the pursuit of this dream cannot be disputed despite being portrayed negatively. The Duke says â€Å"†¦I will have a natural American car or nothing at all† (Thompson 104). This illustrates pride in American products as opposed to products from other countries. Fear and Loathing in Las Vegas by Thompson Hunter S. arguments have negatively portrayed the American society in the 1960s and 1970s. Drugs and alcohol abuse, racism, hypocrisy, failed institutions and the dying American dream continue to daunt the image of the Las Vegas society. However all is not lost as the issues addressed have continued to be a point of reference not only to the Americas past but the future ambitions. Thompson plays his role as an author in bringing into public what is ethically wrong or right. Reference Thompson, Hunter S. Fear and Loathing in Las Vegas: A Savage Journey to the Heart of the American Dream. London: Flamingo, 1972 Source document

The Origns of Marijuana - 726 Words

The origins of The Cannabis use began in the Chinese Emperor Shen Nung in 2727 B.C. While in the Middle East, the use of cannabis spread throughout the Islamic Empire to North America. In 1545, the cannabis spread through the county; Chile began to use the drug as a fiber. Consequently, cannabis grows throughout tropical and humid parts of the world. The seeds have been used as animal food, fiber for hemp rope and oil as a vehicle for paint (Cannabis, Coca, and Poppy). Therefore, Marijuana should be removed from the criminal justice system. Legalizing and regulation marijuana can bring cash crop under the criminal justice law, bring in jobs, medical use, and overall create economic opportunities to The United States of America. There has been reports of marijuana being less harmful than alcohol or tobacco. According to the British research foundation two deaths worldwide can be directly caused by marijuana, yet 150,000 people die from alcohol and tobacco (â€Å"Marijuana Less Harmful). Moreover, CNN discusses the ongoing debate of marijuana legalization which concluded that alcohol is the most used addictive substance in the USA. The National Institute on Alcohol Abuse and Alcoholism documented that about 17.6 people suffer from alcohol abuse which causes withdrawal symptoms of anxiety, depression, insomnia, headaches, nausea, and so on. While, marijuana symptoms are not fully understood, but the NSDA states 9% of people who smoke marijuana became addicted to it. The