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Unformatted text preview: An Investigative look at Resource Competition and Allelopathy among Lettuce Seeds Yontii Wheeler Date Due: Friday March 12, 2010 Dr. Doebel BISC 012 Allelopathy and Resource Competition were the main subjects of the investigation held for this lab. Resource Competition and Allelopathy are used to describe interactions between plants. Allelopathy is simply an indirect or direct effect by one plant on another. This includes a harmful or beneficial interaction and the effect comes through the production of chemical compounds that are emitted into the environment. Sometimes, allelopathy is introduced in response to resource competition. Therefore, when two plants are competing for resources, in allelopathic response would be for one plant to release a chemical compound that caused the other plant to be negatively affected and increase productivity for the plant emitting the chemical . Most of the time, allelopathy involves a plant releasing a chemical into the environment that inhibits the growth of the other plant that was at first most likely competing for resources with it. Allelopathy includes complementary affects as well as inhibitory ones, however, in this lab, these biologists focused on the inhibitory affects (Kebede). In order to truly understand allelopathy in response to resource competition, these psychologists conducted a lab where we looked at lettuce seeds and the different interactions they had with one another when placed in different environments. Lettuce seeds were chosen because they grow faster than most other plants and due to the nature of the experiment, we didnt have much time to wait for other types of seeds to grow. This was done to detect when allelopathy occurs, or what environmental conditions trigger it. Allelopathy is strongly affected by environmental factors so in this lab, most of the environmental factors such as sunlight and water in some instances was kept the same for all Petri dishes. Shade, drought, and nutrient amounts, affect and can induce allelopathy, however, in this lab, drought was tested in order to determine what amounts or lack thereof, triggered allelopathic results. The results of this experiment can be seen as weights of dishes before and after watering and descriptions of the growth of the seeds when placed in different environments. There were controls used, and although this biologist and her lab group tried to alleviate confounding factors, it is this biologist, as well as the other lab members belief, that this experiment had a lot of errors that most likely affected the outcome. Another situation tested was the growth of lettuce seeds in the presence of chemicals secreted by plants when involved in allelopathy (Roger Del Moral, 1997). This lab group tested the growth of lettuce seeds with the same amount of water and different amounts of mustard oil (has allyl isothiocyanate, a chemical secreted by plants in allelopathy and found in mustard oil) as well growth of seeds with varying amounts of water (Shettel, Balke, 1983). The oil) as well growth of seeds with varying amounts of water (Shettel, Balke, 1983)....
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This document was uploaded on 10/27/2011 for the course BIO 10002 at GWU.
- Fall '10