The Effect of the Allelopathic Compounds of Encelia Farinosa on Desert Native Annuals and Non-Native Seed Germination: An Experiment
Abstract An experiment was conducted to determine the effect of the allelopathic compounds of Encelia Farinosa (brittle bush) on desert native annuals and non-native seed germination. The experiment was set up by putting native wild flower seeds in six Petri dishes and lettuce seeds in six different dishes. To three of each dish containing the different seeds, water was added as a control. To the three other dishes, a prepared brittle bush tea (filtered ground brittle bush leaves and water) was added. After a week’s time, the number of germinated seeds in each dish was counted. The results showed that the allelopathic compound in brittle bush did have a significant effect on both the lettuce seeds and the native wildflowers when compared to their respective controls. However, the results showed no significant difference between the two means of the native seeds with brittle bush tea and the lettuce with brittle bush tea. This led to the rejection of our hypothesis and acceptance of the null hypothesis which stated that no significant difference existed between the two means.
Introduction
In the natural world, plants are in constant strain of exploitation and competition. Through the evolutionary process, plants have developed many ways to help cope with various environmental stresses. Some plants overcome environmental strain by growing taller or deeper to extract as many resources as possible. Others resort to numbers and try to overwhelm their predators and competitors by population size. However, possibly the most interesting method many plants take is the use of chemicals to kill or inhibit predatory herbivores and competing plants. Plants that resort to this method of defense are known as allelopathic and the chemicals used by these plants are called secondary metabolites. Nowhere is the struggle for resources more vital than in the desert. The use of secondary metabolites in desert plants is believed to be one of the most common defense mechanisms in
Introduction
In the natural world, plants are in constant strain of exploitation and competition. Through the evolutionary process, plants have developed many ways to help cope with various environmental stresses. Some plants overcome environmental strain by growing taller or deeper to extract as many resources as possible. Others resort to numbers and try to overwhelm their predators and competitors by population size. However, possibly the most interesting method many plants take is the use of chemicals to kill or inhibit predatory herbivores and competing plants. Plants that resort to this method of defense are known as allelopathic and the chemicals used by these plants are called secondary metabolites. Nowhere is the struggle for resources more vital than in the desert. The use of secondary metabolites in desert plants is believed to be one of the most common defense mechanisms in
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