Testing the Effects of Allelopathic Substances on Casuarinas Bishophia Melaleuca and Schinus

Testing the Effects of Allelopathic Substances on: Casuarinas, Bishophia, Melaleuca, and Schinus
Justin Nighan
Dept. of Biology, University of Miami, PO Box 249118, Coral Gables, FL 33146
[email protected]
Allelopathy occurs when organic substances with autotoxic or antibiotic properties from one plant inhibit the growth of other plants nearby. This phenomenon is best developed in perennials and woody plants of arid environments. These inhibitory substances can be released in three ways: passed directly in the soil form living tissues, leached from living of dead shoots, or passed though the air to be deposited on the surfaces of other plants. The goal of this study is to test the effects of allelopathic substances on four species of plants: casuarinas, bishophia, melaleuca, and schinus. Thirty seeds of each species of plant were planted in the filter paper of a Petri dish. The filter paper is saturated with homogenized extracts of the plants. A control group was set up having the filter paper saturated with water only. After a week the germinating seeds were counted in each dish and a Z-test was preformed on the data collected. The null hypothesis states that there is not a decrease in germination as a result of the homogenized extracts. The results are that all four species of plant fail to accept the null hypothesis. The conclusion can then be made that there is some type of effect on the plants tissue that results in reduced germination. The Petri dishes in this study were heavily infested with mold, which may or may not have affected germination.