Allelopathy Affects Germination of Radish Seeds

Introduction This experiment is designed to test the allelopathy of two different treatments, Eucalyptus (Eucalyptus cinerea) and Lemon (Citrus limon). The two treatments will be tested on radish seeds (Raphanus sativus) to investigate the effect of the treatments on the germination of the radish seeds. Allelopathy is the beneficial or harmful effects that one plant has on another plant by the release of chemicals. Allelopathy studies the interactions among plants, fungi, algae and bacteria with the organisms living in a certain ecosystem, interactions that are mediated by the secondary metabolites produced and exuded into the environment (Francisco A Macías, José MG Molinillo, Rosa M Varela, Juan CG Galindo 2007). The plants use allelotoxins, which are an allelochemical produced by one plant that is toxic to another plant, to help them compete for space. Often these chemicals inhibit seed germination and root growth of young neighboring plants with less effect on mature plants (Shimabukuro and Haberman 2006).

Allelopathy is very a useful strategy for plants. It is very important in agricultural society to eliminate weeds, pests, and insects. Plants use allelopathy to assure them a spot in nature. I am trying to see which one of these plants inhibits the germination of radish seeds the most. Putnam (1984) reported that eucalyptus species released volatile compounds such as benzoic, cinnamic and phenolic acids, which inhibit growth of crops and weeds growing near it. Eucalyptus is a widely well-known allelopathic plant. I believe that Eucalyptus will allow the least amount of germination of radish seeds between Eucalyptus, Lemon, and a control.

Methods The method used for this experiment was very easy to set up. Five different lab groups performed the same experiment. Three petri dishes is the first thing I needed. I placed a piece of paper at the bottom of each dish and found the exact center and made a mark. Next I put ten radish