Estudo dos efeitos alelopáticos de extratos obtidos de Eucalipto (Eucalyptus sp) em culturas de alface (Lactuca sativa L)

Abstract

Allelopathy studies the interactions between plants through the release of secondary metabolites into the cultivation medium, which interact with other plant species and can cause beneficial effects such as increased protection of aerial parts against the incidence of insects, or harmful effects such as growth interruption. . These effects are observed in agroforestry systems; however, it has become the object of study for the possibility of developing molecules as an aggregate in the production of agricultural pesticides or direct use as lower impact management. The present work aims to identify chemical substances capable of causing allelopathic effects through qualitative mechanisms using chemical reactions and test the effects of allelochemicals on lettuce seedlings. The parts of the Eucalyptus plant were purchased from local stores in Uberaba-MG and were washed, dried and calculated for humidity. The extraction and identification of classes of chemical compounds was carried out through chemical reactions. Furthermore, solutions containing allelopathic substances were prepared and applied to lettuce seedlings in a randomized block design. Plant size was measured on the sixth day after applying the solutions to the plants. The results were compared using ANOVA and Tukey test at 5% significance. Through the reactions, the presence of several classes of substances was identified, such as: flavonoids, alkaloids, phenanthrenes and tannins in large percentages of the tests. These substances influenced both the growth and development of seedlings, generating effects in parts of the blocks. Thus, the results show that these substances generate effects on these plant species and can be used as a form of management with less impact and production of assets and products that are less aggressive to the environment.