Avaliação de extratos de Tithonia diversifolia (Hemsl.) A. Gray sobre a germinação e desenvolvimento inicial de Lactuca sativa L. e Cucumis sativus L.

Abstract

Finding alternative inputs both for fertilization and for the control of spontaneous species and insects is one of the bottlenecks related to the development of agroecological agriculture. The growing need for alternative herbicides drives the search for natural compounds that act as allelopathic. In this sense, the work aims to evaluate the biological effect of extracts of Tithonia diversifolia (Hemsl.) A. Gray (Asteraceae) on germination and initial development of plant species. Therefore, two experiments were carried out on a laboratory scale. In the first one, the effect of different concentrations of aqueous extract of T. diversifolia on germination and initial development of Lactuca Sativa (lettuce) was evaluated, through which it was concluded that aqueous extracts of T. diversifolia at concentrations between 5% and 20% do not affect the final germination of lettuce seeds, but they cause an increase in TMG, decrease in IVG and anomalies in germinated seedlings. In the second experiment, the biological effect of the aqueous extract of different plant parts of T. diversifolia on the germination and initial development of seeds of L. sativa and Cucumis sativus L. (cucumber) was evaluated. development impaired by plant extracts of T. diversifolia that inhibited the growth parameters of L. sativa and C. sativus in the following order: flowers > aerial part > leaves > stems. Based on the results, it is evident that germination is less sensitive to allelochemicals than seedling development. T. diversifolia affected the development of seedlings, probably because it contains bioactive substances, these results can serve as a basis for future research that aims to test the use of T. diversifolia for the production of bioherbicides.