Estudo do potencial alelopático do ácido salicílico sobre as plantas alvos: leiteira (Euphorbia heterophylla) e picão preto (Bidens pilosa)

Abstract

Salicylic acid has as one of its characteristics, the allelopathic potential, besides being a synthesizable product. It can replace other substances that have the same characteristic but are difficult to obtain. Used as a preliminary test for determination of concentration range, which significantly and negatively influences target plants. To study the allelopathic potential of salicylic acid, a bioassay was performed in a BOD incubator. Seedling growth was evaluated by measuring root, hypocotyl, and seedling length. The seeds used as target plants in this test were the “leiteira” (Euphorbia heterophylla) and the “picão preto” (Bidens pilosa). This test was performed for 12 days, and measurements were taken every 3 days, for concentrations of salicylic acid 1000, 750, 500, 250, 125 and 62.5 ppm and control (distilled water). Data were initially submitted to the Kolmogorov-Smirnov normality test and subsequently to the two-way ANOVA tests with repetition, Tukey and normal P-Plot residue. Based on the results obtained, it was possible to observe that several concentrations presented significant diferences, ie there was a difference in the lengths. There was a sharp reduction in the growth of both species. Highlights were for concentrations of 750 and 1000 ppm for Euphorbia and 500, 750, and 1000 ppm for Bidens. However, between these groups showed no significant difference. Root length was the most negatively affected part, with a reduction for E. heterophylla from 10.2 cm to 0.7 cm and for B. pilosa 4.1 cm to 0.6 cm. Euphorbia was the one that showed interference, with about 93.14% reduction, compared to the control. With these results, it is possible to determine a better concentration range and after testing with other substances, formulate a product with bioherbicidal characteristic.