Atividade alelopática de extratos foliares de malpighia glabra l. em bioteste com lactuca sativa L.

Abstract

Allelopathy is a process derived from the secondary metabolism of plants, where the plant releases chemical substances, which may have mechanisms of direct or indirect action on the development of other plants, resulting in an inhibitory effect or a stimulating action. The species Malpighia glabra L., popularly known as acerola, is widely consumed in Brazil, with great economic and nutritional potential, due to its high vitamin C content. The leaves have coumarins, flavonoids, phenolic acids and amino acids (asparagine, proline, alanine and methionine). The presence of these chemical constituents makes acerola a species with allelopathic potential. The objective of this work was to evaluate the allelopathic activity of foliar extracts of M. glabra in a biotest with Lactuca sativa L. Where we obtained dry, aqueous and hydroethanolic extracts, to carry out studies of the phytotoxic and cytogenotoxic effects on the germination and initial growth of L. sativa. The test solutions were prepared at concentrations of 5, 10, 20 and 40 mg.mL -1

, using distilled water as a control group. The evaluated parameters were: initial and final germination percentage, germination speed index, allelopathic effect index, shoot length, root elongation, mitotic index and frequency of chromosomal abnormalities. Results showed that extracts at higher concentrations caused abnormalities in cell division and reduced germination performance of lettuce seeds.

Abnormalities included micronuclei, bridges in anaphase and telophase, c- metaphases, stickiness, missing chromosomes, and chromosome delay in anaphase

and telophase. In addition, the extracts also caused changes in the enzymatic activity of lettuce seeds. This suggests that the use of these extracts may have negative effects on plant growth and development.