Potencial alelopático do angico-vermelho (Anadenanthera peregrina (L.) Speg.): efeitos sobre a germinação de sementes e ciclo mitótico de plântulas de alface (Lactuca sativa L.) e canafístula (Peltophorum dubium (Spreng.) Taub.)

Abstract

To evaluate the allelophatic potential of "angico-vermelho", water extracts seedlings and adult plant leaves at concentrations of 0%, 2%, 4%, 8%, and 16% were prepared, and applied on lettuce and "canafístula" seeds. Evaluations were performed for germination, GRI (germination rate index), of root and hypocotyl lenght, and cytogenetical analysis of meristematic region of roots. It was found that the leaves extracts of "angico-vermelho" inhibited all the analised characteristics, mainly at the highest concentrations of the extracts, although a small stimulus at the 2% concentration on germination, GRI and hypocotyl lenght was observed. It was observed reducition in number of dividing cells, reduced mitotic index and abnormalities such as colchicinic metaphases, metaphases with sticky chromossomes, side metaphases with unconnected chromossomes, bridges and fragments at anaphase and telophase, fragmented interphasic nuclei and telophases with condensed chromossomes. It was also observed that morphological changes in lettuce seedlings was extract concentration dependent.