Brazilian Journals Publicações de Periódicos e Editora Ltda.
Abstract
Allelopathic and cytotoxic effects inform possible changes due to changes in growth and can be studied using different plant species. The objective of this work was to evaluate the allelopathic and cytotoxic effect of the aqueous extract of Conyza bonariensis on horticultural species. The experiment was carried out in the Phytotechnics Laboratory at Universidade Estadual de Santa Cruz, Ilhéus, Brazil. Lettuce seeds (Vera) and melon seeds (Ouro) were evaluated in germination tests and phytotoxicity. C. bonariensis leaves, stalk, and flowers were selected and placed in a drying oven at 60 °C for 72 h and then weighed for extract aqueous at concentrations of 1, 3, 5, 7 and 10%. Were evaluated germination test (%), germination speed index (GSI), primary root and shoot length of seedlings. For the cytotoxicity test, the onion model was in five concentrations 0, 0.5; 1; 1.5, and 2% where the mitotic index and cell numbers in the cell division phases (prophase, metaphase, anaphase, telophase) were evaluated. The data were subjected to analysis of variance, and the means compared using Scott-Knott test at 5% probability. The results showed that C. bonariensis aqueous extract did not affect germination, germination speed index, and shoot length in melon, but showed phytotoxic effect on seedlings with decreasing root length. The aqueous extracts of C. bonariensis inhibited seed germination and primary root development and shoot length in lettuce. Chromosome disorganization on the equatorial plane during metaphase and chromosome breakage was observed in the mitotic process of onion roots in C. bonariensis aqueous extract concentrations. Higher concentrations of the extract have allelopathic activity with inhibitory action of cell division
