Atividade alelopática de extrato aquoso de raízes de malva branca (Sida cordifolia L.) na germinação e crescimento inicial de hortaliças.

Abstract

Allelopathy refers to the natural release of inhibitory substances by certain plants capable of interfering with the growth of other in the environment. This study aimed to identify the allelopathic activity of aqueous extract of S/da cora/fo//a L. roots, germination and initial growth of lettuce seedlings, green onions and peppers. The study was conducted at the Seed Analysis Laboratory and Seedlings of the Center for Science and Technology Agrifood the Federal University of Campina Grande, in Pombas-PB. Were employed two bioassays (germination - l and initial growth - 11) in a completely randomized design with four replications of 25 seeds per treatment for the bioassay of germination and ave replicates with 10 seedlings for the initial growth bioassay. The aqueous extracts were obtained from S/da cora/áo//a L. roots of plants of previously dried and ground in a forced air circulation oven, adding 10 ml of deionized water for every gram of the obtained powder, the extract was filtered and stored for 48 hours. Before application of the extract, it was diluted with deionized water to obtain the following concentrations: 20, 40, 60 and 80%, and still used the concentration of 0% (deionised water) as control. The solutions at different concentrations were measured osmolarity and then PEG 6000 were prepared in the same osmolarity of the extracts to obtain a contrai of the osmotic effect on the germination and growth of the target species under study. Evaluations consisted of the germination test, first count and germination speed index, average time of germination and allelopathic effect index for the bioassay l and length of root and short and total dry mass for the bioassay 11. Data were subjected to analysis of variance and polynomial regression and significant data, adjusted equations in arder to analyze the behavior of variables with increasing doses of the aqueous extract of S/da cora/ão//a L. The aqueous extract of S/da cord/áo//a L. roots not interfered on the germination of lettuce seeds, green anion and pepper, however, showed allelopathic activity on the early development of these seedlings and the effects have proved generally dose-dependent. But the effect of aqueous extract of S/da cord/ão//a L. on the initial development of lettuce seedlings, green onions and peppers are not osmotic or hydrogen ion nature.