Innumerous plant species in the Amazon forest may be an excellent alternative to meet society's demand for natural products. This work aimed to determine and characterize the pattern of allelopathic activity in species of the Leguminosae family, according to species variation, extract source, and receptor plant sensitivity. Bio assays of seed germination and radicle and hypocotyl elongation were developed under controlled conditions. The results indicated that the species studied do not present a similar pattern regarding the potential allelopathic effects; however, there is a hierarchy concerning the intensity of the global effects, with the allelopathic inhibitory potential being more extensive and effective for the species Bauhinia guianensis, Bowdichia virgiloides, Parkia pendula and Platimenia reticulate, and more restricted and effective for Bauhinia macrostachya. The plant fraction factor showed differences in the activity pattern, with the leaves being the main source of allelochemicals for most species, and the roots, for Bauhinia macrostachya and Inga edulis. In terms of response pattern of the receptor plants, radicle elongation is more sensitive to the effects of the extracts, with hypocotyl elongation being the least sensitive. The effect of the extracts was more intense for Mimosa pudica. These results confirm the importance of the Amazon forest as a source of chemical compounds of interest to mankind, which by itself justifies its preservation.
allelopathy; extracts; weed; inhibition
