Resumo

SOUZA FILHO, Antonio Pedro S.; RODRIGUES, Luis Roberto A.  e  RODRIGUES, Teresinha Jesus D.. Allelopathic potential of tropical forages: effects on pasture weeds. Planta daninha [online]. 1997, vol.15, n.1, pp. 53-60. ISSN 0100-8358.  http://dx.doi.org/10.1590/S0100-83581997000100007.

Aqueous extracts from seeds, aerial part and roots of grasses Brachiaria humidicola, Brachiaria decumbens and Brachiaria brizantha cv. Marandu and legumes forage Calopogonium mucunoides and Stylosant hes guianensi s cv. Mineirão were prepared in a concentration of 10% (w/v), to evaluate the allelopathic potential effects on seed germination and radicle elongation of the pasture weeds: Desmodium adscendens, Sida rhombifolia and Vernonia polyanthes. Seed germination was monitored in ten-day periods, with daily countand elimination of seed germination. At the end of the ten-day periods the radicle was measure d. The osmot ic potential effects were isolated by calculation. The donor species showed allelopathic potential that varied in function of donor and receiver species. Brachiaria brizantha and among grasses and Calopogonium mucunoides among legumes were the species that promoted the reduction more intensively on seed germination and radicle elongation of the receiver species. The aerial part of the donor species was the main source of water soluble allelopathic potential compounds. Independently of the donor species, D. adscendens and S. rhombifolia were the weeds with the greatest sensibility to allelopathic potencial effects from donor species, while V. polyanthes showed more tolerance.

Palavras-chave : Aqueous extracts; seeds; aerial part; roots.