ALLELOPATHY OF OATS .1. ASSESSMENT OF ALLELOPATHIC POTENTIAL OF EXTRACT OF OAT SHOOTS AND IDENTIFICATION OF AN ALLELOCHEMICAL

The allelopathic potential of oat (Avena sativa L.) extracts was inves tigated under laboratory conditions. The ethyl ether-, acetone-, and w ater-soluble fractions obtained from the extract of oat shoots inhibit ed the germination and growth of roots and hypocotyls of lettuce (Lact uca sativa L.). The inhibitory activity of the water-soluble fraction was maximum, followed by that of ethyl ether-soluble and acetone-solub le fraction. An active principle of the water-soluble fraction was iso lated and its structure was determined by spectral data as L-tryptopha n. L-Tryptophan inhibited the growth of hypocotyls and roots of lettuc e seedlings at concentrations greater than 0.03 and 0.1 mM, respective ly. These results suggested that L-tryptophan may be an allelochemical which affects the growth or germination of different plant species.