ALLELOPATHIC EFFECTS OF RAIN LEACHATES AND ROOT EXUDATES OF CENCHRUS CILIARIS L. AND BOTHRIOCHLOA PERTUSA (L.) A. CAMUS

Studies on the allelopathy of Cenchrus ciliaris L., and Bothriochloa pertusa (L.) A. Camus showed that simulated and natural rain leachates from shoots and root exudates were inhibitory to various test species. The rain leachates and root exudates had differential toxicity against the Brassica campestris, Lactuca sativa, Setaria italica and Pennisetum americanum in various bioassays. Low concentration of inhibitors were either non inhibitory or were stimulatory to the germination and/or growth of tested species. Chromatography revealed the presence of chlorogenic, ferulic, caffeic, p-OH-benzoic, p-coumaric, vanillic, syringic and gentisic acids in natural rain leachates, all being proven allelopathic agents. It is concluded that the phytotoxicity was depending upon the concentration of rain leachates and root exudates, test species involved, and physiological parameters measured. Germination appeared to be a poor indicator of phytotoxicity than radicle growth.