CHEMICAL INVESTIGATION ON SOME WEEDS OF RICE AND MUSTARD CROPS FOR JUSTIFICATION OF ALLELOPATHIC EFFECT

Abstract

The allelopathic effects of some weeds on germination and growth of rice and mustard seedlings with their chemical investigation were conducted in the laboratory.This study was performed on naturally occurring growth factors in. aqueous extracts of some common weeds viz. Aryl Leersia hexandra), Jaina (Fimbristylis miliacea), Sushnisak (Marsilea quadrifolia), Masurchana (Vicia hirsuta), Tita begun (Solanum nigrum) and Bankapi (Gnaphalium affine) with the attempt for chemical investigation on effective extracts. The boiled and unboiled extracts' of all the weed species prepared from whole plant were used for treating seeds of rice and mustard along with water as control. Boiled and unboiled extracts of all the weed species significantly reduced and delayed germination of rice and mustard seeds compared with control. The effect of unboiled extract ofJaina showed the lowest germination (82.7 %) in rice seed. But the unboiled extract of Aryl mostly inhibited the root and shoot length of rice seedlings. The effect of unboiled extract of Tita begun showed the lowest germination (50.6 %) in mustard seed and the unboiled extract of Tita begun inhibited the root and shoot length of mustard seedlings. The root and shoot length ofrice and mustard were reduced in presence of all the weed extract. The thin layer chromatography (TLC) examination of crude extract of Aryl (Leersia hexandra showed four separate compounds at hexane: ethyl acetate (10:1, v/v) and the crude extract of Tita begun (Solanum nigrum) also detected four separate compounds at hexane: ethyl acetate (10:1, v/v).