IMPACT OF ALLELOPATHIC POTENTIAL OF MAIZE (ZEA MAYS L.) ON PHYSIOLOGY AND GROWTH OF SOYBEAN [GLYCINE MAX (L.) MERR.]

The aim of the present investigation was to determine the allelopathic effect of aqueous extract from either fresh or oven dried leaves and root of unstressed or water stressed maize plants on soybean growth and its effects on rhizosphere soil treated with maize plant extract. The extracts were applied for 10h to soybean [Glycine max (L.) Merr.] as seed soaking treatment prior to sowing. The application of extract prepared from fresh leaves of unstressed maize plants significantly increased micronutrients contents of soil. Higher concentration of Na+, K+, Ca2+ and Mg2+ contents were found in rhizosphere of soybean plants treated with fresh and oven dried leaf extracts of drought stressed maize plants. Both fresh and oven dried leaf extracts significantly increased the Fe+, Cu+, Cr3+, Zn2+ and Co+ content of soil. The extract prepared from fresh leaves of drought stressed maize plants significantly increased the accumulation of proline, sugar and endogenous abscisic acid content of soybean leaves. The protein content was decreased by these treatments. Significant increases were recorded in the activities of superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APOX), catalase (CAT) and endogenous abscisic acid in response to application of fresh as well as oven dried leaf extracts prepared from drought stressed maize plants. The leaf extracts were more effective than root extracts and oven drying further augmented its stimulatory effect on the accumulation of Na+ content and micronutrients eg. Co, Zn2+, Mn3+ and Cu+ etc. It can be inferred that aqueous extracts possess allelopathic effects which alter the physiology of soybean plants.