Allelochemical stress produced by aqueous leachate of <Emphasis Type="Italic">Nicotiana plumbaginifolia</Emphasis> Viv.

The effects of aqueous leachate of Nicotiana plumbaginifolia Viv. on germination, seedling growth, amylase activity, sugar and starch contents of germinated seeds of maize (Zea mays L. cv. Uttam) were examined. Effects of leachate on photosynthetic pigments, protein content, activities of nitrate reductase and some antioxidants were also studied. Higher concentration of aqueous leachate of N. plumbaginifolia reduced the germination rate (GR). However, final germination percentage remained almost unaffected. Lower concentration of leachate stimulated the amylase activity and resulted in higher sugar content and GR. The increasing concentrations of leachate inhibited the conversion of starch into sugars. Allelochemicals decreased the amount of chlorophyll a, chlorophyll b, carotenoids, protein and nitrate reductase activity (NRA). The leachate of lower concentrations stimulated the activity of peroxidase but slight decrease was recorded in higher concentration. Superoxide dismutase and catalase exhibited concentration dependent increase except in seedlings treated with 100% concentration of leachate. Impairment of various metabolic activities due to leachate resulted in decreased root and shoot length.