Abstract

This study is based on the phytotoxic effect  of aqueous extracts of the weed  Cyanodondactylon (L.) Pers. and  Cyperus rotundus L. on seed germination, early seedling performance and pigment profile of Vigna radiata (L.) R. Wilczek.. The different concentrations (5g/l, 10g/l, 20g/l, 30g/l, and 40g/l) of aqueous extracts of C.dactylon and C.rotundus were employed to investigate their influence on the seedling physiology of green gram. The aqueous whole plant extracts ( from 10g/l to 40g/l concentrations ) of C.dactylon and C.rotundus exhibited an inhibitory effect on germination percentage, root length, shoot length, vigour index, pigments, proteins, carbohydrates, and amino acid contents of V. radidata over control.  The extracts of both weeds caused a stimulatory effect on green gram seedlings at 5g/l concentrations  and the intensity of inhibition increased when the extract concentrations were increased. The photosynthetic pigments such as chl-a, chl-b and total chlorophyll exhibited significant reduction while carotenoid content was increased in all treatments compared to control.  The aqueous extracts of C.rotundus showed more inhibition on green gram seedlings than C.dactylon.   All treatments significantly reduced the Physiological activities of the pulse crop. All treatments significantly reduced the Physiological activities of the pulse crop, and the results suggest that the aqueous extractives from the bioparts of C.dactylon and C.rotundus were phytotoxic to the green gram seedlings.