Allelopathic effects of medicinal plant species on seed germination and seedling growth of wheat varieties

摘要

Allelopathic effect of three medicinal plant species viz. Costus speciosus, Tinospora cordifolia and Coleus forskohli was examined on seed germination and seedling growth of four popular varieties (Pusa gold, HD2733, VL-914, RSP 561) of wheat (Triticum aestivum L). The aqueous leaf extracts reduced the seed germination and seedling growth of wheat. On the basis of value of per cent reduction in seed germination and germination relative index (GRI), the inhibitory effect of different leaf extracts was maximum in susceptible varieties (VL-914& RSP 561) followed by tolerant varieties (Pusa gold & HD2733). The root and shoot length, root and shoot dry weight declined with the increase in the concentration of the extracts of all the three medicinal species.Leaf extract of these medicinal species also showed inhibitory effect on sugar and protein levels but stimulatory effect on total amino acid contents of wheat seedlings. The results indicated that the allelopathic effect of leaf extracts of Coleus forskohlii was maximum in terms of all studied physiological and biochemical parameters.