Env Exp Biol (2014) 12: 83–87

Evaluation of allelopathic effects of methanolic extracts from Salicornia herbacea seed and leaves on germination and seedling growth in vitro of two medicinal plants and two weeds

Abstract

In this study, methanolic extracts obtained from dried seeds and leaves of Salicornia herbacea, a medicinal plant, were evaluated at 2.5, 5 and 10% (v/v) in vitro for their potential allelopathic effects on the germination and seedling parameters of medicinal plants Hyssopus officinalis and Nigella sativa, and weeds Taraxacum officinale and Amaranthus retroflexus. Root length of T. officinale and A. retroflexus decreased significantly after exposure to 10% leaf extract, while all concentrations decreased the germination percentage of both weeds. Amaranthus retroflexus shoot length decreased significantly only after exposure to 10% leaf extract. In N. sativa, increasing concentration of leaf extracts increased shoot length and in H. officinalis maximum shoot length occurred at 5% concentration, but a further increase in concentration of leaf extracts had no negative impact on root length or seed germination. A very similar trend was observed for seed extracts. The negative effects on both weeds may be due to active compounds and/or allelochemicals in S. herbacea, whose seed and leaf extracts could be used as effective herbicides when applied at 5 or 10%, although the allelochemical(s) responsible for this allelopathic activity have yet to be identified.