ALLELOPATHIC EFFECT OF AQUEOUS EXTRACT OF HONEYWEED ON SEED GERMINATION AND SEEDLING GROWTH OF WHEAT

Abstract

The aim of this work was to investigate the allelopathic effect of honeyweed extract on seed germination and seedlings growth of wheat. Varying doses (5, 10 and 15%) of the aqueous extract of the honeyweed leaves were applied to surface sterilized wheat seeds at starting and 5 days after placing for germination on water soaked filter papers in the petri dish. The extracts of honeyweed inhibited seed germination and growth of wheat seedlings in dose and time dependent manage. Interestingly 5% aqueous extract displayed stimulatory effects on growth of the seedlings, however application of 10 and 15% extracts inhibited the growth seedlings, when applied at 5 days after the mechanism of inhibitory effects on seeds of honeyweed extracts on wheat. The dry matter of wheat seedlings were decreased with increasing the extract concentration. Thin layer chromatography of the methanol extract of honeyweed suggested the presence of 4-hydroxy benzoic acid including other allelopathic compounds in honeyweed inhibited germination and seedlings growth. Mineral composition was determined, they might have some stimulatory effect on seedlings growth. It was interesting that 5% extract inhibited germination and seedlings growth, when it was applied during the time of seed germination, but stimulated seedling growth, when it was applied at 5 days after germination. To find out molecular mechanism behind it, further research is to be done.