Mechanism of Soil Factors Affecting on Allelopathic Activity of Plant

点击翻译按钮获取中文摘要

Many potentially allelopathic chemicals have been isolated from plants and assayed in water or sand in most studies, but allelopathic activity in soil has been not yet fully understood. The study was conducted to obtain the basic information on the soil factors affecting on allelopahic activity in soil for better weed management in sustainable agriculture, The results obtained in the study are summarized as follows.1. Water extracts and water leachates from Tithonia diversifolia plant inhibited seed germination and seedling growth and the degree of inhibition varied depending on plant species, demonstrating that this plant contains water extractable growth inhibitory substance(s).2. The phytotoxic activities of water extract from T.diversifolia and dehydromatricaria ester(DME), which had been considered as allelopathic chemical, isolated from Solidago altissima was remarkably decreased in soil, when comparred with those in sand and agar culture. The decrease in their activities in soil were due to their adsorption and degradation in soil. Phytotoxic activity was found in the soil previously planted with T.diversifolia but not in that with S.altissima. Their activities in soil depended on the concentration of them in the soil water which was dominated by soil adsorption and biodegradation in soil.3. The results suggest that the phytotoxic activity of chemicals contained in and released from plant is affected by soil factors, and that the phytotoxic activity depends on the amount of inhibitory substances contained in soil water but not on the total amount in soil.