Mechanism of Soil Factors Affecting on Allelopathic Activity of Plant

在大多数研究中，许多潜在的化感物质都是从植物中分离出来的，并在水或沙子中进行了测试，但土壤中的化感作用尚未完全了解。本研究旨在获得影响土壤化感活性的土壤因子的基本信息，以便在可持续农业中更好地进行杂草管理，研究结果总结如下。研究结果表明：1.水提物和水浸提液对种子萌发和幼苗生长有抑制作用，抑制程度因植物种类不同而异，说明该植物含有水提物生长抑制物质(S)。与沙培和琼脂培养相比，从高山一枝黄花中分离得到的多叶脱氢菊酯水提物(DME)在土壤中的植物毒力显著降低。它们在土壤中的活性下降是由于它们在土壤中的吸附和降解所致。在种植杂叶松的土壤中发现了植物毒性活性，而在种植高山松的土壤中没有发现植物毒性活性。它们在土壤中的活性取决于它们在土壤水中的浓度，而土壤对它们的吸附和生物降解起主导作用。结果表明，植物体内和植物释放出的化学物质的植物毒性活性受土壤因素的影响，其活性取决于土壤水分中抑制物质的含量，而不是土壤中的总量。

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.