三裂叶豚草(Ambrosia trifida)对大豆根系生长及其结瘤的影响

沈阳效区实地考察中观察到，邻近三裂叶豚草生长的大豆的根瘤形成受到了抑制。土箱实验中得到和野外调查一致的结果，但大豆根系发育和分布不受影响。施用三裂叶豚草水浸液的实验表明，是三裂叶豚草水浸液，即：水浸液中的化学物质，抑制了根瘤菌的活动从而影响大豆根瘤的形成。文章给出了调查和实验的结果，并进行了分析。

EFECT OF Ambrosia trifida ON ROOT GROWTH AND NODULATION OF SOYBEAN

A unique phenomenon was observed when soybean grew adjacent with Ambrosia trifida, that the nodulation of soybean was remarkably inhibited.In the designed experiment in which soybean grew with or without A.trifida and the soil was spiked with Bradyrhizobium japonicum, the same phenomenon appeared.Soybean has less amount and smaller sizes of nodes when growing with A.trifida, compared with that growing without A.trifida .The same result was obtained in experiment by spraying aqueous extract of stem and root of A.trifida to the sand medium where soybean grew in.The results indicate that the activity of B.Japonicum was inhibited by the materials in the aqueous extract. The chemicals in the aqueous extract are mainly terpenoid,organic acids and polyyne.Rich polyyne in A.trifida are postulated to be the main cause of the inhibition of nodulation.However,the results of the field observation and experiment show that A.trifida did not have obvious influence on the root growth of soybean.