气候因子对三种豆科树种固氮的影响

Effect of Climatic Factors on Nitrogen Fixation in Three Leguminous Trees

研究了气候因子对台湾相思(Acaciaconfusa)、大叶相思(A.auriculaeformis)和南岭黄檀(Dalbergiabalansae)根瘤固氮酶和吸氢酶活性的影响。3种树木根瘤均具有吸氢酶活性,外源H2可提高固氮酶活性,表明吸氢酶有助于固氮效率的提高。3树种根瘤的固氮活性有明显季节变化,夏秋活性较高,早春及冬季活性较低。离体根瘤固氮和吸H2活性表达的最适温度为25-30℃。光照强度及土壤湿度均显著影响根瘤固氮和吸H2活性。

Effect of climatic factors on nitrogenase and hydrogenase activities in nodules of Acacia confusa, A. auriculaeformis and Dalbergia balansae were investigated. Hydrogen uptake activity was found in the nodules of all the three leguminous trees. In the presence of exogenous hydrogen, nitrogenase activity in nodules increased markedly, indicating that hydrogenase played an important role in increasing the efficiency of nitrogen-fixation in symbiotic system. Seasonal changes were obvious in nodulation and nitrogen fixation of leguminous species grown in Xiamen area. Results showed that more nodules produced and higher C2H2-reducing activity were observed in summer and autumn than in early spring and winter. The optimun temperature for both nitrogenase and hydrogenase activities in nodules was 25-30℃. Minor soil water deficit did not affect the C2H2-reducing activities, but serious soil drought markedly reduced the activities of nitrogen-fixation and hydrogen uptake. Shading reduced both nitrogenase and hydrogenase activities in nodules.