Abstract: Nitrogenase and hydrogenase activities were determined and the relation-ship between them was investigated in the nodules of Dalbergia balansae under different environmental conditions,Hydrogen uptake activity was found in the nodules of D. balansae. In the presence of exogenous hydrogen,nitrogenase activity in nodules increased markedly,suggesting that hydrogenase played an important role in increasing the efficiency of nitrogen-fixation in symbiotic system. Low level of nitrate did not influence the nitrogenase and hydrogenase activities in the nodules,however,ammonium showed a negative effect on the expression of both enzyme activities. The optimum temperature for both nitrogenase and hydrogenase activities was about 25℃. Minor soil water deficit did not affect the acetylene-reducing activity,but serious soil drought markedly reduced the activities of nitrogen-fixation and hydrogen uptake. Shading reduced both nitrogenase and hydrogenase activities of nodules.

Key words: Dalbergia balansae, Nitrogenase, Hydrogenase

摘要： 测定不同环境条件下南岭黄檀根瘤固氮酶和吸氢酶活性。结果表明,南岭黄檀根瘤具有吸氢酶活性,外源H₂可提高固氮酶活性(25%),表明吸氢酶有助于提高固氮效率。低浓度的硝酸盐(20 mg·1^-1)不影响根瘤固氮酶和吸氢酶活性,但浓度达40 mg·1^-1)时有抑制作用,而铵盐在上述浓度下均表现抑制作用。离体根瘤固氮酶和吸氢酶活性表达的最适温度为25℃,过高或过低均有抑制作用。土壤含水量及光照强度均明显影响其固氮酶和吸氢酶活性。

关键词: 南岭黄檀, 固氮酶, 吸氢酶