几种豆科固氮树种吸氢能力研究

Hydrogenase Activity in Some Species of Leguminous Trees

测定15种具结瘤固氮能力的豆科植物根瘤的固氮酶和吸氢酶活性，测得其中灰金合欢、银合欢K8和毛萼田菁（属一年生草本植物）等根瘤具有较高吸氢酶和固氮酶活性。在银合欢根瘤固氮系统中注入外源H2，可提高固氮酶活性。这表明吸氢酶有助于提高固氮效率。检测13株从9种豆科植物分离得到的根瘤菌在自生条件下的吸氢酶活性，有12株根瘤可测出吸氢酶活性，其中84L和53菌株表达较高活性。84L和53菌株自生培养物的吸收分子氢系统可以在异养的固体或液体培养基中表达，吸氢酶活性表达的最适温度可能为30℃。

Nitrogenase and hydrogenase activities were 'etermined in nodules of 15 speciesof leguminous plants. Of the plants Acacia glauca, Leucaena leucocephala and SesbaniaTostTata (annual herb)showed higher hydrogen uptake activity. In the presence of exogenous hydrogen, nitrogenase activity in nodules of L. Leucocephala increased markedly,suggesting that hydrogen played an important role in increasing the efficiency of nitrogenfixation in symbiotic system. Thirteen free -living strains of Rhizobium iso1ated from thenodules of nine species of leguminous plants were determined for the hydrogen uptakeactivity. Twelve strains showed hydrogen uptake activity, of which strains 84 L and 53showed higher hydrogen uptake activity- The expression of hydrogenase in free -1ivingcultures of strains 84 L and 53 occurred under heterotrophic growth conditions in bothsolid and liquid mediums, and the favorable temperature for the expression ofhydrogenase was about 30℃ for both strains.