摘要
羊奶果根瘤多年生,初发生时呈2—3分又状,后经多次分叉生长,形成珊瑚状的根瘤簇,外形球状或扁球状,直径可达数厘米。根瘤固氮活性较高,全年平均固氮活性8.86微摩乙烯/克鲜瘤/小时。固氮活性秋夏较高,冬春较低。根瘤离体后固氮能力持续时间较长,可达9小时。固氮作用最适温度为30℃,低温使固氮活性显著下降,短时间高温(37℃)能提高根瘤固氮活性,但持续高温会抑制固氮活性。 羊奶果根瘤具有氢酶,表现出较高吸氢活性(9.52微摩氢/克鲜瘤/小时),且持续时间较长。外源氢能明显提高根瘤固氮活性,提高幅度达60％左右。 羊奶果各器官硝酸还原酶活力为根>根瘤>叶片>枝条,叶片NR活力呈季节性变化,秋夏较高,冬春较低。根瘤NR活力变化较大,且与根瘤固氮活性变化的趋势基本一致。
Elaeagnus conferfa is a tropical fruit tree, which is one of Actinorhizal plants, bearing perennial, multiple branching, coralloid no-dule clusters. The nitrogenase activity of nodule clusters of the plant was higher than that of the eight species of non-leguminous nodulated plants determined in Xiamen. The seasonal variation of nodules nitrogenase activity was found higher in autumn and summer than in spring find winter. The optimum temperature for nitrogen fixation of nodules ranged 25-30℃. The nitrogenase activity reduced below 25℃ or Over 30℃.
The uptake hydrogenase activity of nodules was 9.52μmol H2 /g · FW/h, When adding 5% H2 to reaction system, nitrogenase activity in nodules increased markedly.
The in vivo nitrate reductase (NR) activity in E, conferta young trees was determined. The NR activity in different organs was in the order roots>nodules>leaves>shoots.NR activity in leaves was higher in autumn and summer than in spring and winter.
关键词
羊奶果
结瘤
固氮
氢酶活性
Elaeagnus conferta, Nitrogenase activity, Hydrogenase activity, NR activity
