内蒙古锡林郭勒草原不同固氮植物的固氮酶活性季节变化

 本文对内蒙古锡林郭勒典型草原栗钙土地带8种植物根瘤固氮酶活性的季节变化进行了测定。结果表明：1．不同种植物固氮酶活性表现了明显的季节性变化，夏季最高，平均值达到529.6n·mol C2H4／min·g，秋季较低，而春季只有夏季的10%左右。2．不同种植物，其根瘤固氮酶活性变化有不同的特点，杂花苜蓿是8种植物中固氮酶活性一直最高的，而小叶锦鸡儿与沙棘在8种植物中根瘤固氮酶活性一直较低，扁蓿豆，沙打旺前期较低，后期相对较高。3．同种植物在不同季节固氮酶活性表现了明显差别。

DETERMINATION OF THE SEASONAL CHANGES OF THE BIOLOGICAL NITROGEN-FIXATION ACTIVITY OF DIFFERENT PLANTS IN THE XILINGOULE GRASSLAND,INNER MONGOLIA

This paper deals with the determination of the seasonal changes in the nodule nitrogen-fixation activity of eight species of plants in the chestnut soil zone in the Xilingoule grassland of Inner Mongolia. The results show that mainly due to the changes in temperature and moisture in the soil, the nodule nitrogen-fixing activity of the different plants show obvious seasonal changes. The highest takes place in summer, the average value being up to 529.6nmol·C2H4/min·g, and the lowest takes place in autumn, the value in spring being only about 10 percent of that in summer.Different plants have different characters of nitrogen-fixing activity. Medicago facata has the highest nitrogen-fixing activity among the eight species of plants. Trigonella ruthenica and Astragalus absurgens have rather low activity at their early stage, becoming relatively high later. Caragana mocrophylla and Hippophae rhamnoides have the lowest nitrogen-fixing activity among the eight species.