【摘要】 用直接测量绿萍在自然生长状况下的固氮活性的方法,能维持绿萍原有的生态条件和生长状况,反映实际的固氮活性。绿萍的固氮活性时刻受环境条件影响而变化,随自然光强同步地变动。适宜光强和温度因萍种及季节不同有异。从固氮活性计算固氮量要作连续的测定。测定的反应时间以10分钟为宜,a值是3,K值为函数,应预测K值表以查对计算。一般在每天6、10、14、18时各测量一次,并以w=4（b+c）+8（a+b）/3×28×10^-3,计算得实际固氮量。更多还原

【Abstract】 A direct method for measuring N₂-fixing activity of Azolla without changing the ecological condition and growth of Azolla is described.The reaction time for the determination and the parameter "a", the conversion factor used to calculate the amount of N₂ fixed from that of C₂H₂ reduced, were found to be 10 min. and 3, respectively. The value "K", the ratio of （content ratio） to （peak ratio）, was not a constant, and should be determined by test.N₂-fixing activity of Azolla was often influenced by environmental factors. The optimum light intensity and growth temperature varied with the variety of Azolla and the season of growth. It must be emhasized that the calculation of the amount of N₂ fixed by Azolla should be based on successive determinations.Generally, it is preferrable to calculate the amount of N₂ fixed by Azolla by the following formula: where, a, b, c, and d are the N₂-fixing activity of Azolla determined at time 6, 10, 14 and 18 o’clock, respectively in a day.更多还原