用^15N示踪标记法测定人工诱发黄瓜根瘤固氮酶活性

报道了用＾１５Ｎ示踪标记法对人工诱发黄大氮酶活性的测定结果，将长有人工诱发根瘤的黄瓜根系暴露在＾１５Ｎ２的气体中，部分根系浸在无氮培养液内，标记４８ｈ后，质谱分析测定结瘤黄瓜根＾１５Ｎ的丰度为０．４３１原子％＾１５Ｎ，样品为０３６９原子％＾１５Ｎ，对＾１５Ｎ示踪标记结果进行了统计学ｔ检验，ｔ＝３．１５〉６０．０１＝２．８１９，表明黄奶系根瘤内的细菌固氮作用所的氮与相比达９９．９％极显著性水平，同时

Determination of Nitrogenase Activity of Induced Cucumber Nodules by 15 N Trace Method

Reports the determination results of nitrogenase activity of induced cucumber root nudules by 15 N trace method. The root systems bearing induced nodules of cucumber were exposed to a gas mixture containing 15 N 2 for 48 h and partial root systems soaked in free nitrgen culture solution simultaneusly. After exposure the 15 N content in the modulated root systems of cucumber is 0 431 Atom % 15 N by mass spectrometric analysis, whereas in the contrast samples without exposure to 15 N is 0.369 Atom % 15 N. The statiatical t test for the results of 15 N trace experiments is: t =3.15> t 0.01 =2.819, It has been demonstrated that the nitrogenase activity in cucumber nudules is at a remarkable level of 99.9%. The nitrogenase activity in detached nodules of cucumber was also determined by conventional acetylene reduction method. In both methods clear evidences of nitrogenase activity were obtained for the induced nodules of cucumber.