一种测定根瘤固氮酶活性的开放式气路系统及其应用

針對傳統的密閉式氣路法測定根瘤固氮酶活性（乙炔還原法，ＡＲＡ）所存在的缺陷，本試驗設計了一種簡單易行的開放式氣路測定根瘤固氮酶活性的方法，并對其在根瘤固氮生理學中的應用進行了研究。結果表明，應用本測定裝置所測得的根瘤固氮酶活性比用傳統的密閉式氣路法測得的固氮酶活性高40％以上。乙炔氣體可誘導健康根瘤固氮酶活性的抑制，但對受土壤干旱、去葉、環割等處理的根瘤固氮酶活性無此誘導抑制效應。用本測定裝置測定根瘤固氮酶活性所需乙炔氣的最適濃度為5％，比文獻報道的低25％-50％。土壤干旱、去葉、環割等處理顯著抑制根瘤固氮酶活性，抑制的原因與根瘤本身可溶性糖含量無關。
Noticed a decline in nitrogenase activity during acetylene reduction assay using the traditional closed gas exchange system, a simple and easily operating open flow gas exchange system was designed and its application in nitrogen fixation physiology was also investigated. The results showed that the nitrogenase activity (acetylene reduction activity, ARA) measured using the open flow gas exchange system was more than 40% higher than that measured using the traditional method. Acetylene induced decline in nitrogenase activity was found only in the healthy (unstressed) nodules, but not in the stress treated nodules. The optimal concentration of acetylene used in this system was 5%, which was 25%-50% lower than those reported. Soil drying, defoliation and stem girdling has a significant inhibitory effect on acetylene reduction activity of nodules, which had no relation to the total soluble sugar content in the nodules.