根际优势菌耐药菌株的获得及其^（15）N标记

OBTAINING STREPTOMYCIN RESISTANCE STRAIN FROM PREDOMINANT RHIZOSPHERE BACTERIA AND ITS ￣(15)N LABEL

对两株具有反硝化活性的根际优势细菌进行了耐药性和￣（１５）Ｎ标记；研究了该双标记菌株在土壤中的动态及其活性。结果表明，所用双标记方法是可行的，应用标记菌株可以追踪其在土壤中的消长。结果还表明，标记￣（１５）Ｎ菌株的￣（１５）Ｎ丰度与供试培养基中氮源的￣（１５）Ｎ丰度相近；标记菌株的反硝化活性与出发菌株的相同。

Two strains of predominant rhizosphere bacteria having denitrifying activity were la-belled with streptomycin and with ￣(15)N-(NH_4)_2SO_4;the dynamics and activities of these double la-belled strains in soils were investigated.The results obtained showed that the double labellingmethod used in this paper was feasible,and that the labelled strains can be used to trace thegrowth and decline of them in soils.The results also showed that the ￣(15)N abun-abundance of ￣(15)N-labelled strain was similar to those of the nitrogen resources in the medium tested,and that thedenitrifying activities of double labelled strain and its original atrain were the same.