二株固氮芽孢杆菌的固氮特性研究

在无氮Ｈｉｎｏ培养基ＪＲ_１菌株的乙炔还原活性在氧浓度３％时最高，ＺＺ_１２菌株则随氧浓度上升而下降，但两菌株在空气条件下也能有效固氮；在有０．０１％酵母膏存在时，各氧气浓度菌株的乙炔还原值起伏不大。０．０２％铵盐存在时ＪＲ_１乙炔还原作用最强，但活性随硝酸盐浓度上升而一直下降；０．０２％硝酸盐时ＺＺ_１２菌株乙炔还原力最强，但其活性值随铵盐浓度递增而逐减。土壤中存在可利用糖类时ＪＲ_１和ＺＺ_１２

AFFECTION OF FOUR FACTS ON NITROGEN-FIXING BACILLUS STRAINS

The acetylene-reducing activity of JR1 strain was highest on 3 percent oxygen, the activity of ZZ12stain reduCed by increase of concentration of oxygen on the nitrogen-free medium, but two strains were able toreduce acetylene efficiently at air; while the acetylene-reducing values of two strains fluctuate within deviationson 0.01 per cent yeast extract Hino medium at different oxygen concentrates. The acetylene-reducing ability ofJR1 strain was best on 0.02 per cent ammonia, but reduced by the raise of concentrate of nitrate. In contrast theacetylene-reducing values of ZZ12 reduced with the rising of concentrate of ammonia and the highest value is on0.02 per cent nitrate. Only when utilizable carbohydrates (glucose) existed in soils, JR1 and ZZ12 strains wereable to reduce acetylene.