AFFECTION OF FOUR FACTS ON NITROGEN-FIXING BACILLUS STRAINS
二株固氮芽孢杆菌的固氮特性研究

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.