Effects of cooperation between associative azotobacteria and rhizobia on wheat seedling

Wheat seeds were inoculated respectively by different combinations between associative azotobacteria and rhizobia，and then planted in the pots filled with sterilized vermiculite for 28 days．The fresh weight，dry weight，total N ，the rate of F_v /F_m of wheat seedlings and root nitrogenase activity were measured．The results show that root nitrogenase activities of the seedlings inoculated by associative azotobacteria can be detected，some come up to 386．6(±3．5)nmol／g(fresh weight)．And the dry weight，total N，the rate of F_v /F_m of most seedlings inoculated together by associative 87．0-tobacteria and rhizobia are a little higher than those inoculated by only one kind of associative azotobactefia．Especially the nitrogen-fixing ability of combination between Klebsiella oxytoca and Sinorhizobium melilot Ⅱ is more notable and has application potential on the agricultural production．