Primary Studies On Rhizobia Isolated From Root Nodules Of Acacia Cincinnata

Physiological and biochemical characteristics, adaptations to growth environment, inoculation in test tubes and potted seedlings of JJ01 to JJ12 rhizobial strains, and 16S rDNA PCR-RFLP and central strain of JJ01 to JJ15 rhizobial strains which isolated from root nodules of Acacia cincinnata were studied in this paper.According to tests of colony formation days on plate and generation time determination, all strains JJOl to JJ12 were primary clustered into groups: one is fast-growing rhizobium, the other is slow-growing rhizobium. The results showed that these strains varied in colony morphologies, growth rates, physiological and biochemical characteristics of these rhizobia. The optimum growth temperature of these strains was at 30℃. All strains grew with initial pH from 5.0 to 9.0 and were tolerant to salt on medium containing 0.5% NaC. Significant differences in antibiotic susceptibility were seen among these strains.In the test-tubes experiences, nitrogenase activities, mean nodule weight per seedling, mean nodule number per seedling and nodulation rate were different and have no significant correlation with original hosts.