Evaluation of effects of bio-fertilizers on some physiological and biochemical traits in soybean under water deficit condition

To evaluate the effect of bio-fertilizers on physiological traits in soybean under water deficit condition، a greenhouse experiment was conducted in 2011، at faculty of Agriculture، Tarbiat Modares University، using a factorial design based on RCBD with three replications. The experimental treatments were different irrigation regimes including non-stress (40% water depletion)، moderate stress 60% water depletion) and severe stress (80% water depletion) and four methods for application of mixed of Azotobacter and Azosperilium on plant or seed. Results showed that the highest yield and yield components were observed in non-stress and spraying of bacteria on leaf + seed inoculation conditions. The highest catalase enzyme activity was observed in moderate stress and seed inoculation + spraying of bacteria on leaf condition. In addition، the highest proline content was showed in severe stress and nonbacterial inoculation and was three times more than the minimum treatment. The results generally indicated that using bio-fertilizer in moderate stress can reduce the destructive effects of stress and decrease of yield، but severe stress led to increase of cost of production and could not effect on increasing of yield significantly.