The response of Azorhizobium caulinodans to reactive oxygen species such as hydrogen peroxide (H₂O₂) plays an important role in nodulation and nitrogen fixation. It has been found that pretreatment of A.caulinodans with a selective oxidant viz., H₂O₂ (200μM) has enhanced the osmotic, thermal, and desiccation tolerence. The survivability in different carrier materials was found to be enhanced by H₂O₂ pretreatment as compared to untreated controls. A pot culture study was conducted to compare the effi ciency of H₂O₂ pretreated cells for nodulation, plant dry wt and ARA activity in Sesbania rostrata, followed by the Sesbania incorporation as green manure for rice grown under pot culture condition. The crop was studied for certain plant growth and yield components, such as plant ht, plant dry wt, no of panicles, total “N” uptake. The results of our present study have showed that the plant inoculated with H₂O₂ pre-treated cells of A. caulinodans positively augmented an increase in the growth and yield in both Sesbania rostrata as well for rice grown under flooded conditions in the pot culture experiment.

Key words: Azorhizobium caulinodans, hydrogen peroxide, carrier material, rurvival, rice

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