Preeti Rathaur, Waseem Raja, P W Ramteke, S A John
Plant growth promoting rhizobacteria (PGPR) are beneficial bacteria that colonize plant roots and enhance plant growth by a wide variety of mechanisms. Six bacterial isolates, efficient in producing PGP compounds like IAA, Ammonia, HCN, Catalase and Siderophore were successfully isolated, characterized and designated as PG1, PGB3, PG5, PG7, PG9 and PG10. Prior to seeds grown in plastic pots, seeds were treated with PGPR isolates and seedlings were harvested after 21 days of inoculation. Results of first study showed seed inoculation significantly enhanced seed germination and seedling vigour of Withania somnifera. Also application of PGPR isolates significantly improves the percentage of seed germination and seedling vigour index under UV-B exposure. Subsequently to investigate the effect of PGPR isolates on the growth characteristics, a pot culture experiment was conducted. Most of isolates resulted in a significant increase of plant height, fresh and dry weight, and leaf area and leaf number. Results confirmed that bacterial inoculation had significant effect on stimulation of root and shoot growth. Our findings suggest that the use of PGPR isolates PG10, PG9 and PG7 as inoculants biofertilizers might be beneficial for growth of Withania somnifera.
