Water Stress Amelioration and Plant Growth Promotion in Capsicum Plants by Osmotic Stress Tolerant Bacteria

The present study was initiated with testing of fifteen previously isolated indigenous plant growth promoting rhizobacteria for drought tolerance. Among all, two best isolates Pseudomonas aeruginosa (JHA6) and Bacillus amyloliquefaciens (ROH14) were selected for in-vivo studies. A total of ten treatments comprising Plant growth promoting rhizobacteria (PGPR) (JHA6 and ROH14) inoculated plants held at 80%, 60% and 40% field capacity (FC) soil moisture level was laid down in Completely Randomized Design with three replications. Un-inoculated plants held at various stress levels and non-stressed conditions (100% FC) served as control. In general, both the bacteria could promote Capsicum growth in terms of increase in root and shoot biomass, height of plants, chlorophyll content as well as increase in nutrient content and uptake. Besides, the bacterial inoculated Capsicum plants could withstand water stress more efficiently as indicated by increases in leaf area, total soluble proteins and relative water content of treated water stressed plants in comparison to untreated stressed ones. Enhanced antioxidant responses were evident as elevated activities of enzymes such as superoxide dismutase, catalase and peroxidase was recorded. Therefore, the ability of Capsicum plants to tolerate water stress is enhanced by application of the isolated bacteria which also function as plant growth promoting rhizobacteria.