Effects of inoculation with plant growth promoting rhizobacteria on photosynthesis, antioxidant status and yield of runner bean

Abstract

Plant Growth Promoting Rhizobacteria (PGPR) play an important role in agricultural systems, especially as biofertilizer. Therefore, two rhizobacterial strains positive for phosphorous solubilization and siderophore production (S4) and for indoleacetic acid production (S7) were used to determine the effects of seed inoculation on growth of runner bean plants. The tested strains, alone or in combination, increased photosynthesis, transpiration, water use efficiency and leaves chlorophyll content. Also an increase of superoxide dismutase and peroxidase activity was recorded during periods with intense photosynthesis. S7 inoculation significantly increase the grains yield with 41.40 %. The PGPR strains improve the nutritive value of the harvested grains by enhancing the soluble protein content up to 16.24 % and total reducing carbohydrates content up to 49.28%. The inoculation response was comparatively higher at the early growth stages. Our study suggests that the two PGPR strains may be used as biofertilizer for vegetable production in sustainable and ecological agricultural systems.