Role of bacterial inoculation on growth of brinjal plant in cadmium contaminated soil

Heavy metals have toxic effects on plants as well as on human beings if they enter in their food chain in significant quantity. Among these heavy metals, cadmium is important as it is a contaminant of our soil and can adversely affect the biochemical and physiological processes of plants. Plant Growth Promoting Rhizobacteria play an effective role in crop production, growth promotion and in the improvement of soil health. In contaminated soil PGPR can be used to improve the plant growth and reducing the stress response on the plants. Cadmium is reported to affect the transport of the mineral nutrients, chlorophyll a and b content in the leaves and hence reduces the plant growth. Plant Growth Promoting Rhizobacteria can possibly revert the negative impact of cadmium contamination of plants. The present study was planned to observe and measure the effects of Cd on brinjal plant in the presence of PGPR. The roots of the plants were inoculated with three different bacterial strains i.e. 81, 82 and 83 with and without two different concentrations of Cd i.e. 20 mg per kg and 40 mg per kg added in the soil. At harvesting data regarding plant height, root length, plant fresh and dry mass, chlorophyll contents, transpiration, sub-stomatal CO2 conductance, stomatal conductance, water use efficiency and the cadmium content in the plant were recorded. The results showed that the cadmium contamination caused significant reduction in growth and yield parameters. However, inoculation with PGPR improved the plant growth and yield in cadmium contaminated soil. It was observed that inoculation with PGPR increased the yield of plants (13%) in cadmium stress (40 mg per kg) as compared to plants grown in cadmium contamination without inoculation (9%). Results showed that PGPR also reduced the uptake of cadmium in plants.