Effect of bacterial consortium on alfalfa (Medicago sativa L.) plant nutrient uptake and antioxidant enzymes at different levels of oily sludge

Abstract

Under stress environment of oily sludge, plants develop oxidative stress which effect nutrients uptake, activity of oxidative defence enzymes, cause ion imbalance and toxicity in plants. The present study was designed to develop a combination of bacterial consortium alone and with fertilizers that can help to improve alfalfa growth and plant defence system under stress environment of oily sludge contamination soils. For this study consortium was prepared from Bacillus cereus (Acc KR232400), Bacillus altitudinis (Acc KF859970), Comamonas (Acc KF859971) and Stenotrophomonas maltophilia (Acc KF859973) and was inoculated with fertilizer to oily sludge contaminated soils. A pot experiment was conducted using complete randomized design with three replicates. The plants were harvested at 21 d for estimation of protein, proline and antioxidant enzymes superoxide dismutase (SOD) and peroxidase (POD). The protein, SOD and POD contents in alfalfa were higher in oily sludge than soil without consortium, ammonium nitrate and diamamoiun phosphate. Consortium suppressed the oxidative stress of sludge treated plants. The inoculation of bacterial consortium enhanced the uptake of Ca, Mg, K and Na. The uptake of Ca, Mg, K, Fe, Cu and Zn increased significantly with consortium+fertilizer the availability of nutrients in soil with 30% and 60% of oily. Cd content was greater in root than leaves of alfalfa. The bacterial consortium helped to enhance plant growth and plant anti-oxidant enzymes system. The consortium with fertilizer is the best suitable combination for alfalfa that can improve the oxidative enzyme system of alfalfa and increases its growth and development.