Plant growth promoting bacteria improve growth and phytostabilization potential of Zea mays under chromium and drought stress by altering photosynthetic and antioxidant responses

Drought in heavy metal polluted arid and semiarid regions severely inhibits the plant growth phytoremediation potential by affecting photosynthesis, antioxidant defense mechanism, other biochemical processes. In present study, we explored role of growth-promoting bacteria (PGPB) on Zea mays efficiency Chromium (Cr) contaminated soils under drought stress assessing tolerance, photosynthetic gas exchange activities, chlorophyll fluorescence, Cr accumulation. Two efficient resistant PGPB with to reduce Cr(VI) Cr(III) produce metabolites even Cr, drought, or Cr+drought conditions were isolated identified as Providencia sp. (TCR05) Proteus mirabilis (TCR20). pot experiments, inoculation TCR05 TCR20 increased growth, pigments, protein, phenolics, relative water content decreased lipid peroxidation, proline, superoxide dismutase activity conditions. Irrespective treatment, also improved increasing CO 2 assimilation rate, stomatal conductance vapor, transpiration maximum quantum PSII, actual electron transport photochemical quenching, reducing internal concentration non-photochemical quenching. Besides, translocation through immobilization root. These results denoted that strains could be a capable bio-inoculant for improving phytostabilization practices sites water-limited • Potential MST-PGPB isolated. enhanced tolerance Z. combined PSII performance stresses.