Combined application of biochar and PGPR alleviates Cd stress in wheat by improving antioxidant defense mechanism and crop physiology

Soil heavy metals toxicity is an emerging threat for ecosystem and environment; therefore a greenhouse pot experiment was conducted to investigate the impact of corn stalk (CSBC) and farmyard manure biochar (FYMBC) coupled with the seed inoculation of <i>Bacillus cereus</i> (PGPR1) and <i>Pseudomonas frederiksbergensis</i> (PGPR2) strains under Cd stress on wheat production, antioxidants, osmoprotectants and soil biochemical characteristics. Overall, results of the study revealed that Cd pollution significantly (<i>p</i> < 0.05) reduced the plant growth by accumulating in plant tissues. However, the combined application of FYMBC+PGPR2 notably improved plant physiology and yield attributes. Moreover, wheat chlorophyll a (15.27%), b (16.39), total chlorophyll (15.96), photosynthetic rate (22.29), stomatal conductance (13.52) and transpiration rate (12.21) significantly increased under FYMBC+PGPR2 treatment. Similarly, a significant improvement was also observed in plant osmoprotectants and antioxidants activity, whilst Cd uptake in roots and shoots decreased up to 39.37 and 55.32% under respectively FYMBC+PGPR2 amendment. Additionally, soil nutrients including total N (565.61), available P (42.15) and K (19.78) along with PLFA (49.78) and bacterial CUE (63%) also showed efficiency under the integrated application of FYMBC+PGPR2. Inclusively, these findings provide a sustainable solution for the bioremediation of Cd in agricultural soil by improving soil and plant health.