Efficacy of citric acid chelate and Bacillus sp. in amelioration of cadmium and chromium toxicity in wheat.

Heavy metals contamination in agricultural soil is a major issue having drastic effects on plants and human health. To solve this issue, we have formulated and tested a new approach of fusion of inorganic (citric acid chelate) and organic (Bacillus sp.) amelioration methods for heavy metals. The Bacillus sp. was heavy metal tolerant and showed plant growth-promoting characteristics including phosphate solubilization, siderophore production, hydrogen cyanide production, indole acetic acid production, and 1-Aminocyclopropane-1-carboxylate deaminase production. The analysis of data showed that plants receiving the combined application of citric acid (CA) chelate and Bacillus sp. mitigated heavy metal toxicity. They augmented the biomass production and amount of photosynthetic pigments in plant cells. They suppressed the negative effects of Cadmium (Cd) and Chromium (Cr) on plants' metabolic systems. A considerable increase was also observed in the activity of enzymatic and non-enzymatic antioxidants which reduced the damaging effects of reactive oxygen species and maintained internal structures of cells. The decrease in the content of Cr and Cd in wheat grains by the treatment of CA chelate and Bacillus sp. was 51%, and 27% respectively. The bioaccumulation of metals was also reduced to 49% (Cr) and 57% (Cd). This approach can be tested and applied in field conditions for soils with heavy metals contamination.