Improving peanut growth and cadmium phytoextraction capacity by inoculating Bacillus megaterium and Trichoderma...

Arachis hypogaea L. (peanut) is an economic crop with abundant biomass and remarkable capacity for cadmium (Cd) uptake. In a two-year field experiment, the translocation and accumulation mechanisms of Cd in peanuts were investigated following inoculation of Bacillus megaterium (BM) and Trichoderma harzianum (TH). The results demonstrated that inoculating BM and TH enhanced both biomass and Cd concentration in peanut roots and shoots compared with those of the CK treatment. There was no statistically significant difference observed in kernel biomass between peanut plants inoculated with TH and the CK treatment. The inoculation of BM and TH increased the Cd concentration in the soluble fraction of peanut roots by 24.36% and 102.78%, thus promoting Cd translocation from roots to shoots. Additionally, inoculating BM and TH resulted in a 31.75% and 52.88% elevation in Cd concentration within the leaf cell walls, thereby facilitating the accumulation of Cd within the shoots. Simultaneously, inoculating BM and TH enhanced the concentration of highly bioavailable Cd forms in peanuts. The accumulation of Cd in shoots is the primary factor determining the phytoextraction capacity in peanut, and inoculation of TH resulted in a 16.35-54.54% increase in shoot biomass and an enhancement of 99.10-99.95% in shoot Cd concentration. Therefore, inoculating TH can enhance the phytoextraction capacity for Cd in peanuts, particularly the production of economically valuable components (kernels), without compromising production.