Co-inoculação de Bacillus aryabhattai e Trichoderma harzianum na atenuação da toxicidade do cádmio em Mimosa caesalpiniifolia e na modulação da atividade enzimática do solo

Abstract

Soil contamination by cadmium (Cd) poses a serious risk to the environment and public health, demanding efficient remediation strategies. This study evaluated the potential of co-inoculation with the bacterium Bacillus aryabhattai and the fungus Trichoderma harzianum in promoting growth and phytoremediation of Mimosa caesalpiniifolia (“sabiá”) in contaminated soil. The experiment was conducted in a greenhouse using a completely randomized design, in a factorial scheme, combining the presence or absence of Cd with four biological treatments: control, single inoculation of B. aryabhattai, T. harzianum, and co-inoculation (consortium), with 4 replications per treatment, statistically analyzed via ANOVA using the F-test (p ≤ 0,05). After 90 days, biometric parameters, soil enzymatic activity (β-glucosidase, arylsulfatase, and phosphatases), microbial biomass carbon (MBC), and Cd content in soil and plant were evaluated. The results demonstrated that the presence of Cd severely inhibited the growth of non-inoculated plants. However, co-inoculation mitigated metal toxicity, promoting an increase in shoot dry mass compared to the contaminated control. Furthermore, the inoculated treatments-maintained soil biological quality, increasing MBC and enzymatic activity. Regarding pollutant dynamics, co-inoculation reduced Cd concentration in roots and significantly increased the Translocation Factor, favoring metal transfer to the shoot. It is concluded that the synergistic association between M. caesalpiniifolia and the microbial consortium confirms the growth potentiation hypothesis, presenting itself as a promising strategy for the recovery of areas degraded by heavy metals.