Can Trichoderma Spp. Contribute to the Bioremediation and Biostimulation of Plants in Soil Contaminated with Herbicides?

This work aimed to evaluate the potential of Trichoderma spp. in the bioremediation of herbicides and biostimulation of plants in herbicide-contaminated soils. In the first phase, the experiment followed a completely randomized design in a 4 x 3 x 4 factorial scheme with five replications, four strains of Trichoderma spp., three herbicides, and four herbicide doses. The mycelial growth speed index (MGSI) of Trichoderma spp. was obtained by growing it in a Petri dish with PDA associated with different doses of herbicides and evaluated every 24 h for 10 days. Results indicated the selection ofTrichoderma harzianumT1A to continue the experiment, as it showed an increase in MGSI with metsulfuron-methyl herbicide. The herbicides indaziflam and atrazine reduced the development of Trichoderma spp. The second phase evaluated cucumber cultivated at the scheme corresponding to three doses of the herbicide metsulfuron-methyl and with and without application ofT. harzianumT1A in six pots containing two plants per pot, totaling 12 plants/replications per treatment. The parameters chlorophyll a, chlorophyll b, chlorophyll total index, plant height, phytotoxicity, leaf area index, aerial part dry mass, root length, and root dry mass was assessed in cucumber plants. Herbicide application caused phytotoxicity in cucumber plants and reduced all development parameters evaluated in the first cultivation. The phytotoxic effect was still observed in the second cultivation, leading to reduced root and shoot dry mass using metsulfuron-methyl. The results showed thatT. harzianumT1A resulted in significant beneficial effects on cucumber development, increasing plant height by 36%, leaf area index by 71%, root length by 23%, shoot dry mass by 54%, and root dry mass by 21% in the first crop, across all herbicide doses used. In the second cultivation, no significant effect of Trichoderma application was observed. Therefore,T. harzianumT1A contributes to the biostimulation of plants in soil contaminated with metsulfuron-methyl and may contribute to bioremediation.