Alex Favaro Nascimento

Susceptibilidade de espécies de plantas com potencial de fitorremediação do herbicida sulfentrazone

Among the new technologies, phytoremediation is considered as an option for the decontamination of areas that thave undergone intense herbicide applications. This work aimed to select species with potential to the phytoremediation of soils contaminated with the herbicide sulfentrazone. The tested species were Calopogonium mucunoides, hybrid Sorghum (Sorghum bicolor x Sorghum sudanense), Crotalaria breviflora, Crotalaria juncea, Canavalia ensiformis, Dolichos lablab, Stizolobium deeringianum e Stizolobium aterrimum. The experiment was conducted in a greenhouse, using 6 dm3 vases filled with soil samples collected at a depth of 20 cm. The experimental design was the randomized blocks in a factorial scheme of 8 x 5, with four repetitions, which were composed by the eight plant species, and five doses of sulfentrazone (0, 200, 400, 800 and 1,600g ha-1). We evaluated the phytotoxicity of the herbicide, plant height and dry weight of shoots and roots. The species showing the least symptoms of phytotoxicity and the highest rates of height and fresh and dry biomass were C. juncea, C. ensiformis and D. lablab, which were selected as tolerant to the herbicide sulfentrazone and with potential for phytoremediation.

Risk of Soil Recontamination Due to Using Eleusine coracana and Panicum maximum Straw After Phytoremediation of Picloram

This study aimed to evaluate the herbicidal activity of picloram on the biomass of the remediation plants Eleusine coracana and Panicum maximum after cultivation in a soil contaminated with this herbicide. These species were grown in three soils, differentiated based on texture (clayish, middle, and sandy, with 460, 250, and 40 g kg–1 of the clay, respectively), previously contaminated with picloram (0, 80, and 160 g ha–1). After 90 days, the plants were harvested and an extract was produced by maceration of leaves and stems of these plants. It was applied to pots containing washed sand, comprising a bioassay in a growth chamber using soybean as a bioindicator for picloram. Soil and plant samples were analyzed by HPLC. The results showed the presence of picloram or metabolites with herbicidal activity in the shoots of E. coracana and P. maximum at phytotoxic levels with regard to soybean plants, indicating that they work only as phytoextractors and that the presence of straw on the soil surface can promote recontamination within the area. It is not recommended to cultivate species susceptible to picloram in areas where it was reported remediation by E. indica and P. maximum and still present residues of these species.