RESPOSTAS MORFOANATÔMICAS E FISIOLÓGICAS DE DUAS ESPÉCIES ARBÓREAS SOB DERIVA SIMULADA DO HERBICIDA GLIFOSATO

Abstract

Glyphosate is a widely used herbicide worldwide, but its use can have negative impacts on non target species in native vegetation areas. In this study, the aim was to evaluate the effect of glyphosate on two native tree species, one with a wide distribution in Brazil and another endemic to the Amazon. Two experiments were conducted, the first simulating glyphosate drift on the Sapindus saponaria species, with sub-doses of 0, 24, 48, 96, and 192 g a.i. ha -1 , and the second using the Caryocar villosum species, with treatments of 0, 48, 96, 144, and 288 g a.i. ha -1 . The species responded differently to glyphosate exposure. S. saponaria showed higher sensitivity, exhibiting visual and anatomical damage, starch and phenolic compound accumulation, as well as physiological alterations in gas exchange parameters and photochemical steps as the sub-doses increased. On the other hand, C. villosum demonstrated tolerance characteristics to the tested sub-doses, as no significant changes were observed in morphology, anatomy, pigment content, and chlorophyll a fluorescence. However, there were changes in chlorophyll autofluorescence parameters, photosynthetic rate (A), and transpiration rate (E). These differences can be attributed to the presence of leaf barriers, such as trichomes, which possibly reduced herbicide absorption. These results highlight the importance of considering the differential responses of native species to glyphosate. While some species may be more sensitive and suffer significant damage, others may exhibit tolerance characteristics that protect them from the toxic effects of the herbicide. Understanding these responses is essential for the development of more efficient and sustainable management strategies in native vegetation areas, aiming to minimize the negative impacts of glyphosate on biodiversity.