Physiological and morphoanatomic responses of bowdichia virgilioides kunth. (fabaceae) to glyphosate

Abstract

The expansion of agribusiness in Brazil is partly due to the expansion of arable areas in the Cerrado biome, which, consequently, leads to an increase in the use of herbicides, including glyphosate. Therefore, the objective of this study was to evaluate the physiological and morphoanatomic responses of Bowdichia virgilioides Kunth. (Fabaceae), when exposed to the herbicide glyphosate, under controlled greenhouse conditions. In addition, the study proposed to identify possible response patterns of the studied species and provide subsidies for the study of the species in areas affected by the drift of the herbicide. The experimental design was in randomized blocks, with seven doses of the herbicide: 25, 50, 100, 200, 400, 800, and 1200 g i.a ha-1 besides the control (0), with four repetitions each. Gas exchange, chlorophyll a fluorescence emission, chloroplast pigment content, membrane permeability, and visual and anatomical features were analyzed. The results showed that glyphosate is phytotoxic to B. virgilioides because, even at low doses, this herbicide was able to affect all parameters analyzed. There was also confirmation of the presence of phenolic compounds, mainly in the palisade parenchyma. The metabolic alterations presented demonstrated the sensitivity of B. virgilioides to glyphosate. Thus, the observed responses can serve as a tool for diagnosing the effects of glyphosate exposure on this species, present in native areas affected by the drift of this herbicide. Its indiscriminate use poses a risk to Cerrado biodiversity.