Análises morfo-fisiológicas de plantas de acrocomia aculeata sob aplicação de glyphosate, visando dar suporte a sistemas de produção agroenergéticos

Abstract

Oilseed crops are the most studied in the industrial agronomic environment, due to their renewable energy power, in the production of biofuels. Acrocomia aculeata, despite not yet being considered a crop, due to not having been domesticated, has shown in several studies to be promising for the bioenergy market, producing between 5000 and 6000 kg of oil per hectare year, surpassing large crops. The objective of this research was to analyze the effects of the herbicide glyphosate on the physiological, biochemical characteristics of the enzymatic antioxidant system of A. aculeata, bringing biometric and visual behavioral results, for the control of weeds, which can harm its development when young. The experiment was installed under field conditions, at the experimental station on the campus of the Federal University of Tocantins - UFT, Palmas-TO, in April 2022, when the plant had already germinated for 8 months. Installed in 35 liter polyvinyl chloride (PVC) vases. The experimental design was randomized blocks, with 5 treatments, corresponding to 5 servings of glyphosate Roundup Original ®DI (360 g.e.a L-1): 0 g.e.a ha-1 (T0); 90 g.e.a ha-1 (T1); 180 g.e.a ha-1 (T2); 360 g.e.a ha-1 (T3) and 720 g.e.a ha-1 (T4) of concentration, in 4 repetitions, using 3 plants per repetition. Physiological and biochemical analyzes were carried out every 7 days after application (7, 14, 21, 28 and 35 DAA), using IRGA, evaluating the variables: intracellular carbon, net CO2 assimilation rate, stomatal conductance, transpiration and temperature of the sheet; and morphological - fresh and dry mass of shoots, fresh and dry mass of roots and height increment. Only T4 showed a visual phytotoxic effect due to the herbicide. For the increase in height, there was a 16.4% increase in the T3 treatment with a dose of 360 g.e.a ha-1. Doses above 360 g.e.a ha-1 significantly reduced the biomass and root volume of macaúba plants. The dose of 720 g.e.a ha-1 reduced the growth of macaw palm plants by 50% and affected all physiological variables. Higher concentrations of shikimic acid were observed in treatments T3 and T4.