Antioxidant detoxification system of wheat and ryegrass plants subjected to various herbicides

Sistema de desintoxicação antioxidante de plantas de trigo e azevém submetidas a diversos herbicidas

ABSTRACT:

Herbicide promotes physiological and biochemical changes even in tolerant species. The objective of this study was to evaluate the interference of the herbicides clodinafop-propargyl and 2,4-D in the antioxidant system of wheat, and iodosulfuron-methyl in wheat and ryegrass. Two studies, divided into three experiments, were conducted in an entirely randomized design in a greenhouse and phytotron. The first study tested herbicides iodosulfuron-methyl, clodinafop-propargyl, 2,4-D, and a control without application in wheat. The second, divided into two experiments with wheat and ryegrass, tested iodosulfuron-methyl doses (0, 1.75, 3.5, and 7.0 g a.i. ha^-1). The variables analyzed were the concentrations of chlorophylls a, b, carotenoids, hydrogen peroxide (H₂O₂), lipid peroxidation (TBARS), electrolyte leakage, and antioxidant system activity. The herbicide treatments iodosulfuron-methyl, clodinafop-propargyl, and 2,4-D decreased the concentrations of chlorophylls and carotenoids in wheat plants. The herbicides promoted oxidative stress with increased H₂O₂ and TBARS concentrations. Increasing the dose of iodosulfuron-methyl provided a reduction in the activity of the enzymatic antioxidant system in wheat and ryegrass.

Key words:
Triticum aestivum L.; Lolium perenne L. var. multiflorum (Lam.); oxidative stress.