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. ABSTRACT species clodinafoppropargyl clodinafop propargyl 2,4D 24D D 2,4 2 4 iodosulfuronmethyl iodosulfuron methyl ryegrass studies phytotron iodosulfuronmethyl, methyl, clodinafoppropargyl, propargyl, 2,4D, D, second 0, 0 (0 175 1 75 1.75 35 3 5 3.5 70 7 7. ai i a.i ha1. ha1 ha . ha-1) b H2O2, HO , H O (H2O2) TBARS, (TBARS) leakage plants H2O 4D 24 2, ( 17 1.7 3. ha-1 (H2O2 (TBARS 1. ha- (H2O
RESUMO: A aplicação de herbicidas promove alterações fisiológicas e bioquímicas mesmo nas espécies tolerantes. O objetivo do estudo foi avaliar a interferência dos herbicidas clodinafop-propargyl e 2,4-D no sistema antioxidante do trigo, e iodosulfuron-methyl em trigo e azevém. Dois estudos, divididos em três experimentos, foram conduzidos em delineamento inteiramente casualizado em casa de vegetação e fitotron. O primeiro estudo testou os herbicidas iodosulfuron-methyl, clodinafop-propargyl, 2,4-D, e testemunha sem aplicação em trigo. O segundo, dividido em dois experimentos com trigo e azevém, testou doses de iodosulfuron-methyl doses (0, 1,75, 3,5, and 7,0 g i.a. ha-1). As variáveis analisadas foram as concentrações de clorofilas a, b, carotenoides, peróxido de hidrogênio (H2O2), peroxidação lipídica (TBARS), extravazamento de eletrólitos e atividade do sistema antioxidante. O uso dos herbicidas iodosulfuron-methyl, clodinafop-propagyl e 2,4-D diminuíram o teor de clorofilas e carotenoides nas plantas de trigo. Os herbicidas promovem estresse oxidativo com aumento no teor de H2O2, TBARS e extravasamento de eletrólitos. O aumento da dose do iodosulfuron-methyl proporciona redução da atividade do sistema antioxidante enzimático no trigo e azevém. RESUMO tolerantes clodinafoppropargyl clodinafop propargyl 2,4D 24D D 2,4 2 4 iodosulfuronmethyl iodosulfuron methyl azevém estudos fitotron iodosulfuronmethyl, methyl, clodinafoppropargyl, propargyl, 2,4D, D, segundo 0, 0 (0 175 1 75 1,75 35 3 5 3,5 70 7 7, ia i i.a ha1. ha1 ha . ha-1) b H2O2 HO , H (H2O2) TBARS, (TBARS) clodinafoppropagyl propagyl 4D 24 2, ( 17 1,7 3, ha-1 H2O (H2O2 (TBARS 1, ha- (H2O