Physiological activity of sugarcane after the application of pre-emergence herbicides

Abstract

The objective of this study was to evaluate the physiological characteristics of sugarcane after application of pre-emergence herbicides. For this, an experiment was conducted in a 2x5 factorial scheme, where the first factor consisted of cultivates RB 867515 and SP 81-3250, and factor B of the pre-emergence application of tebuthiuron, diuron, ametryn, a formulated mixture diuron + hexazinone and a control without herbicides. The experimental design was completely randomized, with four replications. The internal concentration of carbon (Ci), internal and external carbon (Ci/Ca) and SPAD index of cultivars of sugarcane ratio were not affected by the application of pre-emergence herbicides. However, stomatal conductance (gs), respiratory rate (E) and the photosynthetic rate (A) were reduced when treated with tebuthiuron. The A and efficiency of water use (U.S.) cultivar RB 867515 was negatively altered by the application of ametryn. It is concluded that a difference in sensitivity of the genotypes of sugar cane herbicide, and the SP 81-3250 was more tolerant. The application of tebuthiuron and ametryn reduces the A of RB 867515.