Distúrbios fisiológicos associados à sensibilidade ao estresse hídrico em plantas de arroz

Abstract

Rice (Oryza sativa L.) is one of the most produced cereals in the world, together with maize and wheat, and when exposed to various adverse conditions, with water deficit, have its productivity compromised. Therefore, the present work aimed to characterize mechanisms indicating damage and oxidative protection that may be present in rice varieties São Francisco, BRS Sertaneja, BRS Primavera and BRS Pepita, when subjected to water deficit conditions. The experiment under greenhouse conditions is divided into three stages. The seeds of the varieties (BRS Sertaneja, BRS Primavera, BRS Pepita and São Francisco in the first phase and BRS Sertaneja and São Francisco varieties in the second and third phase) were disinfected with 5% sodium hypochlorite and sown in four liter pots. . A few days after seedling emergence, nutrient solution applications and biometric analyzes were started. After a certain time, the analysis of gas exchange, physiological and biochemical, as well as grain yield were made. The experiment was conducted in IHD in all stages, except for the first one, arranged in 2 x 2 factorial treatments, consisting of two water treatments (control treatment and water stress). The data of the analyzed variables were submitted to the F test at 0.05 probability and the means compared by the Tukey test at the same significance level. Different behaviors were obtained under optimal conditions due to the different genotypes showing that BRS Sertaneja and São Francisco are more efficient in the use of resources than the others under optimal conditions. In response to water stress, we obtained differences between varieties and between treatments in the same variety, since each one presents degree of sensitivity and response to external stimuli, so that the BRS Sertaneja variety was more resistant to drought and as a better option for use in semiarid region.