Tolerância de variedades de cana-de-açúcar (Saccharum officinarum L.) ao estresse salino

Abstract

The sugar cane became one of the primary cultures of the Brazilian economy. Currently we observe the growth of this culture to the Brazilian semiarid region, which has soils prone to salinization, being important in this environment the study of varieties resistant to salt stress. The objective of this study was to evaluate the tolerance of three varieties of sugar cane to the stress caused by salinity. The experiment was conducted in a greenhouse at the Universidade Federal Rural de Pernambuco (UFRPE), from June to August 2014. It was made a completely randomized design in a factorial 3 x 5 with four repetitions, and three varieties of sugar cane (RB92579, RB962962 and RB867515) and five levels of NaCl (0, 50, 100; 150; 200 mM NaCl). At the time were evaluated morphological parameters (height and diameter of the stem; leaf area, fresh weight, dry and water content of the plant and the root), and collected samples of the leaf blade to determine the enzymatic activity of catalase (CAT), ascorbate peroxidase (APX) and soluble protein (PS). Based on the results it was observed that salinity affected the morphological characteristics of the plant. At higher salt level, 200 mM, there was a decrease in all parameters. The protein content was higher for RB962962 and lower for RB92579 and RB867515 varieties. However, in RB867515 variety, it was noticed an increase in the peroxidase ascorbate (APX) and catalase (CAT), activities while in the varieties RB 92579 and RB962962 there was a reduction of the activity of these enzymes. These results indicate that the variety RB867515 presents a mechanism more efficient in plant protection against the action of reactive oxygen species.