CRESCIMENTO, SÍNTESE DE SOLUTOS ORGÂNICOS E EQUILÍBRIO IÔNICO DE PLÂNTULAS DE PINHÃO-MANSO SOB ESTRESSE SALINO

Abstract

This study evaluated the effect of different salt concentrations on growth, synthesis of organic solutes and ionic balance (Na+, Cl- and K+) of Jatropha curcas L. for 28 days. Seven treatments were established: 0, 15, 30, 45, 60, 75 and 90 mol m-3 NaCl in a completely randomized design with five replicates per treatment. The largest concentrations of NaCl the addition of the salt was made gradually to avoid osmotic shock. The number of leaves and leaf area were reduced in plants subjected to salinity from 30 to 45 mol m-3 NaCl, respectively. The production of fresh and dry matter were reduced from 60 mol.m-3 NaCl up to 36%. The concentration of soluble carbohydrates and total soluble proteins increased significantly only in plants exposed to 15 and 30 mol.m-3 and 30 mol.m-3 NaCl, respectively. The total phenol content increased in plants subjected to salinity from 30 mol.m-3 NaCl. The increase in the levels of total phenols, soluble carbohydrates and soluble proteins and the absence of reduced growth in seedlings subjected to 30 mol.m-3 NaCl indicates the activation of an efficient mechanisms of acclimatization of this stress magnitude. The levels of Na+ and Cl- increased in all parts of the plant were increased concentrations of salt in the nutrient solution. The high levels of Na+ and Cl- indicate the absence of extrusion mechanisms of these ions.