Abstract

GARCIA, Marina  and  MEDINA, Ernesto. Ion and organic solute accumulation in two sugarcane  genotypes, salt stressed with or without calcium supply. Bioagro [online]. 2009, vol.21, n.1, pp.3-14. ISSN 1316-3361.

Two sugar cane genotypes differing in salt tolerance (‘PR692176’, salt tolerant and ‘V78-1’, salt sensitive) were evaluated to  know the role of the Na⁺ and/or  Cl^- exclusion, the K/Na selectivity, and the accumulation of organic solutes in their differential salt tolerance. The plants grew four months under controlled conditions, and during the last two months, they were subjected to salt stress using simple sodium salts, with or without additional calcium supply. The concentration of Na⁺, K⁺, Cl^-, soluble sugars and proline was determined in roots and in leaves differing in age. In the salt stressed plants, the foliar concentration of K⁺ was reduced, and Na⁺ y/o Cl^- was increased, but the last two ions were accumulated mainly in the oldest leaves and the sheath. The foliar concentration of  Na⁺ in NaCl-treated plants was higher than in Na₂SO₄-treated plants. Calcium supply to simple salts increased the concentrations of K⁺ and decreased Na⁺ y/o Cl^- contents. The non-reducing sugars and proline contents were increased with salinity stress in both genotypes. Under saline stress, PR692176 showed a lower foliar concentration of  Na⁺ and  Cl^-, and higher K/Na ratio in leaves, in addition to a higher content  of non-reducing sugars, than V78-1. These results indicate that salt tolerance in sugar cane is related to a better exclusion capacity and a higher ability to accumulate non-reducing sugar for osmotic adjustment.

Keywords : Salinity; NaCl; proline; reducing and non reducing sugars.