Mechanisms of salt stress tolerance in two rose rootstocks:: Rosa chinensis 'Major' and R-rubiginosa

The responses of two rose rootstocks Rosa chinensis 'Major' and R. rubiginosa were investigated under salt stress. The distribution of chloride and sodium ions in all plant parts was determined. The salt treatments were applied through irrigation water containing 0, 5, 10, 20 and 30 mM NaCl. Necrosis on the leaves as a result of the NaCl treatments was observed with in rootstocks after two months. Leaf injury was more pronounced in R. chinensis 'Major' than R. rubiginosa. The rootstock R. rubiginosa showed a higher tolerance to the NaCl stress than R. chinensis 'Major'. The survival of the plants under increased NaCl stress as well as the extent of leaf injury could be used in the determination of tolerance of the rose genotypes. The lower older leaves contained higher concentrations of Cl- than the young upper leaves. Leaf samples had higher concentrations of Cl- than stem samples taken from the same positions. The roots contained higher amounts of Cl- than the stem samples. The plants accumulated higher amounts of Cl- in comparison with Na+. The lower leaves of R. chinensis 'Major' had higher amounts of Na+ than in all other parts whereas R. rubiginosa had higher concentrations of Na+ in the roots than in all other parts. (C) 2001 Elsevier Science B.V. All rights reserved.