Growth, mineral composition, leaf chlorophyll and water relationships of two cherry varieties under NaCl-induced salinity stress

Growth, mineral nutrition, leaf chlorophyll and water relationships were studied in cherry plants (cv. 'Bigarreau Burlat' [BB] and 'Tragana Edessis' [TE]) grafted on 'Mazzard' rootstock and grown in modified Hoagland solutions containing 0, 25 or 50 mmol L-1 NaCl, over a period of 55 days. Elongation of the main shoot of the plants treated with 25 or 50 mmol L-1 NaCl was significantly reduced by approximately 29-36%, irrespective of the cultivar. However, both NaCl treatments caused a greater reduction in the dry weight of leaves and scion's stems in BB than in TE plants. Therefore, BB was more sensitive to salinity stress than TE. The reduction of leaf chlorophyll concentration was significant only when BB and TE plants were grown under 50 mmol L-1 NaCl. Osmotic adjustment permitted the maintenance of leaf turgor in TE plants and induced an increase in leaf turgor of BB plants treated with 25 or 50 mmol L-1 NaCl compared with 0 mmol L-1 NaCl. Concerning the nutrient composition of various plant parts, Na concentrations in all plant parts of both cultivars were generally much lower than those of Cl. For both cultivars, leaf Cl concentrations were much higher than the concentrations in stems and roots, especially in the treatments containing NaCl. Finally, the distribution of Na within BB and TE plants treated with NaCl was relatively uniform.