Organic solute status and water relations of some salt-tolerant and salt-sensitive accessions of lentil (Lens culinaris)

Three salt-tolerant (ILL 6451, ILL 6788, ILL 6793) and two saltsensitive (ILL 6439 and ILL 6778) accessions of lentil (Lens culinaris Medic.) were grown for 42 days in sand culture salinized with 0 or 30 mol m-3 NaCl in full strength Rorison nutrient solution in order to determine the physiological/biochemical mechanisms responsible for their salt tolerance. All three salt-tolerant accessions produced significantly greater shoot and root biomass than the two salt-sensitive accessions after the salt treatment. Of the salt-tolerant accessions, ILL 6451 and ILL 6788 had significantly higher leaf water potentials but lower osmotic potentials than the other accessions under saline conditions. Leaf diffusive resistance and epicuticular wax content were significantly higher in the two sensitive accessions compared with the tolerant accessions after the salt treatment. Leaf soluble proteins decreased due to NaCl treatment but to the same extent in both tolerant and sensitive accessions. Total free amino acids and nonreducing sugars were relatively low in the two salt-sensitive accessions after the salt treatment. Reducing sugars of the tolerant accessions remained unaffected due to NaCl, whereas those of ILL 6439 increased and of ILL 6778 decreased. Leaf free amino acids and non-reducing sugars appeared to have contributed, to some extent, to the salt tolerance of tolerant accessions.