The cultivarietal differences in salt-tolerance and the effect of NaCl on the absorption and translocation of K, Ca and Mg ions in Phaseolus vulgaris L.

Salt tolerance was compared among 19 cultivars of Phaseolus vulgaris L. grown in nutrient solutions containing 0, 40, and 80 mmol . liter(-1) NaCl. The relative growth indices (growth ratio of NaCl-treated plants relative to that of untreated plants) of the shoots correlated negatively to the Na+ and Cl- concentrations in the leaflets, and positively to the concentrations of these elements in the roots. The indices showed higher correlation coefficients with Na+ than with Cl- concentrations in every organ. Among the cultivars tested 'Shuttle' and 'Himetebou' were most tolerant, 'Shirokinugasa' and 'Chang Jiang' were least tolerant to the high level of NaCl in the nutrient solution. Salt tolerance of bean cultivars depends on the plants' ability to restrict the absorbed Na+ to the root and to keep the Na+ concentration in the leaflets low. Supplying NaCl to the nutrient solution caused an increase in 1) the concentrations of K+ and Ca2+ in the plant, and 2) the transport of K+ from roots to shoots, of Ca2+ from the stem + petioles to the leaflets and of Mg2+ from roots to the leaflets. There were correlations between salt tolerance and changes of K+, Ca2+, and Mg2+ concentrations in plant parts of NaCl-treated plants.