Optimum Ca(NO3)2 supply develops salt tolerance in NaCl-stressed Cyclocarya paliurus seedlings

摘要

The effect of varying Ca(NO3)2 supply (0, 6, 12, and 18 mM) on growth, ion uptake, leaf chlorophyll concentration and photosynthesis of NaCl-stressed (85 mM NaCl) Cyclocarya paliurus seedlings was investigated. Addition of Ca(NO3)2 stimulated the shoot growth more than root growth. Ca(NO3)2 supply increased K+ and Ca2+ concentration, whereas the Na+ transport to the leaves was inhibited. There was a strong increase in the K+/Na+ ratio in the leaves of Ca(NO3)2-treated seedlings. Leaf chlorophyll concentration and photosynthesis rate were low, but both factors were enhanced by 12 mM Ca(NO3)2. Therefore, moderate Ca(NO3)2 supply (12 mM) had optimal effects on growth and metabolism of NaCl-stressed C. paliurus seedlings.