Exogenous calcium-alleviating effect on sodium salt-induced phytotoxicity associated with changes in photosynthetic characteristics of wheat seedlings.

To evaluate the Ca-alleviating effect on sodium salt-induced phytotoxicity, wheat ( Triticum aestivum L.) cultivar Xihan 3 seedlings were treated with 150 mM NaCl, CaCl ₂ (0.1, 0.5, and 1 mM), Ca ²⁺ -channel blocker LaCl ₃ , and/or Ca ²⁺ chelator, ethylene glycol tetraacetic acid (EGTA) alone or in combination, to investigate seedling growth and photosynthetic characteristics. NaCl (150 mM) exposure alone suppressed a growth of seedling, weakened photosynthetic efficiency and chlorophyll (Chl) fluorescence parameters, reduced photosynthetic pigments, Ca ²⁺ and calmodulin (CaM) contents, and downregulated TaCaM expression in wheat leaves. The opposite changes of these parameters were caused by 0.5 or 1 mM CaCl ₂ treatments alone. Moreover, 0.5 or 1 mM CaCl ₂ application effectively alleviated sodium salt-induced changes of these parameters, which was blocked by LaCl ₃ or EGTA. Therefore, exogenous Ca presence effectively promoted the growth of NaCl-stressed wheat seedlings through the enhancement of photosynthesis and Chl synthesis mediated by the Ca-CaM signal.
Competing Interests: The authors declare that they have no conflict of interest.
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