Effects of exogenous Ca2+ on phenolic accumulation and physiological changes in germinated wheat (Triticum aestivum L.) under UV-B radiation

Exogenous Ca2+ affects the phenolic metabolism and physiological indices of germinated wheat under ultraviolet-B (UV-B) radiation, but the mechanism is unclear. The current study applied exogenous Ca2+ and Ca2+ channel blocker LaCl3 to the germinated wheat under UV-B radiation to unravel the role of Ca2+. The results indicated that total phenolic content (TPC) of the 4-day germinated wheat under UV-B radiation with CaCl2 (UV+B+Ca) treatment significantly increased by 10.3% as compared to the UV-B treatment. Gene expression levels of p-coumarate 3-hydroxylase, cinnamic acid 4-hydroxylase and caffeic acid O-methyltransferase were positively correlated with the content of ferulic and p-coumaric acids, respectively. Exogenous Ca2+ could significantly alleviate the membrane lipid peroxidation, activate the antioxidant enzymes and regulate the phytohormone level under UV-B radiation. This study suggested that exogenous Ca2+ participated in the phenolic metabolism and physiological regulation in germinated wheat under UV-B radiation.