Effect of silicon in Pyropia yezoensis under temperature and irradiance stresses through antioxidant gene expression

Abstract

Increase in the temperature of seawater due to global warming is one of the major stress factors that has reduced seaweed, in particular Pyropia yezoensis, mariculture worldwide. In this milieu, silicon application has been reported to protect and heal the cells of thallus under stress conditions. The present study investigated the effect of in vitro different temperature and irradiance levels in P. yezoensis gametophytes and the potential mitigating effect of silicic acid (50 μM). The results revealed that the effect of temperature stress on the relative growth rate, the optimum photochemical efficiency of PS II (Fv/Fm), and the net photosynthetic rate (Pn) were minimal in the presence of silicon. The silica content in the thallus increased with increase in temperature, thus upregulating the expression of antioxidant genes. However, the effect of silicon was not characterized in P. yezoensis under irradiance treatments. The results suggest that silicon might effectively improve temperature stress tolerance in P. yezoensis.