Effects of silicon on photosynthetic traits of Saponaria officinalis under drought stress

Experiments was conducted by normal conditions, mild drought stress, severe drought stress and different concentrations of silicon treatment on Saponaria officinalis, and photosynthetic parameters and chlorophyll content of leaves were determined. The photosynthetic curve was fitted, and the photoresponse parameters under various treatments were obtained. The results showed that the light compensation point (LCP) of S. officinalis leaves decreased, and the rest of the photosynthetic physiological indexes increased by silicon application under normal condition; The net photosynthetic rate(Pn), chlorophyll content, maximum net photosynthetic rate(Amax), dark respiration rate(Rd), light saturation point (LSP) and apparent quantum efficiency(AQY) of S. officinalis leaves increased, and stomatal conductance(Gs), transpiration rate(Tr) and LCP decreased by silicon application under mild and severe drought stress. Notably, 0.3, 0.4 g SiO2·kg-1 were most effective. The results indicated that the application of silicon could enhance the photosynthesis and respiration of the S. officinalis, so as to make better use of the light energy and regulate the metabolism and significantly alleviate the damage caused by the drought.