Effect of silicon supply on growth and photosynthetic characteristics of tall fescue seedlings under different salt concentrations conditions

Tall fescue(Festuca arundinacea) frequently grows in saline soil, or in soil with a high potential for salinization due to long-term and frequent irrigation. A pot experiment was conducted to investigate the effect of Si on seed germination, biomass, and photosynthetic characteristics in stage two tall fescue seedlings under different salinization conditions. The results showed that seed germination, biomass, and photosynthetic characteristics of the seedlings was significantly affected by salt concentration, variety, silicon supply, interactions between salinization conditions and species, and interactions between silicon supply and salt concentrations. The seedling rate, the seedling survival rate, biomass, photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), and stomatal limitation percentage (Ls) of K31 and XD tended to decrease with increase in salinity. Intercellular CO2 concentration (Ci) tended to increase with increase in salinity. Silicon significantly increased the seedling rate of XD and K31 and seedling survival rate and seedling biomass. Pn, Gs, and Ls decreased Ci and Tr under salinization conditions (P＜0.05). The sensitivity of XD and K31 to silicon differed under the same salinization conditions. This indicated that the effects of silicon supply on tall fescue growth in saline conditions are closely related to resistance.