Responses of Hydraulic-Related Leaf and Root Eco-Physiological Traits to Silicon Application on the Salinity Stress of Oat Seedlings

Aims Silicon fertilizer has been widely used in agriculture and been found to mitigate salinity stress in plants. However, studies that have examined the underlying mechanisms of silicon alleviation relating to hydraulics found that the plants respond in a various way. Thus, how silicon affected the hydraulic-related leaf and root traits need to be further studied. Methods In this study, a pot experiment in which NaCl and Si were applied to the plants was conducted in a greenhouse to examine how the addition of silicon would mitigate plant growth and affect the related traits of oats subjected to salinity. A variety of plant eco-physiological traits were measured after around two months of growth. Results The addition of silicon significantly decreased the Gs, increased leaf structural carbon, decreased specific root length (SRL), and had no significant effects on leaf non-structural carbon, leaf morphological traits and leaf chlorophyll in salinity-stressed oat. The PCA analysis clearly showed the Gs, SRL and leaf structural carbon represented the three independent traits in explaining the variation following the silicon addition. Conclusion The addition of silicon alleviates salinity-stress oat through three hydraulic-related leaf and root eco-physiological traits, which suggests that the plant hydraulic mechanisms are activated with silicon fertilizing in salinity.