LAUSR

Silicon has been widely reported to have a beneficial effect on improving plant tolerance to biotic and abiotic stresses. However, the mechanisms of Si in mediating responses to simultaneous salt and drought stresses are still poorly understood. Glycyrrhiza uralensis Fisch. is classified as a non-Si accumulator and suffered from salt and drought stresses. In this study, we investigated the long-term application of Si on Si content in G. uralensis roots, stems and leaves, leaf anatomy, ultrastructure, chlorophyll (Chl) content, gas exchange characteristics, relative water content, and growth of two-year-old plants under different salt and drought stresses. Silicon application resulted in a higher Si uptake in G. uralensis roots and more Si accumulation in leaves (especially deposition of Si on cell walls), and Si counteracted the adverse effects induced by salt and drought stresses on the leaf anatomy and ultrastructure. In plants treated with Si, a higher chlorophyll content, net photosynthetic rate and relative water content led to a higher growth rate and dry mass under salt and drought stresses compared with corresponding non-Si treated plants.