Abstract
Silicon effectively alleviates the damage caused by salt stress in plants and can improve plant salt tolerance. However, the details of the mechanism by which silicon improves salt tolerance of liquorice are limited, and the effects of foliar application of silicon on different liquorice species under salt stress are not known. Here, the effects of foliar spray of silicon on the growth, physiological and biochemical characteristics, and ion balance of Glycyrrhiza uralensis Fisch. and Glycyrrhiza inflata Bat. were investigated. High salt stress resulted in the accumulation of a large amount of Na+, decreased photosynthetic pigment content, perturbed ion homeostasis, and eventually inhibited the both liquorice species growth. These effects were more pronounced in G. uralensis, as G. inflata is more salt tolerant than G. uralensis. Foliar spraying of silicon effectively reduced the decomposition of photosynthetic pigments, improved gas exchange parameters, and promoted photosynthesis. It also effectively inhibited lipid peroxidation and electrolyte leakage and enhanced osmotic adjustment of plants. Further, silicon application increased the K+ concentration, reduced Na+ absorption, transport and accumulation in the plants. The protective effects of silicon were more pronounced in G. uralensis than those in G. inflata. In conclusion, silicon reduces Na+ absorption, improves ion balance, and alleviates the negative effects of salt stress in the two liquorice species studied, but the effect is liquorice species-dependent. These findings may inform novel strategies for protecting liquorice plants against salt stress and also provide a theoretical basis for the evaluation of salt tolerance and the scientific cultivation of liquorice.
Glycerol foliar application improves salt tolerance in three pistachio rootstocks
