Silica Nanoparticles Improve Drought Tolerance in Ginger by Modulating the AsA-GSH Pathway, the Glyoxalase System and Photosynthetic Metabolism

Drought stress (DS) is a primary environmental factor that limits the production of ginger (Zingiber officinale Roscoe). Silica nanoparticles (SiNPs) have been shown to enhance drought resistance in ginger by modulating water relations. However, the specific impact of SiNPs on the antioxidant and glyoxalase system responses to DS remains unclear. To investigate the impact of SiNP100 on photosynthetic and antioxidant metabolism in ginger under DS, four treatments were designed in this study: control (CK), drought stress (DS), silica nanoparticles (SiNP100) application, and the combined treatment of DS and SiNP100 (DS + SiNP100). The results showed that SiNP100 alleviated DS-induced damage by improving photosynthetic parameters, chlorophyll content, and the efficiency of photosystems I and II. DS significantly increased the levels of reactive oxygen species (ROS), malondialdehyde (MDA), and methylglyoxal (MG), thereby inducing oxidative stress. SiNP100 mitigated this effect by reducing ROS accumulation and enhancing the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). Furthermore, SiNP100 boosted the ascorbate–glutathione (AsA-GSH) cycle by increasing the activities of key enzymes (APX, DHAR, MDHAR, and GR) and upregulating the expression of ZoDHAR2, ZoAPX1, and ZoGR2. This leads to higher ascorbate and glutathione levels in ginger. SiNP100 also bolstered the glyoxalase system, as evidenced by increased activities of glyoxalase I (Gly I) and glyoxalase II (Gly II), alongside the upregulation of ZoGLY1 expression, thereby promoting methylglyoxal (MG) detoxification. In conclusion, SiNP100 enhances drought tolerance in ginger by reinforcing the antioxidant defense system, AsA-GSH cycle, and methylglyoxal detoxification system, thereby protecting photosynthetic metabolism and promoting growth.