Bifunctional pectin-silica nanocomposites for mitigating drought stress and promoting ginseng growth

Drought stress is one of the most serious abiotic stressors during the ginseng growth period and has significantly reduced ginseng yield and quality. Conventional water retention agents (WRAs) improve drought resilience but face poor biodegradability and environmental risks. Pectin offers great water retention properties but suffers from weak stability. Herein, we developed a bifunctional nanocomposite by hybridizing mesoporous silica nanoparticles with pectin (PMSNs). In this system, pectin as an eco-friendly and biodegradable natural polymer can effectively retain water. Mesoporous silica nanoparticles (MSNs) could enhance plant resistance and promote growth. And the modification of pectin onto MSNs improved their stability. The experimental results revealed that PMSNs (2 g kg^-1) significantly increased soil moisture and nutrient content for promoting plant growth under drought conditions. Additionally, they enhanced antioxidant enzyme activity and proline (PRO) content, reduced malondialdehyde (MDA) content, and alleviated oxidative stress caused by drought. This work provides a strategy to enhance drought tolerance in ginseng, combining nanotechnology with natural polymers to overcome the drawbacks of conventional WRAs.