SiNPs improves the waterlogging tolerance of ginger by increasing water absorption in root system

Waterlogging stress is a major global constraint on agricultural productivity. While silica nanoparticles (SiNPs) have been shown to enhance plant tolerance to waterlogging, their mechanisms of action in ginger remain poorly understood. This study aims to elucidate the role of SiNP200 in mitigating waterlogging stress, providing a foundation for utilizing SiNPs to counteract the detrimental effects of abiotic stress in plants. The results showed that waterlogging stress had adverse effects on the growth, photosynthetic and plant water content of ginger seedlings. SiNP200 treatment significantly increased the net photosynthetic rate, reduced the oxidative damage of leaf cells, and alleviated plant senescence and wilting. Additionally, SiNP200 application can increase leaf relative water content by 9.61% under waterlogging stress, thus maintain osmotic balance and increase water state of the whole plant. Besides, SiNP200 enhanced root growth and significantly increased root hydraulic conductivity (by up to 113.46%) in ginger seedlings. This improvement was further supported by the upregulated expression of aquaporin genes, including ZoPIP1;3, ZoTIP2;2, and ZoNIP2;6, which collectively facilitated water absorption and elevated tissue water content. Under waterlogging conditions, the activities of anaerobic respiratory enzymes, such as alcohol dehydrogenase (ADH) and lactate dehydrogenase (LDH), significantly increased. Following SiNP200 treatment, the activities of ADH and LDH were further enhanced, potentially intensifying the anaerobic respiration in ginger seedling roots. This enhancement may enable the roots to better adapt to the dramatic reduction in soil oxygen levels, thereby improving their tolerance to waterlogged environments. Therefore, this study will help to better understand the role of SiNP200 in alleviating waterlogging stress and provide foundation for the use of SiNPs in plants to offset the negative effects of abiotic stress.