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

Abstract

Waterlogging stress is a global factor limiting agricultural productivity. Silica nanoparticles (SiNPs) can improve the tolerance of plants to waterlogging stress, but their function and regulatory mechanisms in ginger are still unclear. Therefore, the effect of SiNP200 on ginger under waterlogging stress was investigated. Results showed that waterlogging stress had adverse effects on the growth, photosynthesis and plant water content of ginger seedlings. SiNP200 treatment significantly increased the net photosynthetic rate, reduced oxidative damage to leaf cells, and alleviated plant senescence and wilting. Additionally, SiNP200 application increased leaf relative water content by 9.61% under waterlogging stress, thus maintaining osmotic balance and increasing the water state of the whole plant. Besides, SiNP200 enhanced root growth and significantly increased root hydraulic conductivity (L_p, 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 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 a foundation for using SiNPs in plants to offset the negative effects of abiotic stress.