Enhancing antioxidant capacity and regulating aquaporin genes expression for better water absorption by nano-silicon

Abstract

To clarify the mitigation mechanism of silicon nanoparticles (SiNPs) on Jerusalem artichoke (Helianthus tuberosus L.) under drought stress, we used the 'Qingyu' variety of Jerusalem artichoke as the research material. We conducted a greenhouse pot experiment to explore the effects of foliar spraying with a 100 mg·L⁻¹ nano-silicon (SiNP100) solution on the growth and physiological processes of Jerusalem artichoke seedlings subjected to drought stress, with the soil's relative water holding capacity controlled between 40 % and 45 %. The results indicated that, compared to drought stress alone, the application of SiNP100 (DS+SiNP100) significantly alleviated the growth inhibition of Jerusalem artichoke, while enhancing photosynthesis, chlorophyll fluorescence, and chlorophyll content in the leaf. Additionally, the levels of malondialdehyde (MDA), hydrogen peroxide (H₂O₂), and superoxide radicals (O₂∙⁻) were reduced. Conversely, the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), were markedly increased. Under the DS+SiNP100 treatment, the bound water content, total water content, and relative water content increased by 44.29 %, 12.09 %, and 5.42 %, respectively. In addition, the DS+SiNP100 treatment mitigated the increase of TIP1–5 and TIP2–2 induced by drought stress at 35 days, and improved the drought stress-induced inhibition of the expression levels of PIP2–7 and TIP2–7 genes. This may be attributed to the enhanced water status of the plants due to the DS+SiNP100 treatment. It is speculated that the AQP gene may play a role in regulating plant water status in response to SiNP100. In summary, foliar spraying of SiNPs significantly improves the drought resistance of Jerusalem artichokes. This study offers a theoretical foundation for utilizing SiNPs in the drought-resistant cultivation of Jerusalem artichokes.