College of Tobacco Science, National Tobacco Cultivation and Physiology and Biochemistry Research Center, Key Laboratory for Tobacco Cultivation of Tobacco Industry, Henan Agricultural University, Zhengzhou, 450046, Henan, China.
International Center for Biosaline Agriculture, ICBA, P.O. Box 14660, Dubai, United Arab Emirates.
Sci Rep. 2024 Oct 26;14(1):25534. doi: 10.1038/s41598-024-76284-2.
Drought stress is an abiotic stressor that impacts photosynthesis, plant growth, and development, leading to decreased crop yields. Sodium hydrosulfide (NaHS), an exogenous additive, has demonstrated potential regulatory effects on plant responses to polyethylene glycol-induced drought stress in tobacco seedlings. Compared to the control, drought stress induced by 15 g/L PEG-6000 significantly reduced several parameters in tobacco seedlings: shoot dry weight (22.83%), net photosynthesis (37.55%), stomatal conductance (33.56%), maximum quantum yield of PSII (Fv/Fm) (11.31%), photochemical quantum yield of PSII (ΦPSII) (25.51%), and photochemical quenching (qP) (18.17%). However, applying NaHS, an HS donor, mitigated these effects, ultimately enhancing photosynthetic performance in tobacco seedlings. Furthermore, optimal NaHS concentration (0.4 mM) effectively increased leaf stomatal aperture, relative water content (RWC) and root activity, as well as facilitated the absorption of N, K, Mg and S. It also enhanced the accumulation of soluble sugar and proline content to maintain osmotic pressure balance under drought stress. Compared to drought alone, pretreatment with NaHS also bolstered the antioxidant defense system in leaves, leading to 22.93% decrease in hydrogen peroxide (HO) content, a 22.19% decrease in malondialdehyde (MDA) content and increased activities of ascorbate peroxidase (APX) by 28.13%, superoxide dismutase (SOD) by 17.07%, peroxidase (POD) by 46.99%, and catalase (CAT) by 65.27%. Consequently, NaHS protected chloroplast structure and attenuated chlorophyll degradation, thus mitigating severe oxidative damage. Moreover, NaHS elevated endogenous HS levels, influencing abscisic acid (ABA) synthesis and the expression of receptor-related genes, collaboratively participating in the response to drought stress. Overall, our findings provide valuable insights into exogenous NaHS's role in enhancing tobacco drought tolerance. These results lay the foundation for further research utilizing HS-based treatments to improve crop resilience to water deficit conditions.
干旱胁迫是一种非生物胁迫因子，会影响光合作用、植物生长和发育，导致作物产量下降。硫氢化钠（NaHS）作为一种外源性添加剂，已被证明对烟草幼苗中聚乙二醇诱导的干旱胁迫有潜在的调节作用。与对照相比，15g/L PEG-6000 诱导的干旱胁迫显著降低了烟草幼苗的几个参数：茎干重（22.83%）、净光合作用（37.55%）、气孔导度（33.56%）、PSII 最大量子产量（Fv/Fm）（11.31%）、PSII 光化学量子产量（ΦPSII）（25.51%）和光化学猝灭（qP）（18.17%）。然而，施加 HS 供体 NaHS 可以减轻这些影响，最终增强烟草幼苗的光合作用性能。此外，最佳 NaHS 浓度（0.4mM）有效增加叶片气孔开度、相对含水量（RWC）和根活力，并促进 N、K、Mg 和 S 的吸收。它还增加了可溶性糖和脯氨酸含量的积累，以在干旱胁迫下维持渗透压平衡。与单独干旱胁迫相比，NaHS 预处理还增强了叶片中的抗氧化防御系统，导致 H2O2 含量降低 22.93%，MDA 含量降低 22.19%，APX 活性提高 28.13%，SOD 活性提高 17.07%，POD 活性提高 46.99%，CAT 活性提高 65.27%。因此，NaHS 保护了叶绿体结构，减轻了叶绿素的降解，从而减轻了严重的氧化损伤。此外，NaHS 提高了内源性 HS 水平，影响了脱落酸（ABA）的合成和受体相关基因的表达，共同参与了对干旱胁迫的响应。总之，我们的研究结果为外源性 NaHS 增强烟草抗旱性提供了有价值的见解。这些结果为进一步研究利用 HS 处理来提高作物对水分亏缺条件的抗性奠定了基础。
