The current research was aimed to observe the interactive role of silicon-generated hydrogen sulfide (H2S) and nitric oxide (NO) on tolerance of pepper (Capsicum annum L.) plants to cadmium (Cd). Thus, the pepper plants were subjected to control (no Cd) or cadmium stress with and without Si supplementation. Significant decreases were found in plant dry weights, water potential, PSII maximum efficiency, glutathione (GSH), total chlorophyll, relative water content, Ca2+ and K+ concentrations and ascorbate, but there was a significant increase in H2O2, MDA, electron leakage (EL), proline, key antioxidant enzymes' activities, and endogenous Cd, NO and H2S in the Cd-stressed plants. Silicon enhanced Cd tolerance of the pepper plants by lowering the leaf Cd concentration, oxidative stress, enhancing the antioxidant defence system, leaf Si content, photosynthetic traits and plant growth as well as the contents of NO, proline and H2S. Furthermore, foliar-applied NO scavenger, cPTIO, and that of H2S, hypotaurine (HT), significantly decreased the levels of H2S alone, but cPTIO effectively reduced the concentrations of NO and H2S accumulated by Si in the Cd-stressed plants. The positive effect of Si was eliminated by cPTIO, but not by HT, suggesting that both molecules were involved in Si-induced improvement in Cd tolerance of the pepper plants.

中文翻译：

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通过上调一氧化氮和硫化氢的合成，外源供应的硅（Si）可提高辣椒（Capsicum annuum L.）的镉耐受性。

当前的研究旨在观察硅生成的硫化氢（H2S）和一氧化氮（NO）对辣椒（Capsicum annum L.）植物对镉（Cd）的耐受性的相互作用。因此，在添加和不添加Si的情况下，使辣椒植物经受对照（无Cd）或镉胁迫。植株干重，水势，PSII最大效率，谷胱甘肽（GSH），总叶绿素，相对水含量，Ca2 +和K +浓度和抗坏血酸含量均显着下降，但H2O2，MDA和电子泄漏（EL）显着增加），脯氨酸，关键的抗氧化酶活性以及镉胁迫植物中的内源Cd，NO和H2S。硅通过降低叶片中的Cd浓度，氧化胁迫，增强抗氧化防御系统，叶片中的Si含量来增强辣椒植物对Cd的耐受性，光合特性和植物生长以及NO，脯氨酸和H2S的含量。此外，叶面施用NO清除剂cPTIO，以及硫化氢，次牛磺酸（HT）可以显着降低单独的H2S水平，但是cPTIO有效降低了Si在镉胁迫植物中积累的NO和H2S浓度。Si的积极作用被cPTIO消除，但未被HT消除，表明这两个分子都参与了Si诱导的辣椒植物对Cd耐受性的改善。