Nitric oxide (NO) and hydrogen sulfide (H₂S) since their discovery have proven to be game changing molecules in alleviating abiotic stress. They individually play role in plant stress management while the pathways of stress regulation through their crosstalk remain elusive. The current study focuses on investigating the interplay of NO and H₂S signalling in the amelioration of arsenate As(V) toxicity in rice seedlings and managing its growth, photosynthesis, sucrose and proline metabolism. Results show that As(V) exposure declined fresh weight (biomass) due to induced cell death in root tips. Moreover, a diminished RuBisCO activity, decline in starch content with high proline dehydrogenase activity and increased total soluble sugars content was observed which further intensified in the presence of Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME, an inhibitor of nitric oxide synthase-like activity), and DL-propargylglycine (PAG, an inhibitor of cysteine desulfhydrase activity). These results correlate with lower endogenous level of NO and H₂S. Addition of L-NAME increased As(V) toxicity. Interestingly, addition of SNP reverses effect of L-NAME suggesting that endogenous NO has a role in mitigating As(V) toxicity. Similarly, exogenous H₂S also significantly alleviated As(V) stress, while PAG further stimulated As(V) toxicity. Furthermore, application of H₂S in the presence of L – NAME and NO in the presence of PAG could still mitigate As(V) toxicity, suggesting that endogenous NO and H₂S could independently mitigate As(V) stress.

一氧化氮 (NO) 和硫化氢 (H ₂ S) 自发现以来已被证明是减轻非生物压力的改变游戏规则的分子。它们各自在植物压力管理中发挥作用，而通过它们的串扰调节压力的途径仍然难以捉摸。目前的研究重点是调查 NO 和 H ₂的相互作用S 信号在改善水稻幼苗中砷酸砷 (V) 毒性和管理其生长、光合作用、蔗糖和脯氨酸代谢中的作用。结果表明，由于诱导根尖细胞死亡，As(V) 暴露会降低鲜重（生物量）。此外，观察到 RuBisCO 活性降低，淀粉含量下降，脯氨酸脱氢酶活性高，总可溶性糖含量增加，在 Nω-硝基-L-精氨酸甲酯盐酸盐（L-NAME，硝酸盐抑制剂）存在下进一步加剧。氧化合酶样活性）和 DL-炔丙基甘氨酸（PAG，半胱氨酸脱硫酶活性抑制剂）。这些结果与较低的内源性 NO 和 H ₂水平相关S. 添加 L-NAME 增加了 As(V) 毒性。有趣的是，添加 SNP 会逆转 L-NAME 的作用，表明内源性 NO 在减轻 As(V) 毒性中起作用。同样，外源 H ₂ S 也显着减轻了 As(V) 应激，而 PAG 进一步刺激了 As(V) 毒性。此外，在 L-NAME 存在下应用 H ₂ S 和在 PAG 存在下应用 NO 仍然可以减轻 As(V) 毒性，表明内源性 NO 和 H ₂ S 可以独立地减轻 As(V) 压力。