State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China.
College of Environmental and Resource Science, Zhejiang Agricultural and Forestry University, Hangzhou, 311300, China.
Plant Physiol Biochem. 2020 Oct;155:374-383. doi: 10.1016/j.plaphy.2020.06.013. Epub 2020 Jul 27.
Salt stress inhibits rice productivity seriously. Nitric oxide (NO) is an endogenous signaling molecule in plants that can improve the resistance of rice to abiotic stresses. Previous studies also showed that nitrogen metabolism is essential for rice stress-tolerance. However, the physiological and molecular mechanisms by how NO affects the nitrogen metabolisms of rice seedlings remain unclear. A hydroponic experiment with two rice varieties, Jinyuan85 (salt tolerant) and Liaojing763 (salt sensitive), was carried out to explore whether NO could alleviate the negative effects of salt stress on nitrogen metabolism and increase salt resistance of rice seedlings. The results showed that (1) the application of NO alleviated the inhibitory effects of salt stress on plant height and biomass accumulation, and increased the nitrogen content of rice leaf. (2) the accumulation of the sucrose and proline was markedly increased in salt stress after application of NO, and peroxidase activities was increased by 107% and 67.7% for Jinyuan85 and Liaojing763, respectively. (3) NO significantly increased the activities of glutamate dehydrogenase, sucrose synthase and sucrose phosphate synthase in both rice varieties under salt stress. (4) Additionally, NO regulated the expression levels of AMT, NIA and SUT genes, but these regulation effects are different with rice varieties and treatments. The results suggested that NO mainly increased the glutamate dehydrogenase and peroxidase activities and sucrose accumulation to enhance the nitrogen metabolism and antioxidative capacity, and alleviated the negative effects of salt stress on rice performance.
盐胁迫严重抑制了水稻的生产力。一氧化氮（NO）是植物中的一种内源性信号分子，可提高水稻对非生物胁迫的抗性。先前的研究还表明，氮代谢对于水稻的抗逆性至关重要。然而，NO 如何影响水稻幼苗的氮代谢的生理和分子机制仍不清楚。通过水培实验，以两个水稻品种（金远 85 号和辽粳 763 号）为研究对象，探讨了 NO 是否可以减轻盐胁迫对氮代谢的负面影响并提高水稻幼苗的耐盐性。结果表明：（1）NO 的应用缓解了盐胁迫对株高和生物量积累的抑制作用，增加了水稻叶片的氮含量。（2）NO 处理后，盐胁迫下蔗糖和脯氨酸的积累明显增加，过氧化物酶活性分别增加了金远 85 号和辽粳 763 号的 107%和 67.7%。（3）NO 显著提高了两种水稻在盐胁迫下谷氨酸脱氢酶、蔗糖合酶和蔗糖磷酸合酶的活性。（4）此外，NO 调节了 AMT、NIA 和 SUT 基因的表达水平，但这些调控作用因水稻品种和处理方式而异。结果表明，NO 主要通过增加谷氨酸脱氢酶和过氧化物酶的活性以及蔗糖的积累来增强氮代谢和抗氧化能力，从而减轻盐胁迫对水稻性能的负面影响。
