Plant Physiology and Biochemistry Laboratory, Department of Botany, Aligarh Muslim University, Aligarh 202002, India.
Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.
Biomolecules. 2021 Feb 18;11(2):305. doi: 10.3390/biom11020305.
The effects of nitric oxide (NO) as 100 µM sodium nitroprusside (SNP, NO donor) on photosynthetic-nitrogen use efficiency (NUE), photosynthetic-sulfur use efficiency (SUE), photosynthesis, growth and agronomic traits of rice ( L.) cultivars, Taipie-309 (high photosynthetic-N and SUE) and Rasi (low photosynthetic-N and SUE) were investigated under high temperature stress (40 °C for 6 h). Plants exposed to high temperature stress caused significant reduction in photosynthetic activity, use efficiency of N and S, and increment in HO and thiobarbituric acid reactive substance (TBARS) content. The drastic effects of high temperature stress were more pronounced in cultivar Rasi than Taipie-309. However, foliar spray of SNP decreased the high temperature induced HO and TBARS content and increased accumulation of proline and activity of ascorbate-glutathione cycle that collectively improved tolerance to high temperature stress more effectively in Taipie-309. Exogenously applied SNP alleviated the high temperature induced decrease in photosynthesis through maintaining higher photosynthetic-NUE and photosynthetic-SUE, activity of ribulose 1,5 bisphosphate carboxylase/oxygenase (Rubisco), and synthesis of reduced glutathione (GSH). The use of 2-4-carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxy-3-oxide (cPTIO, NO scavenger) substantiated the study that in the absence of NO oxidative stress increased, while NO increased photosynthetic-NUE and photosynthetic-SUE, net photosynthesis and plant dry mass. Taken together, the present investigation reveals that NO increased heat stress tolerance and minimized high temperature stress adversaries more effectively in cultivar Taipie-309 than Rasi by enhancing photosynthetic-NUE and SUE and strengthening the antioxidant defense system.
一氧化氮（NO）作为 100µM 硝普钠（SNP，NO 供体）对高温胁迫下（40℃处理 6 小时）水稻品种台粳 309（高光合氮和硫利用效率[SUE]）和 Rasi（低光合氮和 SUE）的光合-氮利用效率（NUE）、光合-硫利用效率（SUE）、光合作用、生长和农艺性状的影响。高温胁迫导致植物的光合活性、氮和硫的利用效率显著降低，同时羟基自由基（HO）和硫代巴比妥酸反应物（TBARS）的含量增加。与台粳 309 相比，高温胁迫对 Rasi 的影响更为显著。然而，叶面喷施 SNP 降低了高温诱导的 HO 和 TBARS 含量，增加了脯氨酸的积累和抗坏血酸-谷胱甘肽循环的活性，这些都使台粳 309 对高温胁迫的耐受性得到了更有效的提高。外施 SNP 通过维持较高的光合-NUE 和光合-SUE、核酮糖-1,5-二磷酸羧化酶/加氧酶（Rubisco）的活性以及还原型谷胱甘肽（GSH）的合成，缓解了高温诱导的光合作用下降。2-4-羧基苯基-4,4,5,5-四甲基咪唑啉-1-氧-3-氧化物（cPTIO，NO 清除剂）的使用证实了在没有 NO 的情况下氧化应激增加的研究，而 NO 增加了光合-NUE 和光合-SUE、净光合作用和植物干重。总之，本研究表明，通过提高光合-NUE 和 SUE 以及加强抗氧化防御系统，NO 增加了台粳 309 对热胁迫的耐受性，并比 Rasi 更有效地减轻了高温胁迫的不利影响。
