Deng Rui, Zheng Dianfeng, Feng Naijie, Khan Aaqil, Zhang Jianqin, Sun Zhiyuan, Li Jiahuan, Xiong Jian, Ding Linchong, Yang Xiaohui, Huang Zihui, Liao Yuecen
College of Coastal Agriculture Sciences, Guangdong Ocean University, Zhanjiang 524088, China.
South China Center of National Saline-Tolerant Rice Technology Innovation Center, Zhanjiang 524088, China.
Plants (Basel). 2025 Jan 13;14(2):211. doi: 10.3390/plants14020211.
Salt stress is an important factor affecting the growth and development of rice, and prohexadione calcium (Pro-Ca) plays an important role in alleviating rice salt stress and improving rice yield. However, there are few studies on how Pro-Ca improves rice yield under salt stress by regulating the source-sink metabolism. In this study, we used Guanghong 3 (salt-tolerant variety) and Huanghuazhan (salt-sensitive variety) as experimental materials to investigate the dynamic changes in the synthesis and partitioning of nonstructural carbohydrates among source-sink, the dynamic changes in related enzyme activities, the effects of the source-sink metabolism on yield in rice under salt stress and the effect of Pro-Ca during the filling period. The results of this study showed that Pro-Ca improved photosynthetic efficiency by increasing leaf photosynthetic gas exchange parameters and other stomatal factors on the one hand and, on the other hand, promoted sugar catabolism and reduced sugar synthesis by increasing leaf sucrose synthase activity and decreasing sucrose phosphate synthase activity, alleviating the inhibitory effect of high concentrations of sugars in the leaves on photosynthesis. Meanwhile, Pro-Ca promotes the transport of sugars from source (leaves) to sink (seeds), increases the sugar content in the seeds, and promotes starch synthesis in the seeds by increasing starch phosphorylase, which promotes seed filling, thus increasing the number of solid grains on the primary and secondary branches of the panicle in rice, increasing the 1000-grain weight, and ultimately increasing the seed setting rate and yield. These results indicated that Pro-Ca alleviated the inhibitory effect of salt stress on rice leaf photosynthesis through stomatal and non-stomatal factors. Meanwhile, Pro-Ca promotes the transport of rice sugars from source to sink under salt stress, regulates the source-sink relationship during the filling period of rice, promotes starch synthesis, and ultimately improves rice yield.
盐胁迫是影响水稻生长发育的重要因素，而调环酸钙（Pro-Ca）在缓解水稻盐胁迫和提高水稻产量方面发挥着重要作用。然而，关于Pro-Ca如何通过调节源库代谢来提高盐胁迫下水稻产量的研究较少。在本研究中，我们以广恢3号（耐盐品种）和黄华占（盐敏感品种）为试验材料，研究了盐胁迫下水稻源库间非结构性碳水化合物合成与分配的动态变化、相关酶活性的动态变化、源库代谢对产量的影响以及灌浆期Pro-Ca的作用。本研究结果表明，Pro-Ca一方面通过提高叶片光合气体交换参数等气孔因素来提高光合效率，另一方面通过提高叶片蔗糖合酶活性和降低蔗糖磷酸合酶活性来促进糖分分解代谢并减少糖分合成，减轻叶片中高浓度糖分对光合作用的抑制作用。同时，Pro-Ca促进糖分从源（叶片）向库（种子）的运输，增加种子中的糖分含量，并通过提高淀粉磷酸化酶促进种子淀粉合成，从而促进种子灌浆，进而增加水稻穗部一次枝梗和二次枝梗上的实粒数，增加千粒重，最终提高结实率和产量。这些结果表明，Pro-Ca通过气孔和非气孔因素减轻了盐胁迫对水稻叶片光合作用的抑制作用。同时，Pro-Ca促进了盐胁迫下水稻糖分从源到库的运输，调节了水稻灌浆期的源库关系，促进了淀粉合成，最终提高了水稻产量。
