气孔导度控制叶片对碳源(CO₂)的获取能力，通过影响光合作用对作物生产能力发挥作用。针对稻田过量施氮导致氮素利用效率趋缓的现状，本研究对高氮投入时促进氮素吸收利用的调控策略进行研究。利用气孔钾通道基因ZmK2;1超表达水稻遗传材料，设置氮缺乏(LN，不施氮)、中量或减少氮投入(MN，200 kg/hm²)和过量施氮(HN，350 kg/hm²) 3个处理的田间试验，对ZmK2;1超表达植株在生育后期的氮素营养特征和生产特性进行研究。结果表明：ZmK2;1超表达能改善水稻植株在各氮肥施用水平下的产量形成特征，差异化提升植株氮钾含量，优化植株整体和剑叶的氮素营养特征，促进植株生物量积累，其剑叶在生育后期保持较高的光合效率(Pn)和气孔导度(g_s)。另外，ZmK2;1基因超表达有利于中量氮投入和过量施氮下水稻氮素利用效率的提升，尤其在过量施氮条件下，该基因过表达仍能够促进氮肥农学效率(AE_N)、氮素生理效率(PE_N)和氮素收获指数(NHI)。可见，利用气孔钾通道ZmK2;1在水稻中超表达可以调节植株和关键功能叶氮钾比，促进各施氮水平下的光合效率的同时提升水稻产量；在过量施氮时，依然能保持较高的光合同化能力，提升水稻氮素利用率和增产潜力。

Stomatal conductance controls the ability of leaves to acquire carbon sources (CO₂), and it is closely related to crop productivity by affecting photosynthesis. In view of the current situation of slowing N use efficiency caused by N fertilizer overuse in paddy soil, it is necessary to study the regulation strategy of high N fertilizer input to promote N absorption and utilization. Therefore, ZmK2;1 overexpression transgenic lines were used to set up a field experiment of three conditions including N deficient (LN, no N application), moderate or reduced N input (MN, 200 kg/hm²) and N fertilizer overuse (HN, 350 kg/hm²), which were used to study the N nutrition characteristics and production traits in the later growth stage. The results show that ZmK2;1 overexpression can improve the yield characteristics for rice plants under each N application level. At the same time, the content of N and K are increased differentially, it optimizes nitrogen nutrition characteristics of the whole plant and key functional leaves (flag leaves), and promotes the accumulation of plant biomass. Besides, the flag leaf of ZmK2;1 overexpression plant maintains a promising photosynthetic rate (Pn) and stomatal conductance (g_s) during the later growth period. In addition, ZmK2;1 overexpression can promote the N use efficiency of rice under the N fertilizer moderate input and N fertilizer overuse, especially under the condition of N fertilizer overuse, the overexpression of this gene can still promote agronomic N use efficiency (AE_N), physiological N use efficiency (PE_N) and N harvest index (NHI). Obviously, overexpression of the stomatal potassium channel ZmK2;1 in rice can regulate the N/K ratio of plants and key functional leaves, promote photosynthetic rate, and improve the rice yield under different N application. In particular, under the condition of N fertilizer overuse, it can still maintain a high photosynthesis assimilation ability, and plays a positive effect on performing the N use efficiency and yield-increasing potential of rice.

S511.2；Q945.1

中国科学院战略性科技先导专项(A 类) (XDA24010201)