钾通道ZmK2;1在水稻中超表达提升水稻氮素利用潜力

气孔运动与光合同化效率密切相关,通过影响叶片对碳源的获取能力对植株生长发育和籽粒生产发挥作用。针对稻田过量施氮导致的环境风险和氮素利用效率趋缓的现状,研究高氮投入时促进氮素吸收利用的调控策略非常必要。本研究利用气孔钾通道基因ZmK2;1超表达水稻遗传材料,设置N 缺乏(LN, 不施氮)、中量或减少氮投入(MN, 200 kg hm_^-2)和过量施氮(HN, 350 kg hm_^-2)三个施氮水平的田间试验,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,提升植株氮钾含量和生物量,改善植株的氮素营养特征,其剑叶在生育后期保持较高的光合效率和气孔导度。另外,ZmK2;1基因超表达能促进水稻氮素利用效率的提升,尤其在过量施氮(HN)条件下,该基因过表达仍能够改善其氮素利用。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了水稻产量；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。

Overexpression of Potassium Channel ZmK2;1 in Rice Improves Nitrogen Utilization Potential

Stomatal movement is closely related to photosynthesis efficiency, and plays a role in plant growth and grain production by affecting the ability of leaves to acquire carbon sources. In view of the current situation of environmental risks and slowing N use efficiency caused by N fertilizer overuse in paddy soil, it was necessary to study the regulation strategy of high N fertilizer input to promote N absorption and utilization. Therefore, ZmK2;1 overexpression transgenic lines was used to set up a field experiment of three N levels including N deficient (LN, no N application), moderate or reduced N input (MN, 200 kg hm_^-2) and N fertilizer overuse (HN, 350 kg hm_^-2), which was used to study the N nutrition characteristics and production traits in the later growth stage. The results showed that ZmK2;1 overexpression could improve the yield characteristics for rice plants under each N application levels. At the same time, the content of N, K and plant biomass were increased, and the N nutrition characteristics of plants were improved. Besides, the flag leaf of ZmK2;1 overexpression plants maintained a good photosynthetic rate during the later growth period. In addition, ZmK2;1 overexpression could promote the N use efficiency of rice for each N application level, especially under the condition of N fertilizer overuse (HN), the overexpression of this gene could still improve its N utilization. Overexpression of the stomatal potassium channel ZmK2;1 in rice could regulate the N-K ratio of plants and key functional leaves, promote photosynthetic rate under various N application levels, and improve rice yield. In the case of excessive nitrogen application, it can still maintain a high photosynthesis ability, and improve the N use efficiency and yield-increasing potential of rice.