Gao Xin-Qi, Li Chun-Guang, Wei Peng-Cheng, Zhang Xin-Yan, Chen Jia, Wang Xue-Chen
State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100094, People's Republic of China.
Plant Physiol. 2005 Nov;139(3):1207-16. doi: 10.1104/pp.105.067520. Epub 2005 Oct 21.
Stomatal movement is important for plants to exchange gas with environment. The regulation of stomatal movement allows optimizing photosynthesis and transpiration. Changes in vacuolar volume in guard cells are known to participate in this regulation. However, little has been known about the mechanism underlying the regulation of rapid changes in guard cell vacuolar volume. Here, we report that dynamic changes in the complex vacuolar membrane system play a role in the rapid changes of vacuolar volume in Vicia faba guard cells. The guard cells contained a great number of small vacuoles and various vacuolar membrane structures when stomata closed. The small vacuoles and complex membrane systems fused with each other or with the bigger vacuoles to generate large vacuoles during stomatal opening. Conversely, the large vacuoles split into smaller vacuoles and generated many complex membrane structures in the closing stomata. Vacuole fusion inhibitor, (2s,3s)-trans-epoxy-succinyl-l-leucylamido-3-methylbutane ethyl ester, inhibited stomatal opening significantly. Furthermore, an Arabidopsis (Arabidopsis thaliana) mutation of the SGR3 gene, which has a defect in vacuolar fusion, also led to retardation of stomatal opening. All these results suggest that the dynamic changes of the tonoplast are essential for enhancing stomatal movement.
气孔运动对于植物与环境进行气体交换至关重要。气孔运动的调节有助于优化光合作用和蒸腾作用。已知保卫细胞中液泡体积的变化参与了这一调节过程。然而，关于保卫细胞液泡体积快速变化的调节机制，人们了解甚少。在此，我们报告复杂的液泡膜系统的动态变化在蚕豆保卫细胞液泡体积的快速变化中起作用。当气孔关闭时，保卫细胞含有大量小液泡和各种液泡膜结构。在气孔开放期间，小液泡和复杂的膜系统相互融合或与较大的液泡融合，形成大液泡。相反，在气孔关闭过程中，大液泡分裂成较小的液泡，并产生许多复杂的膜结构。液泡融合抑制剂（2s,3s）-反式-环氧琥珀酰-L-亮氨酰胺-3-甲基丁烷乙酯显著抑制气孔开放。此外，拟南芥中SGR3基因的突变导致液泡融合缺陷，也导致气孔开放延迟。所有这些结果表明，液泡膜的动态变化对于增强气孔运动至关重要。
