Light, Stomatal Function and Energy Transduction in Guard Cells

保卫细胞中的光、气孔功能和能量传导

• 批准号: 8904254
• 负责人: Eduardo Zeiger
• 金额: $ 25.96万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-09-01 至 1992-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8904254&HistoricalAwards=false
• 关键词: Light; Stomatal; Function; Energy; Transduction

Stomata regulate gas exchange in leaves, thus affecting productivity and the water balance of the plant. Stomatal control depends on sensory transduction by guard cells of internal and external stimuli, translating information about prevailing conditions in the leaf environment to modulation of the size of stomatal apertures. The overall objective of this research program is to understand the signal perception, metabolic transduction, and aperture regulation during the movements of stomata in response to light. Recent studies have shown that light activates proton pumping at the guard cell plasmalemma via two different transduction pathways, one activated by a blue light photoreceptor and the other by the guard cell chloroplast. The aim of this proposal is the detailed characterization of the sensory transduction steps involved in pump activation. Using the electrophysiological technique of patch clamping, metabolic and photobiological features of the two pathways will be investigated, including critical concentrations of ATP and other cofactors, fluence-rate dependence, specific pharmacological properties, and interactive features between the two pathways in connection with the guard cell response to solar radiation. The identity of the blue light photoreceptor will be investigated by spectroscopic analysis at low and room temperature. Gas exchange techniques with intact leaves will be used to correlate resolved features at the subcellular and cellular level with stomatal performance under physiological conditions. Stomata are pores in the surface of a leaf which regulate the passage of water and gasses into and out of the leaf's tissue. Proper traffic through the stomata is vital for the plant's ability to conduct photosynthesis and maintain its water balance. The stomata open and close in response to environmental stimuli. The results of this research will enhance our understanding of the cellular mechanisms which regulate the movements of stomata, and more generally, will increase basic knowledge of the mechanisms of sensory transduction and ion transport in plant cells.

气孔调节叶片中的气体交换，从而影响植物的生产力和水分平衡。气孔控制依赖于保卫细胞对内部和外部刺激的感觉转导，将有关叶环境中普遍情况的信息转化为气孔大小的调节。这项研究的总体目标是了解气孔对光的响应过程中的信号感知、代谢转导和孔径调节。最近的研究表明，光通过两条不同的转导途径激活保卫细胞质膜上的质子泵送，一条由蓝光感受器激活，另一条由保卫细胞叶绿体激活。这项建议的目的是详细描述泵激活过程中涉及的感觉转导步骤。利用膜片钳的电生理学技术，研究这两条通路的代谢和光生物学特性，包括ATP和其他辅因子的临界浓度、注量率依赖关系、特定的药理特性以及两条通路之间与保卫细胞对太阳辐射的反应有关的相互作用特性。蓝光感受器的特性将在低温和室温下通过光谱分析进行研究。完整叶片的气体交换技术将被用来将亚细胞和细胞水平上的可分辨特征与生理条件下的气孔表现联系起来。气孔是叶片表面的气孔，它调节水和气体进出叶片组织的通道。通过气孔的适当运输对于植物进行光合作用和维持水分平衡是至关重要的。气孔对环境刺激的反应是打开和关闭。这项研究的结果将加深我们对调节气孔运动的细胞机制的理解，更广泛地说，将增加对植物细胞中感觉转导和离子转运机制的基础知识。