The Regulation of Leaf Cell Expansion by Light and Ion Flux

叶片对光的生长反应对于植物最大限度地提高其光合作用能力，同时保存有效的养分和水分是很重要的。红光和蓝光分别作用于不同的机制，通过光形态刺激叶片的生长，并通过生长细胞中发生的光合作用来促进叶片的生长。对光的生长反应与质子外流和其他穿过质膜的离子通量有关。本研究的目的是：1.表皮和叶肉细胞质膜质子泵是如何受光调节的？2.叶细胞中光诱导的离子通量是否部分由离子通道携带，如果是，光是否调节离子通道的活动？3.生长反应缺陷的突变体是否会对光表现出改变的电反应？这些问题将通过电生理学(微电极和膜片钳)技术来解决，利用拟南芥的突变体对光的生长反应发生变化。叶片生长对光的反应对于植物最大限度地进行光合作用的能力，同时保存有效的养分和水分是重要的。叶片的生长受到红光和蓝光的刺激，并通过生长细胞中发生的光合作用得到促进。对光的生长反应与穿过细胞膜的离子通量有关。这个项目将使用电学技术来研究离子通过叶细胞膜对光做出反应的机制。这项研究的结果将阐明在生长中的叶细胞的光反应中发生的初始事件。

Leaf growth responses to light are important for a plant to maximize its photosynthetic capacity while conserving available nutrients and water. Leaf growth is stimulated photo- morphogenically by red and blue light acting by separate mechanisms, and is enhanced by photosynthesis occurring in the growing cells. The growth response to light is associated with proton efflux, and other ion fluxes across the plasma membrane. The objectives of this study are to ask: 1. How is the plasma membrane proton pump regulated by light in epidermal and mesophyll cells? 2. Are light-induced ion fluxes in leaf cells carried in part by ion channels, and if so, does light regulate channel activity? 3. Will mutants defective in growth responses to light exhibit altered electrical responses to light? These questions will be approached by electrophysiological (microelectrode and patch clamp) techniques taking advantage of mutants of Arabidopsis showing altered growth responses to light. %%% Leaf growth responses to light are important for a plant to maximize its ability to carry out photosynthesis while conserving available nutrients and water. Leaf growth is stimulated by red and blue light and is enhanced by photosynthesis occurring in the growing cells. The growth response to light is associated with ion fluxes across the cell membrane. This project will use electrical techniques to study the mechanisms by which ions move across the membranes of leaf cells in response to light. The results of this research will clarify the initial events occurring in light responses of growing leaf cells.