Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Fortaleza, Ceará, 60451-970, Brasil.
Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, Potsdam-Golm, 14476, Germany.
New Phytol. 2017 Dec;216(4):1018-1033. doi: 10.1111/nph.14823. Epub 2017 Oct 6.
Contents 1018 I. 1018 II. 1019 III. 1022 IV. 1025 V. 1026 VI. 1029 1030 References 1030 SUMMARY: Stomata are leaf epidermal structures consisting of two guard cells surrounding a pore. Changes in the aperture of this pore regulate plant water-use efficiency, defined as gain of C by photosynthesis per leaf water transpired. Stomatal aperture is actively regulated by reversible changes in guard cell osmolyte content. Despite the fact that guard cells can photosynthesize on their own, the accumulation of mesophyll-derived metabolites can seemingly act as signals which contribute to the regulation of stomatal movement. It has been shown that malate can act as a signalling molecule and a counter-ion of potassium, a well-established osmolyte that accumulates in the vacuole of guard cells during stomatal opening. By contrast, their efflux from guard cells is an important mechanism during stomatal closure. It has been hypothesized that the breakdown of starch, sucrose and lipids is an important mechanism during stomatal opening, which may be related to ATP production through glycolysis and mitochondrial metabolism, and/or accumulation of osmolytes such as sugars and malate. However, experimental evidence supporting this theory is lacking. Here we highlight the particularities of guard cell metabolism and discuss this in the context of the guard cells themselves and their interaction with the mesophyll cells.
目录 1018 I. 1018 II. 1019 III. 1022 IV. 1025 V. 1026 VI. 1029 1030 参考文献 1030 摘要：气孔是由两个保卫细胞围绕一个孔组成的叶表皮结构。这个孔的孔径变化调节植物的水分利用效率，定义为光合作用每蒸腾一片叶子的水所获得的 C。气孔孔径通过保卫细胞渗透溶质含量的可逆变化来主动调节。尽管保卫细胞可以独立进行光合作用，但似乎可以积累来自叶肉的代谢物作为信号，有助于调节气孔运动。已经表明，苹果酸可以作为一种信号分子和钾的抗衡离子，钾是一种在气孔开放时积累在保卫细胞液泡中的已确立的渗透物。相比之下，苹果酸从保卫细胞中流出是气孔关闭的一个重要机制。据推测，淀粉、蔗糖和脂质的分解是气孔开放的一个重要机制，这可能与糖酵解和线粒体代谢过程中通过 ATP 产生以及/或糖和苹果酸等渗透物的积累有关。然而，缺乏支持这一理论的实验证据。本文强调了保卫细胞代谢的特殊性，并在保卫细胞本身及其与叶肉细胞相互作用的背景下讨论了这一问题。
