A new model of stomatal function

植物需要将水分从土壤中吸到嫩芽中。它们通过叶片表面被称为气孔的小而可控的气孔来蒸发水蒸气。开放的气孔使植物能够在整个植物中吸收水分，同时，它们允许二氧化碳进入叶片，用于光合作用，这是我们所有食物的制造过程。然而，如果气孔总是打开，这将导致灾难性的水分流失，枯萎，并最终导致植物死亡。因此，植物不断调整它们的气孔，确保它们在条件好的时候足够开放，以便植物生长，但在有失去过多水分的危险时关闭。由于气孔在植物中的重要作用，150多年来，气孔是如何工作的一直是一个广泛研究的课题。这些工作大多集中在气孔形成的两个细胞（保护细胞）上，这导致了广泛接受的范式，即这些细胞通过获得或失去水分而膨胀和收缩，并且这种保护细胞大小和形状的变化是气孔打开和关闭的主要机制。我们最近的研究，使用三维成像，揭示了保卫细胞附近的细胞也经历了非常大的大小和形状的变化，以响应已知的关闭气孔的触发器。此外，我们的成像实验表明，保护细胞本身经历了比通常描述的更复杂的形状变化。综上所述，我们的新结果表明，经典的教科书描述并没有完全捕捉到细胞大小和形状变化导致气孔打开和关闭的机制。特别是，我们的新发现表明，保护细胞和邻近表皮细胞的反应需要一个完整和有效的气孔打开和关闭机制。这些数据不仅为植物生物学的经典和基础方面提供了新的见解，还可能为优化或改善气孔性能开辟新的途径，为减少作物需水量和提高耐旱性提供新方法，这是农业在不断变化的全球环境中面临的主要挑战。为了测试我们的想法，我们将结合先进的成像和计算建模技术，结合一系列遗传资源。例如，我们将扩展我们目前的研究，我们已经研究了两个已知的气孔关闭触发因素，看看我们观察到的保护细胞/邻近细胞反应是否反映了气孔功能的一般方面。然后，我们将使用各种方法来改变邻近细胞的活力或对气孔打开/关闭触发器的反应，测试邻近细胞功能是完整气孔功能所必需的这一想法。这些相同的方法也将用于改变我们观察到的保护细胞形状反应，测试这种特定形状变化与气孔打开和关闭机制密切相关的想法。在整个项目中，我们将创建我们正在研究的气孔系统的计算模型。这些模型将由我们的实验结果提供信息，将为该项目提供强大的理论基础，帮助我们解释我们的实验，并允许我们设计进一步的实验来测试我们关于保护细胞及其邻近细胞在气孔打开和关闭过程中共同工作的机制的想法。通过这项研究获得的对气孔力学的更好理解，可以在未来帮助生产更有弹性的作物，这些作物更适合在气候变化下生长。

Plants need to draw water up from the soil to the shoots. They do this by losing water vapour via small, controllable pores on the leaf surface, termed stomata. Open stomata allow plants to pull water throughout the plant and, at the same time, they allow carbon dioxide into the leaf where it is used for photosynthesis, the process by which all our food is made. However, if stomata were always open this would lead to catastrophic water loss, wilting, and eventual death of the plant. Therefore, plants continually adjust their stomata, making sure that they are open enough to allow the plant to grow when conditions are good, but closed when there is the danger of losing too much water. Due to their critical role in plants, how stomata work has been a topic of extensive research for over 150 years. Most of this work has focussed on the two cells (guard cells) between which the stomatal pore is formed, leading to the widely accepted paradigm that these cells swell and deflate via the gain or loss of water, and that this change of guard cell size and shape is the primary mechanism by which stomatal pores open and close. Our recent research, using 3-dimensional imaging, has revealed that cells neighbouring the guard cells also undergo very large changes in size and shape in response to triggers known to close stomata. In addition, our imaging experiments have shown that the guard cells themselves undergo a much more complicated change in shape than has generally been described. Taken together, our new results suggest that the classical text-book descriptions do not fully capture the mechanism by which changes of cell size and shape lead to stomatal opening and closing. In particular, our new findings suggest that a combination of guard cell and neighbouring epidermal cell responses is required for a full and efficient mechanism for stomatal pore opening and closure. As well as providing a new insight into a classical and fundamental aspect of plant biology, these data may open new paths to optimising or improving stomatal performance, leading to new approaches to reducing crop water requirements and improving drought tolerance, major challenges for agriculture in a changing global environment.To test our ideas, we will use a combination of advanced imaging and computational modelling techniques, combined with an array of genetic resources. For example, we will expand our present investigations where we have looked at two known triggers of stomatal closure to see whether the guard cell/neighbouring cell response that we have observed reflects a general aspect of stomatal function. We will then use a variety of approaches to alter either neighbouring cell viability or responsiveness to stomatal opening/closure triggers, testing the idea that neighbouring cell function is required for full stomatal function. These same approaches will also be used to alter the guard cell shape response that we have observed, testing the idea that this specific shape change is intimately connected with the mechanism of stomatal pore opening and closure. Throughout the project we will create computational models of the stomatal systems that we are investigating. These models, which will be informed by our experimental results, will provide a strong theoretical underpinning to the project, helping us both to interpret our experiments, and allowing us to design further experiments to test our ideas on the mechanism by which both guard cells and their neighbouring cells work together in the opening and closure of stomata.The improved understanding of stomatal mechanics gained through this research could, in the future, aid the production of more resilient crops that are better suited to growth under climate change.