Optimising Photosynthetic Efficiency via Leaf Structure

几乎我们所有的食物最终都依赖于光合作用的过程，通过光合作用，大气中的二氧化碳利用阳光的能量被固定成单糖。这一过程主要发生在植物的叶片中。虽然光合作用的生物化学过程是高度保守的（即，不同植物的叶片形状非常相似），不同物种之间甚至同一物种内的叶片形状都非常多变，这取决于环境条件。叶片的形状对光合作用很重要，因为它将直接影响光合作用的效率。例如，大气中的二氧化碳必须首先通过叶片表面的小孔（气孔）进入叶片，然后通过空气空间穿过叶片内部，然后到达叶绿体所在的细胞，这是光合作用发生的地方。尽管这些距离看起来很小，但二氧化碳运动的内部途径的差异会对光合作用的效率产生重大影响。该项目的目的是了解更多关于光合作用效率和叶片内部细胞结构之间联系的规则。通过对这些规律的进一步了解，我们将更有能力选择能够更有效地进行光合作用的新植物品种。为了实现这一目标，我们将首先使用模式植物拟南芥。这是最先进的实验室植物，我们已经开发了工具，使我们能够操纵这种叶子的细胞结构是一种精确和可控的方式。因此，我们将产生具有各种改变的细胞结构的植物。然后，我们将分析这些架构使用先进的成像技术，称为微型计算机断层扫描。这将为我们提供有关可能影响树叶内二氧化碳流动的许多参数的定量数据。我们还将分析相同的叶子，以研究它们进行光合作用的情况。通过结合这些数据，我们将能够，首先，测试已经提出的关于细胞结构对光合作用效率的重要性的想法。我们还将能够分析我们的数据，以寻找新的架构，这些架构可以提高光合作用的效率，但不会对叶子产生不利的连锁影响，例如对水分流失率的影响。这种对细胞结构、光合作用和生理学的协调有序的分析将有助于确定与这些因素相关的基本规则。最后，通过与菲律宾国际水稻研究所（IRRI）的同事联系，（一个主要的水稻研究中心，世界上最重要的农作物）我们将研究从我们实验室工厂获得的数据是否有助于筛选实验，这些实验正在进行，以尝试和鉴定改良的水稻品种。

Almost all our food depends eventually on the process of photosynthesis by which carbon dioxide in the atmosphere is fixed, using the energy of sunlight, into simple sugars. This process occurs mainly in the leaves of plants. Although the biochemical process of photosynthesis is highly conserved (i.e., is very similar in different plants), leaf form is very variable, both between different species and even within a species, depending on environmental conditions.The form of the leaf is important for photosynthesis since it will directly influence the efficiency of the process. For example, carbon dioxide in the atmosphere must first enter aleaf by small pores on the leaf surface (stomata), then traverse the inside of the leaf via air spaces before reaching the cells where the chloroplasts are located, which is where photosynthesis occurs. Even though these distances may seem quite small, differences in this internal pathway of carbon dioxide movement can have a major affect on the efficiency of photosynthesis. The aim of this project is to understand more about the rules which link the efficiency of photosynthesis and the internal cellular architecture of a leaf. By knowing more about these rules, we will be in a stronger position to select new breeds of plant which can perform photosynthesis more efficiently.To achieve this aim, we will initially use the model plant Arabidopsis. This is the most advanced lab plant and we have developed tools which allow us to manipulate the cellular architecture of this leaf is a precise and controlled fashion. We will thus generate plants with a variety of altered cellular architectures. We will then analyse these architectures using an advanced imaging technique called micro-computer tomography. This will provide us with quantitative data on a number of parameters which might influence the flow of carbon dioxide within a leaf. We will also analyse the same leaves to investigate how well they are performing photosynthesis. By combining these data, we will be able, firstly, to test ideas already put forward on the importance of cellular architecture for the efficiency of photosynthesis. We will also be able to analyse our data to look for novel architectures which could act to improve the efficiency of photosynthesis but which do not have adverse knock-on affects for the leaf, for example on the rate of water loss. This concerted and ordered analysis of cellular architecture and photosynthesis and physiology will help identify the ground rules relating these factors.Finally, by linking up with colleagues working at the International Rice Research Institute (IRRI) in the Phillipines (a main centre for rice research, the most important crop in the world) we will investigate whether the data obtained from our lab plant can help in screening experiments which are being performed to try and identify improved rice varieties.