The 4-dimensional plant: enhanced mechanical canopy excitation for improved crop performance

迫切需要提高作物产量（每公顷吨数），以满足不断增长的全球人口和日益减少的肥沃农业土地基础的需要。光合作用是当前作物改良的重要目标之一，这是以前植物育种工作中被忽视的一个特性。光合作用需要叶片吸收二氧化碳，并利用水和吸收的太阳能将其转化为碳水化合物。然而，产量所依赖的高光合速率对环境变化如光照强度、温度和其他因素很敏感。作物生产力是冠层中叶片光合作用的总和，其中许多叶片相互遮蔽并且具有不同的年龄。根据叶片光合特性和其他物理生理因子，可以计算整个冠层的生产潜力。当我们这样做时，理论生产力往往比测量的生产力高得多，这部分是由于树叶在重建成一个大的三维树冠时的反应方式。在这种状态下，植物作为一个群落存在，它具有我们不一定能从单独生长的植物中预测到的涌现特性。如果我们能够消除理论生产率和实测生产率之间的差距，我们就可以实现生产率的阶跃变化。光合速率对光强敏感。存在于树冠内的光强度的差异是显著的，并且受树冠的结构（即，叶子的角度、形状和大小以及它们在三维空间内的位置）的影响。这意味着光强度在林冠内的空间和时间上有很大的变化。光合作用并不能完美地适应光照强度的波动--它的滞后会导致生产力甚至水分利用效率的大幅下降。这一提议解决了一个被忽视的因素。植物在轻到中等的风中“移动”，这每天都会发生，有时在生长过程中会持续变化，从而改变树冠内的光线模式。在最近的工作中，我们发现，运动有很大的影响，在树冠层的光水平变化的速率与冠层光合作用的强烈影响。林冠的这种运动在产生光闪烁的快慢以及它们出现在林冠的什么位置上起着重要的作用。看起来，运动可能使生产更快的“光斑”，提高光合作用在冠层水平。我们不认为高速运动会造成损害，但我们确实将倒伏纳入了冠层生存力的评估中。在最近的一篇论文中（Burgess et al（2016）Frontiers in Plant Science 7，1392）表明，冠层运动可以改变冠层水平的光合反应。我们还开发了技术，以产生高分辨率的三维图像的田间生长的小麦和水稻冠层和“跟踪”移动冠层。在本提案中，我们将把这些技术结合起来，制作水稻和小麦的冠层模型，并使这些模型能够真实地响应物理因素。与此同时，我们将使用小麦和水稻种群以及具有不同物理特性和对风的响应能力的面板，并创建这些树冠的数据驱动跟踪电影，使3D重建变得逼真。我们将创建方法来预测在这些檐篷结合光线跟踪技术与光分布的实地测量光分布。我们预测，最具生产力的属性是叶片高度响应风在冠层的顶部，但保留一个强大的僵硬stair. The同时，我们将测量光合作用和生物量生产小麦线，这是服从遗传分析，以便我们可以发现运动的遗传基础。因此，其结果将用于植物育种。

There is an urgent need to improve crop yield (tonnes per per hectare) in order to meet the needs of a growing global population and declining fertile agricultural land base. One of the current important targets for crop improvement is photosynthesis, a neglected trait in previous plant breeding efforts.Photosynthesis requires the uptake of carbon dioxide by leaves and its 'conversion' into carbohydrates using water and absorbed solar energy. However high rates of photosynthesis, on which yield depends, are sensitive to environmental changes such as light intensity, temperature and other factors. Crop productivity is the sum total of photosynthesis in leaves in a canopy, many of which shade each other and have different ages. We can calculate the potential productivity of whole canopies based on leaf photosynthetic attributes and other physical and physiological factors. When we do this the theoretical productivity tends to be much higher than the measured productivity which is partly due to the way leaves respond when re-constructed into a large three dimensional canopy. In this state, plants exist as a community which has emergent properties that we cannot necessarily predict from plants grown individually. If we can eliminate the gap between the theoretical and measured productivity we can achieve a step change in productivity. Photosynthetic rate is sensitive to light intensity. The difference in light intensities that exist within the canopy is significant and is affected by the architecture of the canopy i.e. the angle, shape and size of leaves and their position within 3 dimensional space. This means that the light intensity has great variability in space and time within canopies. Photosynthesis is not perfectly adapted to instantaneously match the fluctuations in light intensity - its lag results in substantial reductions in productivity and even water use efficiency.This proposal tackles a much ignored factor. Plants 'move' in light to moderate wind and this occurs on a daily basis, sometimes continually during growth which shifts the light patterns within the canopy. In recent work we found that movement has a strong effect on the rate at which light levels change in the canopy with strong implications for canopy photosynthesis. Such movement of the canopy plays a major part in how fast or slow light flecks are generated, and where in the canopy they appear. It seems that movement may enable the production of more rapid 'lightflecks', enhancing photosynthesis at the canopy level. We don't consider high speeds that result in damage, but we do incorporate lodging in our assessments of canopy viability.In a recent paper (Burgess et al (2016) Frontiers in Plant Science 7, 1392) showed that canopy movement has the means to alter photosynthetic responses at the canopy level. We also developed the techniques to generate high resolution 3D images of field grown wheat and rice canopies and for 'tracking' moving canopies. In this proposal we will bring these techniques together to produce models of canopies of rice and wheat and make these models move realistically in response to physical factors. At the same time we will use wheat and rice populations and panels with varied physical characteristics and responsiveness to wind and create data driven tracking movies of these canopies , making the 3D reconstruction move realistically. We will create methods for predicting light distribution in these canopies combining ray tracing techniques with field measurements of light distribution. We predict that the most productive property is for leaves to be highly responsive to wind at the top of the canopy but retaining a strong stiff stem.At the same time we will measure photosynthesis and biomass production in wheat lines which are amenable to genetic analysis so that we can discover the hereditary basis for the movement. Therefore the results will be used in plant breeding.