Controlled buckling as a mechanism to regulate cuticle patterning in plants

植物的外表面覆盖着一层薄薄的防水材料，称为角质层。当空气干燥时，角质层保护植物免于脱水，并且它还保护植物的脆弱组织免受昆虫和其他动物的损害以及细菌和真菌等病原体的入侵。有一个角质层是绝对必要的所有植物在陆地上的生存，角质层的进化是一个关键步骤，当植物生命第一次搬到陆地上，已经开始在海洋中。我们感兴趣的是，我们发现在植物角质层表面的图案。这些图案由表皮材料中的脊、皱纹或波浪形成。它们可以随机出现，也可以遵循非常有组织的安排，如一组长线或星星形状。它们也可能不存在，给一个完全光滑的角质层。所有这些不同的角质层模式都会影响植物与周围世界相互作用的方式，这取决于模式的类型和它形成的器官。例如，花瓣角质层上的长脊，如果以规则的方式组织，可以干扰到达植物表面的光并产生彩虹色效果。这些对花很重要，可以吸引传粉者。一个不同的例子是在一些叶子上发现的较大规模的脊，这使得叶子表面光滑，昆虫用脚上的粘性垫抓地力。因此，这些植物受到保护，免受一些甲虫，否则会吃他们。角质层图案也会影响植物表面的润湿性，其中一种最不湿润的植物--圣莲，为涂料和其他表面涂层的设计提供了灵感，（被广泛称为“莲花效应”）。没有人知道这些不同的图案是如何在植物表面形成的，但我们的初步数据表明，它们是由植物细胞生长时表皮材料的弯曲产生的。我们已经建立了一个模型，表明屈曲力的产生是因为植物细胞在一个方向上比另一个方向生长得更多，这会拉伸和压缩顶部的角质层。我们的模型表明，只有当角质层具有正确的刚度时，才会发生屈曲，这将是角质层详细化学成分的结果。该模型表明，我们可以将植物表面的图案看作是植物细胞及其角质层的自然属性的结果-如果细胞生长，角质层化学和角质层生产以特定的方式结合在一起，那么就会发生屈曲并形成图案。在本提案中，我们希望测试我们的模型，以详细了解角质层图案是如何形成的。我们相信这种理解在很多方面都很重要，为生产具有不同作用的人造表面提供灵感，提出通过操纵植物与环境的相互作用来提高作物产量的方法，甚至为生物多样性和保护工作提供投入。通过更详细地解释植物如何与环境相互作用。为了测试我们的模型，我们将使用一系列不同的方法来改变或干扰植物细胞的生长，产生的角质层的数量以及角质层的化学性质。然后，我们将分析这些变化如何影响角质层屈曲和图案形成。我们的许多方法将依赖于改变控制细胞生长和角质层产生或化学的基因的活性，但我们也将使用植物组织的物理拉伸和细胞生长的药理学（化学）破坏来提供各种不同的角质层模式。我们的数据将反馈到我们的模型中，并提供对这一重要生物过程的深刻理解。

The outer surfaces of plants are covered in a thin layer of a water-repellent material called the cuticle. The cuticle protects the plant from dehydration when the air is dry, and it also protects the plant's delicate tissues from damage by insects and other animals and from invasion by pathogens such as bacteria and fungi. Having a cuticle is absolutely essential for the survival of all plants on land, and the evolution of the cuticle was a key step when plant life first moved onto the land, having begun in the sea.We are interested in the patterns that we find on the surface of plant cuticles. These patterns are formed from ridges, wrinkles or waves in the cuticular material. They can appear random, or can follow very organised arrangements such as sets of long lines or star shapes. They may also be absent, giving an entirely smooth cuticle. All of these different cuticle patterns affect the way that the plant interacts with the world around it, depending on the type of pattern and the organ on which it forms. For example, long ridges on the petal cuticle, if organised in a regular way, can interfere with light arriving at the plant surface and produce iridescent effects. These can be important on flowers to attract pollinators. A different example is the larger scale ridges found on some leaves, which make the leaf surface slippery for insects that grip with adhesive pads on their feet. As a result, these plants are protected from some of the beetles that would otherwise eat them. Cuticle patterns can also affect the wettability of the plant surface, and one of the least wettable plants, the Sacred Lotus, has provided the inspiration for the design of paints and other surface coatings that shed water (widely known as the "Lotus effect").Nobody knows how these different patterns form on the plant surface, but our preliminary data suggest that they are produced by buckling of the cuticular material as the plant cells grow. We have developed a model which suggests that buckling forces arise because the plant cells grow more in one direction than another, and this stretches and compresses the cuticle on top. Our model suggests that buckling can only occur if the cuticle is of the right stiffness, which will be a result of the detailed chemical make-up of the cuticle. The model suggests that we can think of the patterns on the plant surface as a result of the emergent properties of the plant cells and their cuticle - if cell growth, cuticle chemistry and cuticle production come together in a specific way, then buckling will occur and patterns will be formed.In this proposal we would like to test our model, to gain a detailed understanding of how cuticle patterns form. We believe that this understanding will be important in a range of ways, providing inspiration for the production of artificial surfaces with different roles, suggesting ways of improving crop yield by manipulating the plant's interaction with the environment, and even providing input into biodiversity and conservation work by explaining how plants interact with their environments in more detail. To test our model we will use a range of different approaches to change or perturb the growth of plant cells, the amount of cuticle produced, and the chemistry of cuticle. We will then analyse how these changes influence cuticle buckling and pattern formation. Many of our approaches will rely on altering the activity of the genes controlling cell growth and cuticle production or chemistry, but we will also use physical stretching of plant tissues and pharmacological (chemical) disruption of cell growth to give a wide range of different cuticle patterns. Our data will feed back into our model and provide a strong understanding of this important biological process.