Computational modeling of cellular morphogenesis and shape functionality in plants

植物的发育和功能由组成有机体的组织和细胞的形状和分化决定。与动物细胞不同，植物细胞被一种坚硬的基质--细胞壁所包围。因此，细胞发育过程，如细胞尺寸的增加和细胞形状的改变，需要这种聚合物壁的机械变形。反过来，细胞壁的机械特性决定了分化细胞的几何形状。人们一直致力于整体细胞形状的变化，例如在圆柱形茎或根细胞伸长过程中发生的变化。然而，我们对控制复杂细胞几何形状的产生的力学原理知之甚少，例如星形毛状体或拼图形状的叶表皮细胞。传统的数值模拟方法无法应对这种复杂程度，我建议使用为机械工程应用开发的分析工具，结合一系列定量实验方法，对决定植物细胞生长的机械过程进行建模，并确定细胞形状如何影响细胞功能。这项研究计划将细胞生物学方法与微机械工程和计算模拟相结合，作为模型系统，我们将研究一种生长速度极快的一维细胞--花粉管，以及叶表皮二维扩张的铺面细胞。我们将使用力学测试和显微研究相结合的方法来检查细胞的几何形状和生长行为。我们将使用细胞力学技术量化生物物理细胞参数，并使用有限元方法将这些数据整合到理论模型中。这一研究项目是高度跨学科的，因为它将各种细胞生物学方法(分子生物学、高端激光扫描显微镜、电子显微镜)与微机械工程和计算建模相结合，并为生物学和数学/工程学这两个学科的研究生提供机会。

Plant development and functioning are determined by the shape and differentiation of the tissues and cells composing the organism. Unlike animal cells, plant cells are surrounded by a stiff matrix, the cell wall. Consequently, cell developmental processes such as increase in cell size and change in cell shape require the mechanical deformation of this polymer wall. In turn, the mechanical properties of the cell wall determine the geometry of the differentiating cell. Much attention has been devoted to overall cell shape changes such as those occurring during the elongation of cylindrical stem or root cells. However, we have a poor understanding of the mechanical principles that govern the generation of complex cellular geometries such as those of star-shaped trichomes or jigsaw puzzle shaped leaf epidermis cells. Conventional numerical modeling methods are unable to cope with this degree of complexity and I propose to use analytic tools developed for applications in mechanical engineering, in combination with an array of quantitative experimental approaches, to model the mechanical processes that determine plant cell growth and to determine how cell shape influences cell function. This research program combines cell biological approaches with micromechanical engineering and computational modeling.As model systems we will study an extremely fast and one-dimensionally growing cell, the pollen tube, and the two-dimensionally expanding pavement cells of the leaf epidermis. We will use mechanical testing in combination with microscopic investigation to examine cellular geometry and growth behavior. We will quantify biophysical cellular parameters using cytomechanical techniques, and we will integrate these data into a theoretical model using finite element methods. This research program is highly interdisciplinary as it combines various cell biological approaches (molecular biology, high end confocal laser scanning microscopy, electron microscopy) with micromechanical engineering and computational modeling and it offers opportunities for graduate students from both disciplines: biology and mathematics/engineering.