Biophysics of Development of the Plant Shoot

植物芽发育的生物物理学

• 批准号: 8801493
• 负责人: Paul Green
• 金额: $ 66.74万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-06-01 至 1993-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8801493&HistoricalAwards=false
• 关键词: Biophysics; Development; Plant; Shoot

Multicellular development in plants involves a long causal chain between genome and macroscopic phenotype. Cell behavior is a key intermediate stage. One the one hand the genome provides the basis for the cell behavior. On the other, the cell behavior, when integrated through time and space, produces the successive developmental stages. Dr. Green specialize in these later aspects of the causal chain. Dr. Green studies the development of the shoot in terms of the directional reinforcement, by cellulose, in the walls of growing cells. Cells maintain, or reorient, the direction of cellulose synthesis at mitosis. A biophysical theory to explain the origin and spacing of leaves, phyllotaxis, is being developed. Its main tenet is that growth of recently formed leaves influences the apical dome by stretching its cells which then establish new reinforcement patterns on the dome. This can explain the placement of subsequent leaves. Now he proposes to test experimentally the apparent key relationship- between cell stretch and reinforcement behavior by altering organ stretch patterns and studying cell responses. He also proposes to find out if the present theory can be extended to additional phyllotactic patterns and if it can be applied to the generation of form in leaves. Sufficiency of the biophysical explanations will be tested by a finite element program which correlates physical forces and cell responses in model meristems. A general biophysical theory for shoot development should result. %%% Research in this project centers on the way that plants inherit their geometrical features. The best known examples of pattern in plant shoots are the spiral lines seen in the heads of sunflowers and the helical lines made by the scales on a pine cone. These spiral patterns are also found in the leaf patterns of most plants growing in temperate zones. Obviously, plants have a "developmental engine" that produces leaves in a pattern specific to the plant. The present research is concerned with the cellular basis of the formation of these patterns. The patterns are generated by a cycle of activity at the stem tip. At the stem tip, leaves or other appendages, arise at points of discontinuity in the reinforcements patterns around cell surfaces. These reinforcement patterns are a result of cellulose microfibrils. Once a leaf is establishes, the growth of its base act of the adjacent tissue, stretching it. This causes a response in neighboring cells which create new discontinuities. Thus surface irregularities lead to organs and the organs make irregularities. The cycle can go on to perpetuate a fixed pattern. This research is to expand this interpretation of all patterns and to examine the apparently key connection between physical stretch and the cell response which alters reinforcement direction.

植物的多细胞发育涉及基因组和宏观表型之间的长因果链。 细胞行为是关键的中间阶段。 一方面，基因组为细胞行为提供了基础。 另一方面，细胞行为通过时间和空间整合时，产生连续的发育阶段。 格林博士专注于因果链的这些后续方面。 格林博士通过纤维素对生长细胞壁的定向强化来研究芽的发育。 细胞在有丝分裂时维持或重新定向纤维素合成的方向。 一种解释叶子起源和间距的生物物理学理论——叶序——正在发展中。 其主要原理是，新形成的叶子的生长通过拉伸其细胞来影响顶端圆顶，然后在圆顶上建立新的加固模式。 这可以解释后续叶子的位置。 现在，他提议通过改变器官拉伸模式和研究细胞反应来通过实验测试细胞拉伸和强化行为之间明显的关键关系。 他还建议找出当前的理论是否可以扩展到其他叶序模式，以及是否可以应用于叶子形式的生成。 生物物理解释的充分性将通过有限元程序进行测试，该程序将模型分生组织中的物理力和细胞反应相关联。 应该得出芽发育的一般生物物理理论。 %%% 该项目的研究重点是植物继承其几何特征的方式。植物芽中最著名的图案例子是向日葵头部的螺旋线和松果上的鳞片形成的螺旋线。这些螺旋图案也存在于温带地区生长的大多数植物的叶子图案中。 显然，植物有一个“发育引擎”，可以按照植物特有的模式产生叶子。目前的研究涉及这些模式形成的细胞基础。这些图案是由茎尖的活动循环产生的。在茎尖、叶子或其他附属物处，出现在细胞表面周围的强化图案的不连续点处。这些增强图案是纤维素微纤维的结果。 一旦叶子长成，其基部的生长就会作用于邻近的组织，将其拉伸。这会引起相邻小区的响应，从而产生新的不连续性。 因此，表面的不规则性导致器官的不规则性，而器官则产生不规则性。这个循环可以继续下去，以维持固定的模式。这项研究旨在扩展对所有模式的这种解释，并检查物理拉伸和改变强化方向的细胞反应之间明显的关键联系。