Biomechanics of plant growth
Biomechanics of plant growth
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DOI：
10.3732/ajb.93.10.1415
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发表时间：
2006-10-01
影响因子：
3
通讯作者：
Schopfer, Peter
中科院分区：
文献类型：
--
作者：
Schopfer, Peter
膨胀细胞的生长被定义为细胞体积和表面积的不可逆增加，可以被认为是由细胞壁的机械性质和原生质体的渗透性质控制的物理过程。不可逆的细胞膨胀是通过细胞壁中的应力松弛减少膨压而产生吸水的驱动力而产生的。因此，这种机械-液压过程取决于壁的机械性能并可由壁的机械性能控制，而壁的机械性能又受到壁松弛和壁硬化反应的影响。这些机械壁特性变化的生化机制及其通过内部信号（例如，激素）或外部信号（例如，光、干旱胁迫）目前尚未完全理解，并进行深入研究。这些信号作用于具有复合材料性质的壁，其中聚合物的分子结构和空间组织而不是机械应力的分布决定了细胞和器官生长的异速生长，从而决定了细胞和器官的形状。细胞壁结构对异速生长的重要性可以通过用微管干扰药物如秋水仙碱干扰壁聚合物的定向沉积来证明。延长器官（例如，圆柱形茎或胚芽鞘）表现出纵向组织张力，导致壁应力从控制器官生长的内细胞层转移到外周细胞层。对于物理分析导致种子发芽的生长过程，与正常生长相同的机械和水力参数原则上是合适的。然而，为了涵盖抑制胚扩展的组织（种皮、胚乳）的影响，必须考虑附加力和透水性项。
Growth of turgid cells, defined as an irreversible increase in cell volume and surface area, can be regarded as a physical process governed by the mechanical properties of the cell wall and the osmotic properties of the protoplast. Irreversible cell expansion is produced by creating a driving force for water uptake by decreasing the turgor through stress relaxation in the cell wall. This mechano-hydraulic process thus depends on and can be controlled by the mechanical properties of the wall, which in turn are subject to modification by wall loosening and wall stiffening reactions. The biochemical mechanisms of these changes in mechanical wall properties and their regulation by internal signals (e.g., hormones) or external signals (e.g., light, drought stress) are at present incompletely understood and subject to intensive research. These signals act on walls that have the properties of composite materials in which the molecular structure and spatial organization of polymers rather than the distribution of mechanical stresses dictate the allometry of cell and organ growth and thus cell and organ shape. The significance of cell wall architecture for allometric growth can be demonstrated by disturbing the oriented deposition of wall polymers with microtubuleinterfering drugs such as colchicine. Elongating organs (e.g., cylindrical stems or coleoptiles) composed of different tissues with different mechanical properties exhibit longitudinal tissue tensions resulting in the transfer of wall stress from inner to peripheral cell layers that adopt control over organ growth. For physically analyzing the growth process leading to seed germination, the same mechanical and hydraulic parameters as in normal growth are principally appropriate. However, for covering the influences of the tissues that restrain embryo expansion (seed coat, endosperm), an additional force and a water permeability term must be considered.