SOIL COMPACTION AND PLANT-ROOT GROWTH
SOIL COMPACTION AND PLANT-ROOT GROWTH
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DOI：
10.1098/rstb.1990.0175
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发表时间：
1990-09-29
影响因子：
6.3
通讯作者：
HETTIARATCHI, DRP
中科院分区：
文献类型：
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作者：
HETTIARATCHI, DRP
当土壤孔隙空间不能容纳根系伸展时，植物根系受到机械阻抗的影响。本文简要地考察了应力和水分历史在改变根系生长可用的孔隙空间和限制根系变形土壤能力的土壤强度方面的综合影响的理论方面。描述了一种根扩展模型，该模型需要根顶几何形状的循环变化来克服孔隙空间限制。根生长区内的细胞被分析为简单几何形状的受压薄壁结构，由对称的不可伸展的原纤维网络增强的聚合弹性体组成。这种结构表现出一些意想不到的但独特的形状变化，由纤维排列和作用于外表面的接触应力共同控制。根尖的简化模型可以从这些结构单元中构建出来，该模型的行为支持了提出的由根穿透致密土壤演变而来的可变根尖几何规律。该分析强调了物理因素在根系生长过程中所起的关键作用，所描述的不同模型为根系增殖的综合定量模型的发展提供了基础。
Plant roots are subjected to mechanical impedance when soil pore space cannot accommodate the extending root system. The paper examines briefly the theoretical aspects of the combined effects of stress and moisture history in modifying both the pore space available for root growth and soil strength that limits the ability of roots to deform the soil. A root extension model that requires cyclic changes in root apex geometry to overcome pore space confinement is described. Cells in the growth zone of roots are analyzed as pressurized thin-walled structures of simple geometrical shape made of a polymeric elastomer reinforced by a network of symmetrical inextensible fibrils. Such structures exhibit somewhat unexpected but unique changes in shape governed by both fibril arrangement and contact stresses acting on the external surfaces. A simplified mode of a root apex can be constructed from these structural units and the behaviour of this model lends support to the proposed variable root apex geometry routine evolved by roots to penetrate compact soils. This analysis highlights the crucial role played by physical factors in the growth processes of roots and the disparate models described provide the basis for the development of a comprehensive quantitative model of root proliferation.