Cooper L J, Daly K R, Hallett P D, Koebernick N, George T S, Roose T
Bioengineering Sciences Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, UK.
School of Biological Sciences, University of Aberdeen, Aberdeen, UK.
Proc Math Phys Eng Sci. 2018 Sep;474(2217):20180149. doi: 10.1098/rspa.2018.0149. Epub 2018 Sep 5.
Most water and nutrients essential for plant growth travel across a thin zone of soil at the interface between roots and soil, termed the rhizosphere. Chemicals exuded by plant roots can alter the fluid properties, such as viscosity, of the water phase, potentially with impacts on plant productivity and stress tolerance. In this paper, we study the effects of plant exudates on the macroscale properties of water movement in soil. Our starting point is a microscale description of two fluid flow and exudate diffusion in a periodic geometry composed from a regular repetition of a unit cell. Using multiscale homogenization theory, we derive a coupled set of equations that describe the movement of air and water, and the diffusion of plant exudates on the macroscale. These equations are parametrized by a set of cell problems that capture the flow behaviour. The mathematical steps are validated by comparing the resulting homogenized equations to the original pore scale equations, and we show that the difference between the two models is ≲7% for eight cells. The resulting equations provide a computationally efficient method to study plant-soil interactions. This will increase our ability to predict how contrasting root exudation patterns may influence crop uptake of water and nutrients.
植物生长所需的大部分水分和养分在根与土壤之间的界面处，即所谓的根际，穿过一层薄薄的土壤区域。植物根系分泌的化学物质可以改变水相的流体性质，如粘度，这可能会对植物生产力和胁迫耐受性产生影响。在本文中，我们研究了植物分泌物对土壤中水分运动宏观性质的影响。我们的出发点是对周期性几何结构中两种流体流动和分泌物扩散的微观描述，该周期性几何结构由一个单位晶胞的规则重复组成。利用多尺度均匀化理论，我们推导出了一组耦合方程，用于描述宏观尺度上空气和水的运动以及植物分泌物的扩散。这些方程由一组捕捉流动行为的单元问题进行参数化。通过将所得的均匀化方程与原始孔隙尺度方程进行比较，验证了数学步骤，并且我们表明对于八个单元，两个模型之间的差异≲7%。所得方程提供了一种计算高效的方法来研究植物 - 土壤相互作用。这将提高我们预测不同根系分泌模式如何影响作物对水分和养分吸收的能力。
