Georg-August-Universität Göttingen, Göttingen, Germany.
IRHS, INRAE, Institut Agro Rennes-Angers, Université d'Angers, SFR 4207 QUASAV, Beaucouzé, France.
Methods Mol Biol. 2024;2722:35-49. doi: 10.1007/978-1-0716-3477-6_3.
Depending on the questions to be answered, water flow in the xylem can be modelled following different approaches with varying spatial and temporal resolution. When focussing on the influence of hydraulic architecture upon flow dynamics, distribution of water potentials in a tree crown or questions of vulnerability of the hydraulic system, functional-structural plant models, which link representations of morphological structure with simulated processes and with a virtual environment, can be a promising tool. Such a model will then include a network of idealized xylem segments, each representing the conducting part of a stem or branch segment, and a numerical machinery suitable for solving a system of differential equations on it reflecting the hydrodynamic laws, which are the basis of the broadly accepted cohesion-tension theory of water flow in plants. We will discuss functional-structural plant models, the simplifications that are useful for hydraulic simulations within this framework, the deduction of the used differential equations from basic physical conservation laws, and their numerical solution, as well as additional necessary models of radiation, photosynthesis, and stomatal conductance. In some supplementary notes, we are shortly addressing some related questions, for example, about root systems or about the relation between macro-scale hydraulic parameters and fine-grained (anatomical) xylem structure.
根据要回答的问题，木质部中的水流可以通过不同的方法进行建模，具有不同的空间和时间分辨率。当关注水力结构对流动动态的影响、树冠中的水分势分布或水力系统的脆弱性问题时，将形态结构表示与模拟过程以及虚拟环境联系起来的功能结构植物模型可能是一种很有前途的工具。这样的模型将包括一个理想化的木质部段网络，每个段代表一个茎或分支段的传导部分，以及一个适合于求解反映水动力规律的微分方程组的数值机制，这些规律是被广泛接受的植物中水分流动的内聚张力理论的基础。我们将讨论功能结构植物模型，在这个框架内进行水力模拟有用的简化，从基本物理守恒定律推导出所使用的微分方程，以及它们的数值解，以及辐射、光合作用和气孔导度的其他必要模型。在一些补充说明中，我们简要地讨论了一些相关的问题，例如，关于根系或关于宏观水力参数与细粒度（解剖学）木质部结构之间的关系。
