Lacointe André, Minchin Peter E H
Université Clermont Auvergne, INRA, PIAF, Clermont-Ferrand, France.
New Zealand Institute for Plant and Food Research, Motueka Research Centre, Motueka, New Zealand.
Methods Mol Biol. 2019;2014:371-386. doi: 10.1007/978-1-4939-9562-2_28.
Modeling is a fundamental part of quantitative science used to bring together several quantitative components, often developed though detailed reductionist approach on component parts, e.g., sucrose transport through a membrane osmotic relation. It is now generally accepted that phloem transport is the result of bulk solution flow generated by the difference in osmotic pressure between source and sink tissues. However, there is still little agreement on how different sink tissues compete for available carbohydrate. Furthermore, the impact of phloem pathway leakage (unloading) and reloading on source-to-sink carbon transport remains unclear. Moreover, it is debated to what degree the interactions between phloem and xylem flows influence carbohydrate source-sink relations. These aspects are extremely difficult to research by a reductionist approach, with modeling being an important tool to examine the consequences of proposed mechanisms, which can then be tested on whole plants.Phloem/xylem modeling has been at the limits of quantitative modeling, especially when dynamic models are needed to explain tracer studies. Advances in computing now enable more realistic modeling, which are utilized by the PiafMunch approach described here. This model enables a high level of mechanistic detail to be incorporated and the observable effect of it to be tested. In the most recent version of the software with the introduction of tracer dynamics, it can now predict the effects of specific phloem mechanisms upon the shape of evolving tracer profiles.
建模是定量科学的一个基本组成部分，用于整合多个定量要素，这些要素通常是通过对组成部分进行详细的还原论方法来开发的，例如蔗糖通过膜渗透关系的运输。现在人们普遍认为，韧皮部运输是源组织和库组织之间渗透压差异产生的大量溶液流动的结果。然而，对于不同的库组织如何竞争可用碳水化合物，仍然存在很少的共识。此外，韧皮部途径渗漏（卸载）和再装载对源到库碳运输的影响仍不清楚。此外，韧皮部和木质部流动之间的相互作用在多大程度上影响碳水化合物源库关系也存在争议。这些方面用还原论方法极难研究，建模是检验所提出机制后果的重要工具，然后可以在整株植物上进行测试。韧皮部/木质部建模一直处于定量建模的极限，尤其是在需要动态模型来解释示踪剂研究时。现在计算技术的进步使得更现实的建模成为可能，本文所述的PiafMunch方法就利用了这一点。该模型能够纳入高水平的机制细节并测试其可观察到的效果。在软件的最新版本中引入了示踪剂动力学，现在它可以预测特定韧皮部机制对不断演变的示踪剂分布形状的影响。
