Gayler S, Grams T E E, Heller W, Treutter D, Priesack E
Institute of Soil Ecology, GSF-National Research Center for Environment and Health, D-85764 Neuherberg, Germany.
Ann Bot. 2008 May;101(8):1089-98. doi: 10.1093/aob/mcm169. Epub 2007 Aug 10.
Patterns and variations in concentration of carbon-based secondary compounds in plant tissues have been explained by means of different complementary and, in some cases, contradictory plant defence hypotheses for more than 20 years. These hypotheses are conceptual models which consider environmental impacts on plant internal demands. In the present study, a mathematical model is presented, which converts and integrates the concepts of the 'Growth-Differentiation Balance' hypothesis and the 'Protein Competition' model into a dynamic plant growth model, that was tested with concentration data of polyphenols in leaves of juvenile apple, beech and spruce trees. The modelling approach is part of the plant growth model PLATHO that considers simultaneously different environmental impacts on the most important physiological processes of plants.
The modelling approach for plant internal resource allocation is based on a priority scheme assuming that growth processes have priority over allocation to secondary compounds and that growth-related metabolism is more strongly affected by nitrogen deficiency than defence-related secondary metabolism.
It is shown that the model can reproduce the effect of nitrogen fertilization on allocation patterns in apple trees and the effects of elevated CO(2) and competition in juvenile beech and spruce trees. The analysis of model behaviour reveals that large fluctuations in plant internal availability of carbon and nitrogen are possible within a single vegetation period. Furthermore, the model displays a non-linear allocation behaviour to carbon-based secondary compounds.
The simulation results corroborate the underlying assumptions of the presented modelling approach for resource partitioning between growth-related primary metabolism and defence-related secondary metabolism. Thus, the dynamical modelling approach, which considers variable source and sink strengths of plant internal resources within different phenological growth stages, presents a successful translation of existing concepts into a dynamic mathematical model.
二十多年来，植物组织中碳基次生化合物浓度的模式及变化一直通过不同的互补性（在某些情况下相互矛盾）的植物防御假说进行解释。这些假说是考虑环境对植物内部需求影响的概念模型。在本研究中，提出了一个数学模型，该模型将“生长 - 分化平衡”假说和“蛋白质竞争”模型的概念转化并整合为一个动态植物生长模型，并用幼年苹果树、山毛榉树和云杉树叶中多酚浓度数据对其进行了测试。该建模方法是植物生长模型PLATHO的一部分，PLATHO同时考虑了不同环境对植物最重要生理过程的影响。
植物内部资源分配的建模方法基于一种优先级方案，该方案假设生长过程优先于次生化合物的分配，并且与生长相关的代谢比与防御相关的次生代谢受氮缺乏的影响更大。
结果表明，该模型能够再现氮肥对苹果树分配模式的影响，以及二氧化碳浓度升高和竞争对幼年山毛榉树和云杉树的影响。对模型行为的分析表明，在单个植被期内，植物内部碳和氮的可利用性可能会有大幅波动。此外，该模型对碳基次生化合物表现出非线性分配行为。
模拟结果证实了所提出的用于生长相关初级代谢和防御相关次生代谢之间资源分配建模方法的基本假设。因此，该动态建模方法考虑了不同物候生长阶段植物内部资源可变的源库强度，成功地将现有概念转化为了一个动态数学模型。
