Optimization modeling of plant root architecture for water and phosphorus acquisition
Optimization modeling of plant root architecture for water and phosphorus acquisition
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DOI：
10.1016/j.jtbi.2003.09.011
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发表时间：
2004-02-07
影响因子：
2
通讯作者：
Lynch, JP
中科院分区：
文献类型：
--
作者：
Ho, MD;McCannon, BC;Lynch, JP
提出了一个优化模型，该模型考察了空间异质性环境中的多种资源获取，特别是水和磷的获取与根构型之间的关系。以菜豆单株的基根生长角作为决策变量进行建模，该角度决定了菜豆根系整体的方向和定位。植物的总收益，即从获取水分和磷中获得的收益，减去根系之间的空间竞争成本，是二维笛卡尔空间中基根的(x，y)坐标的函数。我们得到了一个通解，并将其应用于四种独特的环境情况：(1)均匀分布的水和磷的情况；(2)局部浅水磷的情况；(3)局部深水的情况；(4)浅水和深水的情况。一般解指出，最优的基根生长角将出现在所获得的资源价值的总变化率等于将根定位在土壤更深处所产生的总成本变化率的点上。优化植物的根在土壤剖面中定位得更深，直到边际收益恰好等于边际成本。该模型预测，相对于均匀分布水分和磷的情况，优化植株的根角在情况2下较浅，在情况3下较深。情况4的最佳基本根角将取决于随深度发生的水有效性对磷有效性的边际替代率。温室和田间对豆根构型的经验观察证实了模型的结果，并对此进行了讨论。此外，还讨论了表型可塑性和表型变异在优化性状和适应空间异质性环境方面的潜在重要性。(C)2003年，爱思唯尔有限公司出版。
An optimization model is presented that examines the relationship between root architecture and multiple resource acquisition, specifically water and phosphorus in spatially heterogeneous environments. The basal root growth angle of an individual common bean plant, which determines the orientation and localization of the bulk of the root system, was modeled as the decision variable. The total payoff to the plant, the benefit obtained from water and phosphorus acquisition, minus the costs of spatial competition between roots, is given as a function of the (x,y) coordinates of the basal root in two-dimensional Cartesian space. We obtained a general solution and applied it to four unique environmental cases which are as follows: (1) the case of uniformly distributed water and phosphorus; (2) the case of localized shallow phosphorus; (3) the case of localized deep water; and (4) the case of shallow phosphorus and deep water. The general solution states that the optimal basal root growth angle will occur at the point where the total rate of change in the value of the resources acquired equals the total rate of change in cost that results from locating the root deeper in the soil. An optimizing plant locates its roots deeper in the soil profile until the marginal benefit exactly equals the marginal cost. The model predicts that the basal root angle of an optimizing plant will be shallower for Case 2 and deeper for Case 3, relative to the basal root angle obtained in the case of uniformly distributed water and phosphorus. The optimal basal root angle for Case 4 will depend on the marginal rate of substitution of water availability for phosphorus availability that occurs with depth. Empirical observations of bean root architecture in the greenhouse and in the field confirm model results and are discussed. In addition, the potential importance of phenotypic plasticity and phenotypic variation are discussed in relation to optimization of traits and adaptation to spatially heterogeneous environments. (C) 2003 Published by Elsevier Ltd.