Graduate School of Life Sciences, Tohoku University, Aoba, Sendai, Japan.
Faculty of Science, Tohoku University, Aoba, Sendai, Japan.
Ann Bot. 2018 Apr 18;121(5):1055-1064. doi: 10.1093/aob/mcy001.
Models of plant three-dimensional (3-D) architecture have been used to find optimal morphological characteristics for light capture or carbon assimilation of a solitary plant. However, optimality theory is not necessarily useful to predict the advantageous strategy of an individual in dense stands, where light capture of an individual is influenced not only by its architecture but also by the architecture of its neighbours. Here, we analysed optimal and evolutionarily stable biomass allocation between the lamina and petiole (evolutionarily stable strategy; ESS) under various neighbour conditions using a 3-D simulation model based on the game theory.
We obtained 3-D information of every leaf of actual Xanthium canadense plants grown in a dense stand using a ruler and a protractor. We calculated light capture and carbon assimilation of an individual plant when it stands alone and when it is surrounded by neighbours in the stand. We considered three trade-offs in petiole length and lamina area: biomass allocation, biomechanical constraints and photosynthesis. Optimal and evolutionarily stable biomass allocation between petiole and lamina were calculated under various neighbour conditions.
Optimal petiole length varied depending on the presence of neighbours and on the architecture of neighbours. The evolutionarily stable petiole length of plants in the stand tended to be longer than the optimal length of solitary plants. The mean of evolutionarily stable petiole length in the stand was similar to the real one. Trade-offs of biomechanical constraint and photosynthesis had minor effects on optimal and evolutionarily stable petiole length.
Actual plants realize evolutionarily stable architecture in dense stands. Interestingly, there were multiple evolutionarily stable petiole lengths even in one stand, suggesting that plants with different architectures can coexist across plant communities.
植物三维（3-D）结构模型已被用于寻找单个植物的最佳形态特征，以实现对光的捕获或碳的同化。然而，最优理论不一定适用于预测密集群落中个体的有利策略，因为个体的光捕获不仅受到其自身结构的影响，还受到其邻居结构的影响。在这里，我们使用基于博弈论的 3-D 模拟模型，在各种邻体条件下，分析了叶和叶柄之间的最佳和进化稳定的生物量分配（进化稳定策略；ESS）。
我们使用尺子和量角器获得了在密集群落中生长的实际加拿大苍耳植物的每片叶子的 3-D 信息。当个体植物单独存在或处于群落中的邻居包围中时，我们计算了个体植物的光捕获和碳同化。我们考虑了叶柄长度和叶片面积的三个权衡关系：生物量分配、生物力学约束和光合作用。在各种邻体条件下，计算了叶和叶柄之间的最佳和进化稳定的生物量分配。
最优叶柄长度取决于邻体的存在和邻体的结构。群落中植物的进化稳定叶柄长度往往长于孤立植物的最优长度。群落中进化稳定叶柄长度的平均值与实际值相似。生物力学约束和光合作用的权衡关系对最优和进化稳定叶柄长度的影响较小。
实际植物在密集群落中实现了进化稳定的结构。有趣的是，即使在一个群落中，也存在多个进化稳定的叶柄长度，这表明具有不同结构的植物可以在植物群落中共同存在。
