School of Forestry and Environmental Studies, Yale University, 195 Prospect Street, New Haven, CT, 06511, USA.
National Institute for Mathematical and Biological Synthesis, University of Tennessee, 1122 Volunteer Blvd, Ste. 106, Knoxville, TN, 37996, USA.
New Phytol. 2014 Sep;203(4):1119-1127. doi: 10.1111/nph.12864. Epub 2014 May 29.
The relationship between branch diameter and leaf size has been widely used to understand how vegetative resources are allocated in plants. Branching architecture influences reproductive allocation as well, but fewer studies have explored this relationship at broad phylogenetic or ecological scales. In this study, we tested whether pollen-producing and seed-producing cone size scales with branch diameter in conifers, a diverse and globally distributed lineage of nonflowering seed plants. Branch diameter and cone size were analyzed using multiple regression models and evolutionary models of trait evolution for a data set of 293 extant conifer species within an explicit phylogenetic framework. Branch diameter is a strong predictor of cone size across conifer species, particularly for pollen cones and dry seed cones. However, these relationships are complex in detail because leaf morphology and seed dispersal biology influence the specific ways in which they are expressed. The ubiquity and strength of these scaling relationships across conifers suggest that reproductive and vegetative morphologies are coupled in the group, and it is therefore difficult to disentangle the evolution of cone size from the evolution of branching architecture.
分支直径与叶片大小之间的关系已被广泛用于了解植物中营养物质资源的分配方式。分支结构对生殖分配也有影响，但很少有研究在广泛的系统发育或生态尺度上探索这种关系。在这项研究中，我们测试了针叶树中花粉产生和种子产生的球果大小是否与分支直径有关，针叶树是一种多样化且分布广泛的非开花种子植物谱系。在明确的系统发育框架内，使用多元回归模型和性状进化的进化模型分析了 293 种现存针叶树种的数据集中的分支直径和球果大小。分支直径是针叶树种中球果大小的一个强有力的预测因子，尤其是对于花粉球果和干种子球果。然而，这些关系在细节上很复杂，因为叶片形态和种子传播生物学影响了它们表达的具体方式。这些在针叶树中普遍存在且强大的比例关系表明，生殖和营养形态在该组中是耦合的，因此很难将球果大小的进化与分支结构的进化区分开来。
