BACKGROUND AND AIMS Intraspecific variation in foundation species of forest ecosystems can shape community and ecosystem properties, particularly when that variation has a genetic basis. Traits mediating interactions with other species are predicted by simple allocation models to follow ontogenetic patterns that are rarely studied in trees. The aim of this research was to identify the roles of genotype, ontogeny and genotypic trade-offs shaping growth, defence, and reproduction in aspen. METHODS We established a common garden replicating over 500 aspen genets in Wisconsin, USA. Trees were measured through the juvenile period into the onset of reproduction, for growth, defence chemistry (phenolic glycosides, condensed tannins), nitrogen, extrafloral nectaries, leaf morphology (specific leaf area), flower production, and foliar herbivory and disease. We also assayed the TOZ19 sex marker and heterozygosity at 10 microsatellite loci. KEY RESULTS We found high levels of genotypic variation for all traits, and high heritabilities for both the traits and their ontogenetic trajectories. Ontogeny strongly shaped intraspecific variation, and trade-offs among growth, defence, and reproduction supported some predictions while contradicting others. Both direct resistance (chemical defence) and indirect defence (extrafloral nectaries) declined during the juvenile stage, prior to the onset of reproduction. Reproduction was higher in trees that were larger, male, and had higher individual heterozygosity. Growth was diminished by genotypic allocation to both direct and indirect defence as well as to reproduction, but we found no evidence of trade-offs between defence and reproduction. CONCLUSIONS Key traits affecting the ecological communities of aspen have high levels of genotypic variation and heritability, strong patterns of ontogeny, and clear trade-offs among growth, defence, and reproduction. The architecture of aspen's community genetics-its ontogeny, trade-offs and especially its great variability-is shaped by both its broad range and diverse community of associates and in turn further fosters that diversity.

中文翻译：

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白杨的成长：个体发育和权衡塑造了基础物种的生长、防御和繁殖


背景和目的 森林生态系统基础物种的种内变异可以塑造群落和生态系统特性，特别是当这种变异具有遗传基础时。通过简单的分配模型来预测介导与其他物种相互作用的特征，以遵循很少在树木中研究的个体发育模式。本研究的目的是确定基因型、个体发育和基因型权衡对白杨生长、防御和繁殖的作用。方法 我们在美国威斯康星州建立了一个公共花园，复制了 500 多个白杨基因。对树木从幼年期到繁殖开始、生长、防御化学（酚苷、缩合单宁）、氮、花外蜜腺、叶子形态（特定叶面积）、花卉产量以及叶食草和疾病进行测量。我们还测定了 10 个微卫星位点的 TOZ19 性别标记和杂合性。主要结果 我们发现所有性状都存在高水平的基因型变异，并且这些性状及其个体发育轨迹都具有高遗传力。个体发育强烈地塑造了种内变异，生长、防御和繁殖之间的权衡支持了一些预测，同时又与其他预测相矛盾。在繁殖开始之前的幼年阶段，直接抵抗力（化学防御）和间接防御（花外蜜腺）均下降。较大、雄性且个体杂合性较高的树木的繁殖率较高。生长因直接和间接防御以及繁殖的基因型分配而减弱，但我们没有发现防御和繁殖之间权衡的证据。 结论影响白杨生态群落的关键性状具有高水平的基因型变异和遗传力、强烈的个体发育模式以及生长、防御和繁殖之间的明确权衡。白杨的群落遗传学的结构——它的个体发育、权衡，特别是它的巨大变异性——是由其广泛而多样化的同事社区塑造的，反过来又进一步促进了这种多样性。