• The optimal partitioning theory predicts that plants of a given species acclimate to different environments by allocating a larger proportion of biomass to the organs acquiring the most limiting resource. Are similar patterns found across species adapted to environments with contrasting levels of abiotic stress?
• We tested the optimal partitioning theory by analysing how fractional biomass allocation to leaves, stems and roots differed between woody species with different tolerances of shade and drought in plants of different age and size (seedlings to mature trees) using a global dataset including 604 species.
• No overarching biomass allocation patterns at different tolerance values across species were found. Biomass allocation varied among functional types as a result of phenological (deciduous vs evergreen broad‐leaved species) and broad phylogenetical (angiosperms vs gymnosperms) differences. Furthermore, the direction of biomass allocation responses between tolerant and intolerant species was often opposite to that predicted by the optimal partitioning theory.
• We conclude that plant functional type is the major determinant of biomass allocation in woody species. We propose that interactions between plant functional type, ontogeny and species‐specific stress tolerance adaptations allow woody species with different shade and drought tolerances to display multiple biomass partitioning strategies.

中文翻译：

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具有不同遮荫和干旱耐受力的木本物种生物量分配的全球格局：多种策略的证据

• 最佳分配理论预测给定物种的植物通过将更大比例的生物量分配给获取最大资源的器官来适应不同的环境。是否在非生物胁迫水平相反的环境中跨物种发现了类似的模式？
• 我们通过使用包括604个物种的全球数据集，通过分析不同年龄和大小的植物（幼苗到成熟树木）中具有不同遮荫和干旱耐受性的木本物种之间，如何分配生物量分配给叶，茎和根的分数生物量差异，从而测试了最佳分配理论。
• 没有发现物种间具有不同耐受性的总体生物量分配模式。由于物候（落叶与常绿阔叶树种）和广泛的系统发育（被子植物与裸子植物）差异，生物质分配在功能类型之间有所不同。此外，耐性和不耐性物种之间生物量分配响应的方向通常与最佳分配理论所预测的方向相反。
• 我们得出结论，植物功能类型是木质物种生物量分配的主要决定因素。我们建议植物功能类型，个体发育和特定物种的胁迫耐受性适应之间的相互作用允许具有不同阴影和干旱耐受性的木本植物显示多种生物量分配策略。