摘要
Aims The scaling relationship between nitrogen(N)and phosphorus(P)concentrations([N]and[P],respectively)in leaves manifests plants’relative investment between the two nutrients.However,the variation in this relationship among taxa as well as its causes was seldom described.Methods The analysis was based on a dataset including 2483 leaf samples from 46 genera of angiosperm woody plants from 1733 sites across China.We calculated the leaf N–P scaling exponent(βL)with an allometric equation([N]=α[P]β),for each genus,respectively.We then performed phylogenetic path analyses to test how the climate and soil niche conditions of these genera contributed to the inter-genus variation inβL.Important Findings The genera living with lower soil P availability presented a more favoured P uptake relative to N,as shown by the higherβL,suggesting a resistant trend to P limitation.Additionally,genus-wiseβL was positively correlated with soil N–P scaling exponents(β_(S)),implying that the variation in leaf nutrients is constrained by the variability in their sources from soil.Finally,climatic factors including temperature and moisture did not affectβL directly,but could have an indirect influence by mediating soil nutrients.Phylogeny did not affect the inter-genus variation inβL along environmental gradients.These results reveal that the trade-off between N and P uptake is remarkably shaped by genus niches,especially soil nutrient conditions,suggesting that theβL could be considered as a functional trait reflecting characteristics of nutrient utilization of plant taxa in response to niche differentiation.
植物叶片中氮(N)、磷(P)含量的异速生长关系表明了植物对这两种元素的相对投入。而,现有的研究很少关注这一关系在分类单元之间的差异及其成因。本研究基于来自全国1733个样地,属于46个木本被子植物属的2483个叶片样品,利用异速生长方程([N]=α[P]β)分别计算了各属的叶氮、磷含量异速生长指数(β_(L))。然后利用谱系路径分析检验了这些属的气候和土壤生态位条件如何影响属间的β_(L)的差异。生活在贫磷土壤中的属更可能表现出更高的β_(L),即相对于氮而言更强的磷积累,这可能表明了植物对磷限制的抵抗倾向。此外,各属的β_(L)与相对应的土壤氮、磷含量异速生长指数(β_(S))正相关,这可能表明了叶养分的变化受制于作为来源的土壤养分的变化。最后,包括温度和湿度在内的气候因子不会直接影响β_(L)的属间变化,但可能通过调节土壤养分水平发挥间接的作用。谱系关系不会影响各属β_(L)随环境梯度的变化。这些结果揭示了植物对氮、磷摄取的权衡关系可能受属生态位,特别是土壤生态位的影响,表明了β_(L)可以作为一项反映植物养分利用特征如何响应生态位差异的功能属性。
基金
This work was funded by the National Natural Science Foundation of China(32025025,31988102 and 31770489)
the Strategic Priority Research Programme of the Chinese Academy of Sciences(XDAO5O5OOOO).
