State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; CAS Research Center for Ecology and Environment of Central Asia, Urumqi 830011, China.
School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China.
Sci Total Environ. 2020 Aug 10;729:138920. doi: 10.1016/j.scitotenv.2020.138920. Epub 2020 Apr 23.
Nutrient resorption from senescent leaves is one essential plant nutrient strategy. Allocation of nitrogen (N) and phosphorus (P) reflects the influences of evolution and ecological processes on plant functional traits, and thus is related to functional types and environmental factors. However, we know little about the pattern among plant functional types (PFTs) and the driving factors of the allometric relationship of N resorption efficiency (NRE) against P resorption efficiency (PRE) in plant leaves (NRE ~ PRE; b, scaling exponent). We compiled N and P resorption data from the literature, including 2541 records, 894 plant species, and 488 sites worldwide, and then explored the allometric relationships between NRE and PRE across different PFTs and environmental factors (i.e. climate and soil nutrients). The scaling exponent for overall species was 0.88, suggesting that plants generally re-absorb P from senesced leaves at a higher rate than N. Among diverse PFTs, the scaling exponents of broadleaved (0.91), deciduous (0.92), non-leguminous (0.88), and woody plants (0.90) were higher than those of coniferous (0.81), evergreen (0.89), leguminous (0.74), and herbaceous plants (0.76), respectively. The scaling exponents increased with increasing latitude and soil nutrient (N and P) availability, and decreased with increasing mean annual temperature. Our results suggest that terrestrial plants utilize P relative to N more effectively through resorbing a higher proportion of P than N from senescent leaves. However, the differential resorption efficiency between N and P may vary among diverse plant types, and displayed a biogeographic pattern at global scale through the plant-environment interactions. These findings can broaden our understanding of the nutrient recycling processes within plants, and help in better prediction of nutrient balance in response to global changes.
从衰老叶片中回收养分是植物重要的养分获取策略之一。氮（N）和磷（P）的分配反映了进化和生态过程对植物功能性状的影响，因此与功能类型和环境因素有关。然而，我们对植物功能类型（PFTs）之间的模式以及植物叶片中氮回收效率（NRE）与磷回收效率（PRE）之间的比例关系（NRE ~ PRE；b，标度指数）的驱动因素知之甚少。我们从文献中汇编了 N 和 P 回收数据，包括 2541 条记录、894 个植物物种和全球 488 个地点，然后探索了不同 PFTs 和环境因素（即气候和土壤养分）下 NRE 和 PRE 之间的比例关系。总体物种的标度指数为 0.88，表明植物通常从衰老的叶片中以更高的速率回收 P 而不是 N。在不同的 PFTs 中，阔叶植物（0.91）、落叶植物（0.92）、非豆科植物（0.88）和木本植物（0.90）的标度指数高于针叶植物（0.81）、常绿植物（0.89）、豆科植物（0.74）和草本植物（0.76）。标度指数随着纬度和土壤养分（N 和 P）可用性的增加而增加，随着年平均温度的升高而降低。我们的结果表明，陆地植物通过从衰老的叶片中回收比 N 更高比例的 P 来更有效地利用 P 相对于 N。然而，N 和 P 之间的差异回收效率可能因不同的植物类型而异，并通过植物-环境相互作用在全球范围内呈现出生物地理格局。这些发现可以拓宽我们对植物内部养分循环过程的理解，并有助于更好地预测全球变化下的养分平衡。
