Contrasting species responses to continued nitrogen and phosphorus addition in tropical montane forest tree seedlings
Contrasting species responses to continued nitrogen and phosphorus addition in tropical montane forest tree seedlings
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DOI：
10.1111/btp.12518
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发表时间：
2018-03-01
期刊：
影响因子：
2.1
通讯作者：
Homeier, Juergen
中科院分区：
文献类型：
--
作者：
Carate-Tandalla, Daisy;Camenzind, Tessa;Homeier, Juergen
全球养分沉积速率的变化可能对植物群落产生深远的影响，特别是在热带养分有限的系统中。我们研究了增加养分供应量的影响，在厄瓜多尔南部的山地森林中的6个树种的幼苗原位。经过五年的持续N，P，或N+P添加，自然生长的幼苗的每两个最常见的物种在每个海拔（1000，2000，3000米asl）收获叶形态，营养成分，植食性和组织生物量分配的分析。大多数物种表现出增加叶面N和P浓度后，每个相应的元素。所有物种的对照植物的叶组织N：P比>20，表明在这些森林中P比N更限制生长。叶形态的养分添加反应的物种和养分特异性，与一些物种（紫花草，Graffenrieda embryata）表现出比叶面积（SLA）增加，和其他（Graffenrieda harlingii）增加叶面积比（LAR）。1000m的Pouteriatorta在施磷后SLA和LAR降低。草食性增加仅在G.（N和N+P添加后）。只有3000m海拔的物种在营养盐添加后改变了生物量分配。在一般情况下，N和N+P除了更强烈地影响了在高海拔地区研究的物种，而P除了在所有海拔地区对物种的影响范围相似。我们的结论是，所研究的热带山地森林树种幼苗慢性N和P的反应是高度物种特异性的，成功适应增加养分供应将取决于物种特异性的形态和生理可塑性。
Global changes in nutrient deposition rates are likely to have profound effects on plant communities, particularly in the nutrient-limited systems of the tropics. We studied the effects of increased nutrient availability on the seedlings of six tree species in montane forests of southern Ecuador insitu. After five years of continued N, P, or N+P addition, naturally grown seedlings of each of the two most common species at each elevation (1000, 2000, and 3000m asl) were harvested for analyses of leaf morphology, nutrient content, herbivory, and tissue biomass allocation. Most species showed increased foliar N and P concentrations after addition of each respective element. Leaf tissue N:P ratios of >20 in the control plants of all species suggest that P is more growth-limiting in these forests than N. Leaf morphological responses to nutrient addition were species and nutrient specific, with some species (Hedyosmum purparescens, Graffenrieda emarginata) exhibiting increased specific leaf area (SLA), and others (Graffenrieda harlingii) increased leaf area ratios (LAR). Pouteria torta (1000m) had lower SLA and LAR after P addition. Increased herbivory was only evident in G. emarginata (after N and N+P addition). Only the species from 3000m asl modified biomass allocation after nutrient addition. In general, N and N+P addition more strongly affected the species studied at the upper elevations, whereas P addition had a similar range of effects on the species at all elevations. We conclude that the responses of the studied tropical montane forest tree seedlings to chronic N and P addition are highly species-specific and that successful adaptation to increased nutrient availability will depend on species-specific morphological and physiological plasticity.