Species-specific responses of foliar nutrients to longterm nitrogen and phosphorus additions in a lowland tropical forest
Species-specific responses of foliar nutrients to longterm nitrogen and phosphorus additions in a lowland tropical forest
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DOI：
10.1111/1365-2745.12190
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发表时间：
2014-01-01
影响因子：
5.5
通讯作者：
Turner, Benjamin L.
中科院分区：
文献类型：
--
作者：
Mayor, Jordan R.;Joseph Wright, S.;Turner, Benjamin L.
植物叶片中氮(N)和磷(P)的浓度、化学计量和吸收通常被用作这些生长限制养分有效性的代用指标，但这些指标对养分有效性变化的响应在很大程度上尚未对热带森林树木进行测试。本研究评估了巴拿马低地热带森林中4种常见树种在13年因子N和P添加后N和P浓度、N/P比率和吸收的变化。长期加磷增加了三种当地常见的苦楝树种(黑桫椤（Alseis blackiana）、黑桫椤（Heisteria coninna）和巴拿马四叶草（Tetragastris panamensis）的叶片磷浓度，降低了磷吸收能力和氮磷比。叶面磷的增加涉及两种植物有机磷和无机磷的相似比例增加，而黑木犀的无机磷增加不成比例地大。添加氮素不会改变任何物种的叶片氮浓度，但会降低水杨对氮的吸收能力。第四种棕榈（Oenocarpus mapora）表现出显著的静态叶面养分浓度，在N + P共添加的情况下，其对P的吸收能力仅略有下降。综上所述，这些结果表明，在暴露于高磷环境下的桉树中，氮磷比可以进行调整，但在这些低地雨林树种中，叶面氮似乎已经处于最佳水平。物种对营养物可用性改变的特定反应的复杂性，突出了预测热带森林树木对变化世界的未来反应的困难。
The concentration, stoichiometry and resorption of nitrogen (N) and phosphorus (P) in plant leaves are often used as proxies of the availability of these growth-limiting nutrients, but the responses of these metrics to changes in nutrient availability remain largely untested for tropical forest trees. We evaluated changes in N and P concentrations, N/P ratios and resorption for four common tree species after 13years of factorial N and P additions in a lowland tropical forest in Panama. Chronic P addition increased foliar P concentrations, decreased P resorption proficiency and decreased N/P ratios in three locally common eudicot tree species (Alseis blackiana, Heisteria concinna, Tetragastris panamensis). The increase in foliar P involved similar proportional increases in organic and inorganic P in two species and a disproportionately large increase in inorganic P in A.blackiana. Nitrogen addition did not alter foliar N concentrations in any species, but did decrease N resorption proficiency in H.concinna. A fourth species, the palm Oenocarpus mapora, demonstrated remarkably static foliar nutrient concentrations, responding only with a marginal decrease in P resorption proficiency under N plus P co-addition.Synthesis. Collectively, these results suggest that adjustment of N/P ratios can be expected in eudicots exposed to elevated P, but foliar N appears to already be at optimal levels in these lowland rain forest tree species. The complexity of species-specific responses to altered nutrient availability highlights the difficulty in predicting future responses of tropical forest trees to a changing world.