Plant traits and species interactions along gradients of N:P:K stoichiometry

沿 N:P:K 化学计量梯度的植物性状和物种相互作用

• 批准号: 289574330
• 负责人: Dr. Vanessa Minden
• 金额: --
• 依托单位: Arbeitsgruppe Landschaftsökologie
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/289574330?language=en
• 关键词: Plant; traits; species; interactions; along

Nutrient enrichment, as a consequence of fertilization, atmospheric deposition and modification of landscape has changed the relative importance of nutrient elements in limiting productivity, with many formerly phosphorus (P) limited aquatic systems being today nitrogen (N) limited and many terrestrial systems showing patterns of P limitation. Ecological consequences of higher nutrient input rates are shifts in ratios of nutrients and higher productivity rates, loss of species and increase in number of endangered species. It has been shown that different species are adapted to different types of nutrient limitation. As a response to nutrient limitation, plants show distinct traits, e.g. N limitation is associated with a higher root length, whereas P limitation induces higher root phosphatase activity. An important field of research in this context is ecological stoichiometry (ES) theory, which describes the balance of elements and energy in biological functions and processes. ES studies have mainly focused on N and P, but another macronutrient of similar importance, potassium (K), has received less attention. K is the second most abundant nutrient in leaves after nitrogen, and by that more abundant than phosphorus. Even though the total soil K pools are generally higher than those of N and P, soil-plant available K concentrations are often lower, also, organic matter in soils contains almost no K. Current studies indicate that reduction in soil K availability is related to N deposition, which makes K more sensitive to changes in land use and fertilization than either N or P. There are only few studies on the response of plants to different supply rates of N, P and K, although evidence supports that K is already a limiting nutrient in terrestrial ecosystems.A lot of research has been done on the effects of N and P on plant growth and competition. However, studies on the role of K in direct comparison to N and P are still missing. With this fellowship I aim at conducting research on the role of elemental nutrients on the growth patterns of plant species. I will conduct a greenhouse experiment with the focus on competitive interactions between species adapted to different types of nutrient limitation along gradients of N, P and K availability. Secondly, I will work on existing data sets collected by the Landscape Ecology Group of the Univ. of Oldenburg, with data on 110 species (from salt marsh ecosystems, reeds, grasslands, semi-dry grassland, heathlands and ruderal habitats), element concentrations (N, P, K) of all tissue types (leaves, stems, roots), as well as biomass allocation traits, Specific Leaf Area, canopy height and ecosystem properties (e.g. productivity, decomposition). Plant available N, P and K concentrations of the soil are available, which allows the direct relation of elemental tissue concentration with elemental resource concentration within the various ecosystems and along gradients from wet habitats to dry habitats.

由于施肥、大气沉降和景观改变而导致的营养物富集改变了营养元素在限制生产力方面的相对重要性，许多以前磷（P）有限的水生系统现在是氮（N）有限的，许多陆地系统显示出磷限制的模式。较高的养分投入率的生态后果是养分比例的变化和较高的生产率，物种的损失和濒危物种数量的增加。已经表明，不同的物种适应不同类型的营养限制。作为对养分限制的响应，植物表现出不同的性状，例如，N限制与更高的根长相关，而P限制诱导更高的根磷酸酶活性。在这方面的一个重要研究领域是生态化学计量学（ES）理论，它描述了生物功能和过程中元素和能量的平衡。ES研究主要集中在N和P上，但另一种具有类似重要性的常量营养素钾（K）受到的关注较少。钾是叶片中含量仅次于氮的第二丰富的营养素，比磷更丰富。尽管土壤钾素总库一般高于氮、磷库，但土壤-植物有效钾含量往往较低，土壤有机质中几乎不含钾。目前的研究表明，土壤钾有效性的降低与氮沉降有关，这使得钾比氮或磷对土地利用和施肥的变化更敏感。尽管有证据表明钾已经是陆地生态系统中的限制性营养素，但已经对氮和磷对陆地生态系统的影响进行了大量的研究。植物生长与竞争然而，在直接比较N和P的K的作用的研究仍然缺失。通过这项研究金，我的目标是研究元素营养素对植物物种生长模式的作用。我将进行一个温室实验，重点是适应不同类型的养分限制的物种之间的竞争相互作用沿着梯度的N，P和K的可用性。其次，我将研究奥尔登堡大学景观生态学小组收集的现有数据集，其中包括110个物种的数据（来自盐沼生态系统、芦苇、草地、半干旱草地、石楠和杂草生境）、所有组织类型的元素浓度（N、P、K）（叶、茎、根）以及生物量分配特征、比叶面积、冠层高度和生态系统特性（例如生产力、分解）。土壤的植物有效N、P和K浓度是可用的，这使得元素组织浓度与各种生态系统内以及从湿生境到干生境的沿着梯度上的元素资源浓度直接相关。