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1.
温带湿地植物生物量分配格局调控群落水平养分回收效率对氮磷添加的响应
养分回收是植物养分利用策略的一个重要组成部分,但养分有效性的变化如何调控群落尺度上植物养分回收过程仍不清楚。在本研究中,我们提出两个科学问题:(1)叶片和茎养分回收过程对养分有效性增加的响应格局是不是一致?(2)群落尺度上养分富集引起的植物养分回收变化是受物种内养分回收可塑性的影响还是受物种组成变化的调控?本研究以中国东北草本植物占优势的温带湿地为研究对象,利用施肥实验调查了氮和磷添加3年后物种水平上植物地上部分生物量以及叶和茎养分回收的变化趋势,并评价了群落尺度上植物养分回收对3年养分添加的响应。对于植物叶和茎而言,氮和磷添加对养分回收效率(nutrient resorption efficiency)均没有影响,但降低了相应的养分回收度(nutrient resorption proficiency)。同样地,在群落水平上,植物氮和磷养分回收度也随着相应的养分添加而降低。而且,由于植物群落组成变化及其引起的叶茎比降低,氮添加显著降低群落尺度上植物氮和磷的养分回收效率。这些研究结果表明,温带湿地植物叶和茎养分回收过程对养分有效性增加的响应是一致的,而且养分富集引起的物种组成以及叶和茎生物量分配格局变化是驱动群落尺度上植物养分回收动态的重要因素。 相似文献
2.
Jacob E. Allgeier Amy D. Rosemond 《Journal of experimental marine biology and ecology》2011,407(2):330-336
The traditional model of nutrient availability in coastal estuarine ecosystems is based on predictable inputs of nitrogen (N) and phosphorus (P) via riverine and oceanic sources, respectively. But coastlines with low nutrient input from these sources may not fit into this simple framework. Here we use observational (seagrass nutrient content) and experimental (nutrient enrichment assays) data for assessing nutrient availability and limitation for primary producers along a spatial transect extending from the mouth (nearest to the ocean) to the terminal portion (boundary with the terrestrial ecosystem) of three coastal mangrove-lined tidal creeks in The Bahamas. Compiling seagrass nutrient content from all sites showed a negative relationship between seagrass nutrient limitation (either N or P) and distance from mouth, but this pattern differed across sites with respect to which nutrient was more limiting. Our experimental results demonstrated patterns of decreased response by microalgae to dual nutrient enrichment in one site with distance from the creek mouth, and increased response to single nutrient enrichment in another, with the third showing no trend along this gradient. Our findings show that Bahamian mangrove wetlands are extremely nutrient-limited ecosystems, and that the most limiting nutrient varied among sites. In general, these ecosystems deviate from the typical paradigm of spatial nutrient limitation patterns in estuaries. We suggest that various site-specific biological and physical factors may be more important than large-scale hydrologic factors in driving trends of nutrient availability in coastal ecosystems under strong nutrient constraints, such as in The Bahamas. Our findings suggest that even minor changes in nutrient loading rates can have significant implications for primary production in subtropical oligotrophic systems. 相似文献
3.
Plant roots exude numerous metabolites into the soil that influence nutrient availability. Although root exudate composition is hypothesized to be under selection in low fertility soils, few studies have tested this hypothesis in a phylogenetic framework. In this study, we examined root exudates of three pairs of Helianthus species chosen as phylogenetically-independent contrasts with respect to native soil nutrient availability. Under controlled environmental conditions, seedlings were grown to the three-leaf-pair stage, then transferred to either high or low nutrient treatments. After five days of nutrient treatments, we used gas chromatography-mass spectrometry for analysis of root exudates, and detected 37 metabolites across species. When compared in the high nutrient treatment, species native to low nutrient soils exhibited overall higher exudation than their sister species native to high nutrient soils in all three species pairs, providing support for repeated evolutionary shifts in response to native soil fertility. Species native to low nutrient soils and those native to high nutrient soils responded similarly to low nutrient treatments with increased exudation of organic acids (fumaric, citric, malic acids) and glucose, potentially as a mechanism to enhance nutrition acquisition. However, species native to low nutrient soils also responded to low nutrient treatments with a larger decrease in exudation of amino acids than species native to high nutrient soils in all three species pairs. This indicates that species native to low nutrient soils have evolved a unique sensitivity to changes in nutrient availability for some, but not all, root exudates. Overall, these repeated evolutionary divergences between species native to low nutrient soils and those native to high nutrient soils provide evidence for the adaptive value of root exudation, and its plasticity, in contrasting soil environments. 相似文献
4.
Foliar nutrient resorption patterns of four functional plants along a precipitation gradient on the Tibetan Changtang Plateau 总被引:1,自引:0,他引:1
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Guangshuai Zhao Peili Shi Jianshuang Wu Dingpeng Xiong Ning Zong Xianzhou Zhang 《Ecology and evolution》2017,7(18):7201-7212
Nutrient resorption from senesced leaves as a nutrient conservation strategy is important for plants to adapt to nutrient deficiency, particularly in alpine and arid environment. However, the leaf nutrient resorption patterns of different functional plants across environmental gradient remain unclear. In this study, we conducted a transect survey of 12 communities to address foliar nitrogen (N) and phosphorus (P) resorption strategies of four functional groups along an eastward increasing precipitation gradient in northern Tibetan Changtang Plateau. Soil nutrient availability, leaf nutrient concentration, and N:P ratio in green leaves ([N:P]g) were linearly correlated with precipitation. Nitrogen resorption efficiency decreased, whereas phosphorus resorption efficiency except for sedge increased with increasing precipitation, indicating a greater nutrient conservation in nutrient‐poor environment. The surveyed alpine plants except for legume had obviously higher N and P resorption efficiencies than the world mean levels. Legumes had higher N concentrations in green and senesced leaves, but lowest resorption efficiency than nonlegumes. Sedge species had much lower P concentration in senesced leaves but highest P resorption efficiency, suggesting highly competitive P conservation. Leaf nutrient resorption efficiencies of N and P were largely controlled by soil and plant nutrient, and indirectly regulated by precipitation. Nutrient resorption efficiencies were more determined by soil nutrient availability, while resorption proficiencies were more controlled by leaf nutrient and N:P of green leaves. Overall, our results suggest strong internal nutrient cycling through foliar nutrient resorption in the alpine nutrient‐poor ecosystems on the Plateau. The patterns of soil nutrient availability and resorption also imply a transit from more N limitation in the west to a more P limitation in the east Changtang. Our findings offer insights into understanding nutrient conservation strategy in the precipitation and its derived soil nutrient availability gradient. 相似文献
5.
How substrate affects periphyton biomass and nutrient state at different, but high, nutrient levels was tested in three large enclosures in a hypereutrophic subtropical shallow lake. We compared periphytic characteristics (1) on three hard substrates (stone, bamboo, and wood) incubated for 2 weeks and 1 year, respectively, to investigate the existence of the influences of substrate type at hypereutrophic levels, and (2) on artificial plants with contrasting (parvopotamid-like and myriophyllid-like) soft substrate morphology. In general, periphytic biomass and nutrient state were sensitive to variations in nutrient level, incubation time, hard substrate type (except 2-week incubated) and substrate morphology, but to a varying extent. The periphyton nutrient content increased with increasing nutrient levels on most substrates. Long-time incubated substrates supported more periphytic biomass, had a higher nutrient content and autotrophic proportion, while the effect of nutrient level on nutrient content in the periphyton was independent of incubation time. The effects of hard substrate type on periphyton characteristics were much weaker than those of nutrient level. By contrast, the effects of soft substrate morphology on periphyton biomass and carbon: nutrient ratios surpassed those of nutrient level. Chlorophyll a, dry mass, and ash free dry mass were much higher on parvopotamid than on myriophyllid substrates. Our results show that periphyton biomass and nutrient state are influenced by both substrate and nutrient level even in hypereutrophic lakes, which might have cascading effects on the benthic food web. 相似文献
6.
关于植物营养生态学 总被引:7,自引:0,他引:7
植物营养学与植物生态学发展的前沿交叉正形成了植物营养生态学,植物营养生态学是探讨植物营养利用策略的科学,包括植物体内营养的合理利用策略和植物对无机营养环境的改造以利于营养吸收的各种可能策略。其研究内容主要包括养分利用效率、植物体内营养的再利用、体内营养含量格局和植物对土壤无机营养环境的改造。植物营养生态学以植物种群为研究对象。它的发展对深刻理解种群的生态行为特征具有重要意义,同时对如何增进人工混交群落的营养协调性具有实践上的指导意义。营养生态机理的各个方面是相互协调和相互补充的整体,营养生态机理的效率决定了种群营养合理利用的程度和在营养资源上的竞争力。目前,研究上尚缺少营养策略与其它生态策略的关联性的探讨,随着各种营养策略研究上的深入,这种关联性探讨将成为今后植物营养生态学的主要发展趋势。 相似文献
7.
Anthropogenic nutrient inputs into native ecosystems cause fluctuations in resources that normally limit plant growth, which has important consequences for associated food webs. Such inputs from agricultural and urban habitats into nearby natural systems are increasing globally and can be highly variable, spanning the range from sporadic to continuous. Despite the global increase in anthropogenically-derived nutrient inputs into native ecosystems, the consequences of variation in subsidy duration on native plants and their associated food webs are poorly known. Specifically, while some studies have examined the effects of nutrient subsidies on native ecosystems for a single year (a nutrient pulse), repeated introductions of nutrients across multiple years (a nutrient press) better reflect the persistent nature of anthropogenic nutrient enrichment. We therefore contrasted the effects of a one-year nutrient pulse with a four-year nutrient press on arthropod consumers in two salt marshes. Salt marshes represent an ideal system to address the differential impacts of nutrient pulses and presses on ecosystem and community dynamics because human development and other anthropogenic activities lead to recurrent introductions of nutrients into these natural systems. We found that plant biomass and %N as well as arthropod density fell after the nutrient pulse ended but remained elevated throughout the nutrient press. Notably, higher trophic levels responded more strongly than lower trophic levels to fertilization, and the predator/prey ratio increased each year of the nutrient press, demonstrating that food web responses to anthropogenic nutrient enrichment can take years to fully manifest themselves. Vegetation at the two marshes also exhibited an apparent tradeoff between increasing %N and biomass in response to fertilization. Our research emphasizes the need for long-term, spatially diverse studies of nutrient enrichment in order to understand how variation in the duration of anthropogenic nutrient subsidies affects native ecosystems. 相似文献
8.
Aims
Given the importance of resorption in nutrient conservations, nutrient resorption should change with leaf age if resorption depends on nutrient content, and if nutrient content changes with leaf age. However, no study has addressed this issue. 相似文献
9.
González AL Fariña JM Pinto R Pérez C Weathers KC Armesto JJ Marquet PA 《Oecologia》2011,167(3):835-845
Carbon, nitrogen, and phosphorus (C, N, P) stoichiometry influences the growth of plants and nutrient cycling within ecosystems.
Indeed, elemental ratios are used as an index for functional differences between plants and their responses to natural or
anthropogenic variations in nutrient supply. We investigated the variation in growth and elemental content of the rootless
terrestrial bromeliad Tillandsia landbeckii, which obtains its moisture, and likely its nutrients, from coastal fogs in the Atacama Desert. We assessed (1) how fog nutrient
supply influences plant growth and stoichiometry and (2) the response of plant growth and stoichiometry to variations in nutrient
supply by using reciprocal transplants. We hypothesized that T. landbeckii should exhibit physiological and biochemical plastic responses commensurate with nutrient supply from atmospheric deposition.
In the case of the Atacama Desert, nutrient supply from fog is variable over space and time, which suggests a relatively high
variation in the growth and elemental content of atmospheric bromeliads. We found that the nutrient content of T. landbeckii showed high spatio-temporal variability, driven partially by fog nutrient deposition but also by plant growth rates. Reciprocal
transplant experiments showed that transplanted individuals converged to similar nutrient content, growth rates, and leaf
production of resident plants at each site, reflecting local nutrient availability. Although plant nutrient content did not
exactly match the relative supply of N and P, our results suggest that atmospheric nutrient supply is a dominant driver of
plant growth and stoichiometry. In fact, our results indicate that N uptake by T. landbeckii plants depends more on N supplied by fog, whereas P uptake is mainly regulated by within-plant nutrient demand for growth.
Overall, these findings indicate that variation in fog nutrient supply exerts a strong control over growth and nutrient dynamics
of atmospheric plants, which are ubiquitous across fog-dominated ecosystems. 相似文献
10.
植物根毛的发生、发育及养分吸收 总被引:2,自引:0,他引:2
根毛是植物吸收养分的重要器官,认识根毛的发生、发育规律及其与养分吸收的关系,可为植物养分吸收效率的遗传改良提供依据。介绍了植物根毛的形态特性、发生和发育过程及其调控机制,并结合本实验室的工作,讨论了根毛对养分吸收的贡献、根毛受养分有效性的调节及其与其他根系形态构型性状间的关系,阐述了根毛中养分转运等植物营养过程及其生理和分子生物学基础。最后提出了关于根毛研究中的一些问题和研究前景。 相似文献
11.
12.
Two contrasting strategies of plants from disturbed areas are reported to depend on nutrient availability. Resprouters, investing into storage and capable of vegetative regeneration after disturbance, are predicted to be enhanced in nutrient poor environments. This contrasts to seeders, which invest preferentially into seed production and regenerating only from seeds, and are thought to prevail in nutrient rich environments. To test such predicted dichotomy, we set up an experiment with two facultative resprouters with contrasting nutrient demands and assessed the fitness of individuals regenerated from seeds and root fragments in differently productive environments. We hypothesized that 1) plants with higher nutrient demands have a higher fitness as seeders irrespectable of nutrient availability and/or 2) both species will have a higher fitness as resprouters under lower nutrient availability and as seeders when nutrient availability is higher. Nutrient availability was also manipulated prior to and after disturbance to evaluate the impact of changing nutrient availability on the strategy of resprouting. The results of our pot experiment with Plantago lanceolata and Plantago media supported the first but not the second hypothesis. Moreover, high nutrient availability prior to disturbance negatively affected resprouting success, but the growth and fitness of successfully regenerated individuals were enhanced under higher nutrient availability. We concluded that resprouting from roots after disturbance is affected by nutrient availability, but this effect considerably differs between individual life-history stages. 相似文献
13.
14.
Nutrient content of Abutilon theophrasti seeds and the competitive ability of the resulting plants 总被引:3,自引:0,他引:3
Summary Siblings of Abutilon theophrasti, were grown on a nutrient gradient. The plants grown at higher nutrient levels were larger and produced larger and more seeds than plants grown at lower soil nutrient concentrations. There were no differences in germinability of seeds, but the competitive abilities of resulting plants were markedly different.In two different competition experiments designed to eliminate the effects of genotype, seed size, and germination time, by using synchronously germinated seedlings derived from similar size seed from plants grown at different nutrient levels, we found that plants from seeds produced at higher nutrient levels consistently, outperformed plants from seeds produced at the lower nutrient levels. The dominance of seeds produced at higher nutrient levels may be explained by the fact that they had markedly higher concentrations of nitrogen than did seeds produced at lower soil nutrient levels. The additional advantage of increased seed quality to plants controlling more of the nutrient resource than their neighbors would be expected to accelerate their contributions to the gene pool of the population. 相似文献
15.
Although the flowering of facultative biennials is size-dependent, flowering size varies markedly within a single population as well as among populations. In this study, 15 half-sib families of the facultative biennial Aster kantoensis were grown from seeds at three nutrient levels (low, medium, and high). A significant nutrient × family interaction effect was found for bolting size, and among-family variation in bolting size increased with decreasing nutrient level. Growth from bolting to flowering tended to be greatest at the high nutrient level. Such responses of bolting size and growth from bolting to flowering resulted in an increase in flowering size at the high nutrient level and a significant variation in its reaction norm among families. For flowering age, there was a significant interaction of nutrient × family, and its among-family variation increased with decreasing nutrient levels, as was the case with bolting size. These results indicate that genetic variation in phenotypic plasticity of bolting size with nutrient availability was one cause of the variation in flowering size and age in the A. kantoensis population on the floodplain with the spatially heterogeneous nutrient availability. Moreover, responses of growth from bolting to flowering to nutrient availability could enhance the variation in flowering size. 相似文献
16.
R. Milla P. Castro-Díez M. Maestro-Martínez G. Montserrat-Martí 《Plant and Soil》2005,266(1-2):303-313
To reveal the environmental and substrate quality effects on decomposition process and enzyme activities, litterbag experiments
containing Nuphar and Carex leaves, Nuphar rhizome, and Ranunculus shoot, were carried in five-subalpine marshes in Lake Tahoe basin, USA. Alkaline phosphatase, β-glucosidase, and β-xylosidase activities were determined by a fluorogenic method using methyumbelliferyl substrates. Carex leaves, Nuphar rhizome and leaves, and Ranunculus shoots lost, respectively, 33, 67, 82 and 93% of original dry weight over 268 days. Decay rates were different among substrates
but not among marshes. Nitrogen and carbon contents increased during the first 58 days and subsequently remained stable. Phosphorus
content was stable during the experimental period except for a decrease in the first 16 days in Nuphar shoots. Enzyme activities in decomposing Carex and Nuphar leaves in four marshes were not significantly affected by environmental conditions. β-glucosidase and β-xylosidase activities in decomposing Carex leaves increased with time, but in other plant tissue these enzyme activities remained stable during experimental period.
Enzyme activities were significantly different among decomposing substrates. Alkaline phosphatase activity was highest in
Nuphar leaves (ca. 1286 μ-mole h−1 g DW −1) but lower and similar in other plant tissues (ca. 100 and 10 μ-mole h −1 g DW −1, respectively). This study showed differences in decay rates and enzyme activities rely on substrate and not the environment
conditions of the study area. Decomposition rates in the early stage of decomposition were related to cumulative enzyme activities. 相似文献
17.
Nutrient-uptake and nutrient-use efficiency ofPinus thunbergii Parl. along a topographical gradient of soil nutrient availability 总被引:2,自引:0,他引:2
To examine responses of a plant species to nutrient availability, we investigated changes in soil nutrient availability, litterfall
production and nutrient content in litterfall along a topographic gradient in aPinus thunbergii Parl. plantation. Responses were evaluated in terms of three efficiency indices: (i) nutrient-uptake efficiency (the ratio
of nutrient return in litterfall to soil nutrient availability); (ii) nutrient-use efficiency (the ratio of litterfall mass
to nutrient return in litterfall); and (iii) nutrient-response efficiency (the ratio of litterfall mass to soil nutrient availability).
These indices can distinguish the ability of a species to acquire nutrients and its ability to use them in litterfall production.
Nitrogen and phosphorus availabilities in soil were lower in upper slope positions. The three efficiencies were higher in
upper slope positions and negatively correlated with soil nutrient availability for both nitrogen and phosphorus. An increase
in nutrient-response efficiency was achieved by both increases in nutrient-uptake and nutrient-use efficiencies. 相似文献
18.
Trait values and not invasive status determine competitive outcomes between native and invasive species under varying soil nutrient availability
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Invasion by exotic plants is often associated with nutrient enrichment of soils, particularly on soils of naturally low fertility. As a consequence, it is likely that the outcome of competitive interactions between native and invasive plants may be mediated by soil nutrient availability. We independently investigated competitive effect and response as well as the occurrence of asymmetric competition among native and invasive plants on soils of varying nutrient availability, using a glasshouse experiment. Seedlings of eight co‐occurring pairs of invasive and native species from low fertility Hawkesbury Sandstone‐derived soil were grown under low and high nutrient availability. We tested the hypotheses that native species would be competitively superior at low nutrient availability and have trait values associated with a resource conservation strategy while invasive species would be competitively superior at high nutrient availability and have trait values associated with a resource acquisition strategy. We found that nutrient availability did not mediate competitive interactions between invasive and native species. Instead, two invasive and one native species were always competitively superior irrespective of nutrient availability. Competitively superior species displayed a mixture of both resource conservation and acquisition strategies at low and high nutrient availability. In support of previous studies, we found that the a priori classification of invasive and native species does not predict competitive superiority at varying nutrient levels. Rather, species specific differences in trait values provide a competitive advantage in response to nutrient availability. 相似文献
19.
基于SOFM网络对黄土高原森林生态系统的养分循环分类研究 总被引:2,自引:0,他引:2
对森林生态系统进行分类是认识森林生态过程的根本途径,传统的从结构角度对森林生态系统分类只能反映森林的外在特征,而无法从功能角度区别森林的本质差异.通过对黄土高原3个生物气候区18个不同森林生态系统的养分循环特征测算和分析,选取了能全面反映养分的积累和分布(生物量、枯落物积累量、养分积累量)、循环通量(年吸收量、年存留量、年归还量)以及养分循环效率(循环系数、利用系数、养分生产力)等多方面指标作为分类指标体系,利用自组织映射特征网络(SelfOrganizing Feature Maps,SOFM)聚类方法,从养分循环的角度将黄土高原森林生态系统划分为2个一级类型,6个二级类型.该分类结果与实际较符,从而探索了森林生态系统的功能分类方法,也验证了SOFM网络模型应用于森林养分循环分类的可行性. 相似文献
20.
Nutrient cycling is fundamental to ecosystem functioning. Despite recent major advances in the understanding of complex food web dynamics, food web models have so far generally ignored nutrient cycling. However, nutrient cycling is expected to strongly impact food web stability and functioning. To make up for this gap, we built an allometric and size structured food web model including nutrient cycling. By releasing mineral nutrients, recycling increases the availability of limiting resources for primary producers and links each trophic level to the bottom of food webs. We found that nutrient cycling can provide a significant part of the total nutrient supply of the food web, leading to a strong enrichment effect that promotes species persistence in nutrient poor ecosystems but leads to a paradox of enrichment at high nutrient inputs. The presence of recycling loops linking each trophic level to the basal resources weakly affects species biomass temporal variability in the food web. Recycling loops tend to slightly dampen the destabilising effect of nutrient enrichment on consumer temporal variability while they have opposite effects for primary producers. By considering nutrient cycling, this new model improves our understanding of the response of food webs to nutrient availability and opens perspectives to better link studies on food web dynamics and ecosystem functioning. 相似文献