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林地砍伐开垦对土壤酶活性及养分的影响 总被引：15，自引：1，他引：15
由土壤微生物生命活动和植物根系产生的土壤酶,不但在土壤物质转化和能量转化过程中起主要的催化作用,而且通过它对进入土壤的多种有机物质和有机残体产生的生命化学转化,使生态系统的各组分间有了功能上的联系,从而保持了土壤生物化学的相对稳衡状态［１］。土壤酶作... 相似文献
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通过模拟大气中臭氧浓度(100 nl · L-1和150 nl · L-1)的升高,观察对冬小麦不同生育期(拔节期、孕穗期、抽穗期、灌浆期、成熟期)的土壤中酶活性的影响,研究结果表明,随着生育时期的推进,土壤过氧化氢酶和多酚氧化酶活性均呈先降低后升高的趋势,抽穗期达最低值,拔节期和成熟期活性较大.转化酶和脲酶随呈现先增加后降低的变化,抽穗期达最高值,后出现急剧下降的趋势.方差分析表明,在臭氧胁迫下土壤过氧化氢酶、多酚氧化酶和转化酶活性在成熟期时均显著高于OTC对照(P<0.05).脲酶活性在生育前期高浓度臭氧处理显著地高于对照,低浓度影响不显著. 相似文献
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Felicity V. Crotty Sina M. Adl Rod P. Blackshaw Philip J. Murray 《The Journal of eukaryotic microbiology》2012,59(6):520-526
The soil is probably the most diverse habitat there is, with organisms ranging in sizes from less than 1 μm to several metres in length. However, it is increasingly evident that we know little about the interactions occurring between these organisms, the functions that they perform as individual species, or together within their different feeding guilds. These interactions between groups of organisms and physical and chemical processes shape the soil as a habitat and influence the nature of the soil food web with consequences for the above‐ground vegetation and food web. Protists are known as one of the most abundant groups of bacterivores within the soil; however, they are also consumers of a number of other food sources. Even though they are responsible for a large proportion of the mineralisation of bacterial biomass and have a large impact on the C and N cycles within the soil they are regularly overlooked when investigating the complete soil food web. Recently, stable isotopes have been used to determine trophic interactions and here we describe how this technique has been used to highlight linkages between protists and the soil food web. 相似文献
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Analysis of plant–frugivore interactions provides a quantitative framework for integrating community structure and ecosystem function in terms of how the roles and attributes of individual species contribute to network structure and resilience. In this study, we used centrality metrics to rank and detect the most important species in a mutualistic network of fruit‐eating birds and plants in a cloud forest in the Colombian Andes. We identified a central core of ten bird and seven plant species in a network of 135 species that perform dual roles as local hubs and connectors. The birds were mostly large forest frugivores, such as cracids, cotingas, and toucans, which consume fruits of all sizes. The plants were species of intermediate successional stages with small‐ to medium‐sized seeds that persist in mature forest or forest borders (e.g., Miconia, Cecropia, Ficus). We found the resilience of our network depends on super‐generalist species, because their elimination makes the network more prone to disassemble than random extinctions, potentially disrupting seed‐dispersal processes. At our study site, extirpation of large frugivores has already been documented, and if this continues, the network might collapse despite its high diversity. Our results suggest that generalist species play critical roles in ecosystem function and should be incorporated into conservation and monitoring programs. 相似文献
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植物对土壤有效养分的影响是植物竞争取胜的重要生态策略之一, 土壤酶活性对土壤有效养分的变化具有重要作用。该文研究了紫茎 泽兰(Ageratina adenophora)单种(A)、非洲狗尾草(Setaria sphacelata)单种(S)和两物种混种(A+S)群落4种重要的土壤酶活性和土壤养分的 变化及其规律, 并对土壤酶活性与土壤养分进行了相关分析。结果表明: 1)群落S土壤有效氮(NH4+-N和NO3--N)含量高于群落A对应养分含量, 而与群落A＋S该养分含量没有显著差异; 群落S土壤有效磷和有效钾含量低于群落A对应指标, 而群落A＋S其含量最低。2)群落S、A+S和A土壤蛋 白酶和脲酶活性的高低次序分别为S>A＋S>A、A＋S>S>A; 群落A+S、S和A磷酸酶活性依次升高; 群落A+S、A和S蔗糖酶活性依次降低。3)在生长 过程中, 3类群落土壤NO3--N、有效磷和有效钾含量在生长初期(5月)最高, 随后逐渐降低; 土壤NH4+-N含量呈现单峰趋势, 在生长后期(9月)最 高。3类群落土壤蛋白酶和蔗糖酶活性随生长时间推移而升高, 在生长末期(11月)最高; 土壤磷酸酶和脲酶酶活性在生长过程中呈现单峰趋势, 在生长旺盛期(7月)最高。3类群落间土壤酶活性与土壤肥力具有较一致的相关性。由此推断, 非洲狗尾草对土壤含氮化合物的活化能力比紫茎 泽兰强, 且在种间竞争中能够强烈抑制紫茎泽兰对土壤含磷、含钾化合物的活化能力是其竞争取胜的可能原因; 不同植物群落土壤酶活性的差 异是引起土壤有效养分变化的重要驱动机制之一。 相似文献
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为研究天坑负地形生境土壤酶活性、养分和木本植物多样性的分布特征和内在联系,该文以广西大石围天坑群天坑森林为研究区,基于天坑坑内—坑口—坑外群落多样性调查和土壤生境调查,采用相关性分析和冗余分析方法,探究木本植物物种多样性与土壤因子间的耦合关系。结果表明：(1)坑内木本植物有21种31属20科,坑口木本植物有91种58属58科,坑外木本植物有47种30属30科,天坑坑内Margalef指数和Patrick指数显著低于天坑坑口和坑外生境,沿天坑坑内—坑口—坑外生境变化,物种分布总体较为均匀,但物种数量增多。(2)天坑坑外土壤全氮含量显著高于坑内和坑口生境,坑内的土壤全镁、土壤全磷和土壤速效磷含量显著高于坑口和坑外生境,坑外的土壤碱性磷酸酶和土壤脲酶活性显著高于坑口和坑内生境,表明天坑坑内土壤磷含量较高,但土壤酶活性总体偏低。(3)物种多样性与土壤养分、土壤酶活性相关性强。综上表明,天坑生境对物种多样性、土壤酶活性及土壤养分含量的分布特征影响较大,土壤速效磷、土壤碱性磷酸酶、土壤含水量、土壤脲酶、土壤全镁和土壤全磷是影响天坑森林木本植物物种多样性的关键因子。该研究为喀斯特地区植物资源的保护与... 相似文献
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西宁南山区植被退化情况严重,人工造林植被恢复被看作是最有效的恢复手段,其中选择合适造林树种尤为关键。选择人工种植的唐古特白刺Nitraria tangutorum、柠条Caragana korshinskii、西北小蘗Berberis vernae和短叶锦鸡儿Caragana brevifolia共4种灌木树种造林试验区为研究对象,通过测定根际和非根际土壤微生物数量、酶活性及养分含量,综合比较种植4种灌木树种根际和非根际土壤肥力差异,科学评价其对土壤的改善效果。研究表明:(1)土壤微生物数量和酶活性总体呈现出根际高于非根际的规律,仅放线菌数量和脲酶活性出现了根际低于非根际现象。(2)土壤养分方面,4种灌木根际土壤和非根际土壤p H值、全N、全P、全K含量差异不显著,有机质、有效P、速效K含量均呈现出根际非根际,而碱解N则是根际非根际。(3)土壤酶活性与土壤微生物数量相关性不显著,土壤有机质含量与土壤细菌、真菌数量呈极显著正相关,有效P含量与土壤细菌、真菌和放线菌数量呈极显著正相关,速效K含量与过氧化氢酶、酸性磷酸酶活性呈显著正相关,全N、碱解N含量均与脲酶活性呈显著正相关。(4)从土壤肥力综合水平来看,根际非根际,其中根际土壤中西北小蘗柠条短叶锦鸡儿唐古特白刺,研究结果表明西北小蘗和柠条能大幅提高土壤肥力,改良土壤效果较好。 相似文献
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本文运用传统统计方法研究了典型喀斯特峰丛洼地4个植被演替阶段(草地、灌木林、次生林、原生林)表层(0—15 cm)土壤养分的空间分异特征,并分析其成因。结果表明：(1)不同植被演替阶段土壤养分（有机碳、全氮、碳氮比、全磷、全钾、碱解氮、速效磷、速效钾）及pH值有明显差异（P<0.05）;除全钾外,其他养分含量均随植被正向演替而增加。(2)地貌部位对养分含量的影响不尽一致：各植被演替阶段的磷、钾及原生林的碳氮均符合养分的“洼积效应”,只有受人为干扰较强的草地、灌木林、次生林的碳氮养分存在随坡位升高而增加的现象。通过本研究得知,植被演替对养分积累具有积极作用;磷素（速效磷3.55—11.41 mg/kg）、钾素（速效钾64.05—105.75 mg/kg）是该区域的养分限制性因子;该区域养分的“倒置现象”并不普遍存在。 相似文献
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Hannah L. Farrell Ariel Lger Martin F. Breed Elise S. Gornish 《Restoration Ecology》2020,28(Z4):S307-S310
Better understanding of the connection between aboveground plant communities and belowground soil organisms and processes has led to an explosion in recent research on the applications of this link to the field of ecological restoration. Research is only beginning to have the capacity to link soil organisms and specific ecosystem functions. Establishing general ecological principles of the role microbial communities have during ecological restoration is also still in its infancy. As such, the literature is at a critical point to generate a Special Feature that brings together novel approaches of linking soil and restoration to promote more regular inclusion and consideration of soil organisms and soil‐based processes in ecological restoration. In this special feature, we bring together nine research articles from different ecosystems that study the relationship between restoration activities, soil microbial communities, and soil properties. From these research articles, we describe two primary themes: (1) research on the impacts of ecosystem‐specific restoration activities on soil organisms and processes and (2) research testing methods of soil manipulation to improve restoration outcomes. We hope to inspire readers and restoration practitioners to consider soil microbes and soil processes in their research, restoration projects, and world views. 相似文献
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Ivana Alejandra Cavello Brenda Bezus Adalgisa Martinez Gabriela Garmendia Silvana Vero Sebastián Cavalitto 《Geomicrobiology journal》2013,30(9):847-857
AbstractAntarctic and sub-Antarctic regions are – with Polar Regions, mountains and the deep sea – the most extreme environments on Earth because of its low temperatures, dryness, high incidence of solar radiation and low nutrient availability. Nevertheless, microorganisms have successfully colonized these regions. In this study, culturable yeasts from soil samples collected from two different locations, a human-impacted area (Encerrada Bay) and a largely pristine and naturally vegetated area near Lago Escondido city (54°39′0″S, 67°46′48″W) from Tierra del Fuego province, Argentina were identified and characterized at different levels. They were characterized and classified as psychrotolerant and were considered as moderately halotolerant because of their ability to grow in the presence of 1.5?M of NaCl. Yeasts from phylum Ascomycota were affiliated to five genera: Candida, Yarrowia, Debaryomyces, Nadsonia, and Wickerhamiella, whereas from phylum Basidiomycota yeasts were affiliated to six genera: Naganishia, Rhodotorula, Leucosporidum, Tausonia, Cystofilobasidium, and Apiotrichum. Most of the yeasts demonstrated at least one extracellular enzymatic activity (mainly β-glucosidase, esterase, and protease activities). One isolate identified as Tausonia pullulans showed significant activity across the eight enzyme types tested. In light of these findings, Tierra del Fuego province could be considered as a cold environment with a potential source of cold-adapted yeasts producing industrially relevant cold-active enzymes. 相似文献
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1. Experimental channels were installed at the outlet of a small Canadian Shield lake to study the role of light and nutrients on the regulation of periphyton and invertebrate biomass and taxonomic composition. Light (93% reduction) and nutrients (four-fold increase of ambient total phosphorus (TP) concentration) were manipulated in a factorial design experiment.
2. Periphyton chlorophyll a (Chl a ), measured four times during the 12-week experiment, increased due to higher irradiance but was unaffected by phosphorus enrichment. Over the experiment, periphyton biomass was, on average, three times higher in open than in shaded channels.
3. Algal taxonomic and growth form composition were affected by light and phosphorus enrichment. The proportion of cyanophytes was significantly higher in unenriched, shaded channels (45%) compared to the three other treatments. Single cells and colonial forms were dominant in shaded channels, whereas filamentous and chain-forming algae were prevalent in open channels.
4. Total invertebrate biomass remained unchanged over time and among treatments. At the beginning of the experiment, all the channels were dominated by Chironomidae and filter feeders (Simuliidae and Hydropsychidae). After 55 days, filter feeders became clearly dominant (60%) in all treatments except in the enriched, open channels where there was a significant shift in the functional group composition toward grazers (snails and oligochaetes). Among filter feeders, Simuliidae increased in shaded channels. 相似文献
2. Periphyton chlorophyll a (Chl a ), measured four times during the 12-week experiment, increased due to higher irradiance but was unaffected by phosphorus enrichment. Over the experiment, periphyton biomass was, on average, three times higher in open than in shaded channels.
3. Algal taxonomic and growth form composition were affected by light and phosphorus enrichment. The proportion of cyanophytes was significantly higher in unenriched, shaded channels (45%) compared to the three other treatments. Single cells and colonial forms were dominant in shaded channels, whereas filamentous and chain-forming algae were prevalent in open channels.
4. Total invertebrate biomass remained unchanged over time and among treatments. At the beginning of the experiment, all the channels were dominated by Chironomidae and filter feeders (Simuliidae and Hydropsychidae). After 55 days, filter feeders became clearly dominant (60%) in all treatments except in the enriched, open channels where there was a significant shift in the functional group composition toward grazers (snails and oligochaetes). Among filter feeders, Simuliidae increased in shaded channels. 相似文献
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消落带土壤生态环境对水库水质及坡岸稳定性具有较大影响,土壤酶活性具有驱动土壤物质循环进而影响生态系统的功能。本文以三峡库区梨香溪消落带土壤为研究对象,研究了四个海拔梯度和五种植被样地的土壤蔗糖转化酶、脲酶、碱性磷酸酶和蛋白酶的活性及相关环境因子。结果表明,在不同海拔样地中,表层土壤的有机质、总氮、总磷和有效磷的含量均高于土壤下层,并且有效磷和总磷含量随海拔高度的增加而增大。四种土壤酶活性随高程的增加均总体呈现出增大的趋势。除脲酶外,167~180 m样地的下层土壤的土壤酶活性均高于165 m样地。在不同植被样地中,苔藓结皮样地的表层土壤中,蔗糖转化酶、碱性磷酸酶和蛋白酶的活性均为最大。有植被覆盖的样地土壤酶活性和土壤有机质、总氮、总磷和有效磷含量均高于裸地,其中虎杖和藻结皮植被对土壤的养分和土壤酶活性影响作用高于狗压根和苔藓结皮。四种土壤酶的酶活性与土壤总氮、总磷、有效磷和有机质含量大体都呈现正相关关系。以上结果表明,消落带土壤酶活性和土壤肥力供给能力受水淹影响,藻类结皮和苔藓结皮对消落带土壤肥力具有促进作用。 相似文献
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为深入了解川西亚高山-高山森林冬季生态学过程,于2008年11月—2009年10月,在土壤冻结初期、冻结期和融化期及植被生长季节,研究了不同海拔(3582 m、3298 m和3023 m)岷江冷杉林土壤养分动态及其对季节性冻融的响应。3个海拔森林土壤冬季具有较高养分含量,且随土壤冻融过程不断变化。土壤有机层可溶性碳和氮、铵态氮、硝态氮含量在冻结初期显著增加后快速降低,并随融化过程迅速增加后再次降低,而土壤可溶性碳和氮、硝态氮含量在冻结期变化不明显,铵态氮显著增加。矿质土壤层可溶性碳和氮、铵态氮含量也在冻结初期显著增加后降低,而土壤可溶性氮、铵态氮和硝态氮在冻结期显著增加,并在融化期经历一个明显的含量高峰。海拔和土层的交互作用显著影响土壤可溶性碳和硝态氮含量,土壤养分含量与土壤温度的相关性随海拔差异而不同。这表明季节性冻融期是土壤生态过程的重要时期,土壤冻融格局显著影响川西亚高山-高山森林土壤养分动态。 相似文献
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Afforestation has been accepted as a key measure for preventing soil erosion on the Chinese Loess Plateau for 40 years. In this study, we assessed the ecological success of afforestation by comparing afforested with pre‐afforested (croplands) and natural recovery sites in a typical watershed on the Loess Plateau. We evaluated the ecosystem response in terms of vegetation structure, plant diversity, and several key ecological processes of soil moisture, soil nutrients, and soil anti‐erodibility. Compared with the croplands, we found that the following indexes were significantly enhanced in afforested sites: vegetation structure and species diversity (species richness, Margalef index, Shannon–Wiener index, and Sorensen's similarity index), soil nutrients (organic carbon, total nitrogen, extractable ammonium nitrogen, available potassium, and available phosphorous), and soil anti‐erodibility indexes (water‐stable soil aggregates, mean weight diameter, and the ratio of soil structure dispersion). Afforestation offered few additional advantages when compared with natural recovery sites. More importantly, afforestation had significant negative effects on soil desiccation, with negative impacts on the long‐term sustainability of these ecosystems. In order to develop self‐sustaining and functional ecosystems, our results suggest that natural revegetation offers a more adaptive and appropriate method of ecological restoration on the Loess Plateau. 相似文献
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This paper reports the results of a phytosociological and gradient analysis of the vegetation occurring along an altitudinal gradient from Turi (3100 m) to Cerro León (4250 m) on the western flank of the Andes in northern Chile (22°06′–22°22′ S; 68°15′–68°07′ W). Along the transect, the total cover of vegetation ranges from 2.5% at the lower end to 35.7% at 4000 m altitude. Four major physiognomic zones, including six associations are recognized within the transect studied: (1) The ‘Pre-Puna’ belt (2700–3150 m), characterized by a sparse cover of xerophytic subshrubs, including two associations: Acantholippia deserticola-Franseria meyeniana, which occurs over the sedimentary sands around Turi, and Franseria meyeniana-Helogyne macrogyne-Helianthocereus atacamensis, restricted to ravines and canyons. (2) The ‘Puna’ belt (3150–3850 m), physiognomically dominated by shrubs and presenting the highest vegetational cover, including the: Fabiana densa-Baccharis boliviensis, and Junellia seriphioides-Baccharis incarum-Lampaya medicinalis, associations. (3) The ‘High-Andean’ belt, localized above the ‘Puna’, including the Fabiana bryoides-Adesmia horrida and Oxalis exigua-Mulinum crassifolium associations. (4) The ‘Subnival’ belt, a high mountain semi-desert with a poorly developed vegetation. Only three species occur at the upper vegetational limit (4380 m). The phytosociological scheme proposed in this paper can be paralleled with that by Ruthsatz (1977) for the eastern flank of the Andes. A marked contrast in species richness and phytosociological complexity between these Andean regions is pointed out. Lower species richness of the Chilean transect is related to the presence of the Atacama desert, which extends from the coast up to 2700 m in the study area. 相似文献
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Matteo Montagna Andrea Berruti Valeria Bianciotto Paola Cremonesi Riccardo Giannico Fausto Gusmeroli Erica Lumini Simon Pierce Flavia Pizzi Federica Turri Gustavo Gandini 《Molecular ecology》2018,27(18):3671-3685
Biological diversities of multiple kingdoms potentially respond in similar ways to environmental changes. However, studies either compare details of microbial diversity across general vegetation or land use classes or relate details of plant community diversity with the extent of microbially governed soil processes, via physiological profiling. Here, we test the hypothesis of shared responses of plant and rhizosphere bacterial, fungal and metazoan biodiversities (especially across‐habitat β‐diversity patterns) along a disturbance gradient encompassing grazed to abandoned Alpine pasture, on acid soil in the European Central Alps. Rhizosphere biological diversity was inferred from eDNA fractions specific to bacteria, fungi and metazoans from contrasting plant habitats indicative of different disturbance levels. We found that soil β‐diversity patterns were weakly correlated with plant diversity measures and similarly ordinated along an evident edaphic (pH, C:N, assimilable P) and disturbance gradient but, contrary to our hypothesis, did not demonstrate the same diversity patterns. While plant communities were well separated along the disturbance gradient, correlating with fungal diversity, the majority of bacterial taxa were shared between disturbance levels (75% of bacteria were ubiquitous, cf. 29% plant species). Metazoa exhibited an intermediate response, with communities at the lowest levels of disturbance partially overlapping. Thus, plant and soil biological diversities were only loosely dependent and did not exhibit strictly linked environmental responses. This probably reflects the different spatial scales of organisms (and their habitats) and capacity to invest resources in persistent multicellular tissues, suggesting that vegetation responses to environmental change are unreliable indicators of below‐ground biodiversity responses. 相似文献
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《Journal of biological education》2012,46(2):106-108
This article describes a visit to the museum, where Penicillin was discovered in 1928, which would be of particular interest to future medical students 相似文献