共查询到20条相似文献，搜索用时 395 毫秒
1.
2.
为了评价耐草甘膦转基因大豆对土壤线虫的影响,在网室盆栽试验条件下,研究了成熟期耐草甘膦转基因大豆M88根际土壤线虫丰度、营养类群组成和生态学指数以及土壤环境因子和线虫群落之间的相关性。结果表明：试验共分离鉴定出23个土壤线虫属,8个功能群,其中非转基因大豆中黄13（Z13）种植条件下分离鉴定出土壤线虫23属,耐草甘膦转基因大豆M88种植条件下分离鉴定出土壤线虫21属;耐草甘膦转基因大豆M88的土壤线虫平均丰度为（1143．42±135．04）·100g^-1干土,显著高于（P〈O．05）非转基因大豆中黄13[（756．83±141．33）·100g^-1干土】;耐草甘膦转基因大豆M88显著升高了杂食捕食性线虫拟桑尼属（Thorneella）的相对丰度（P〈0．01）。虽然非转基因大豆中黄13种植条件下的自由生活线虫成熟度指数脚和结构指数s,显著低于耐草甘膦转基因大豆M88（P〈0．05）,但是两种大豆种植条件下土壤线虫的Shannon—Wiener多样性指数日’、属丰富度指数GR和营养多样性指数TD均无显著差异,说明耐草甘膦大豆M88对线虫群落结构多样性影响不显著。冗余分析RDA排序图显示：线虫功能组Om4和土壤有机质OM呈显著的正相关,而与硝态氮NN呈显著的负相关。 相似文献
3.
4.
在2013年对大连市大魏家镇海水入侵污染区域进行了土壤理化性质和线虫群落调查,在此基础上,应用线虫多样性指数和功能类群指数研究海水入侵土壤盐渍化以及不同土地利用方式对土壤线虫群落结构的影响。研究期间共鉴定出土壤线虫30科48个属。其中食细菌类群的比例最高,共17属,占总数42.81%;其次为杂食/捕食类群,共9个属,占总数25.26%。优势属为Plectus。结果显示:海水入侵已造成该地区土壤盐渍化;土壤盐分与线虫生态指数SR、f/b、NCR、PPI、MI、PPI/MI、PP%、FF%、BF%和OP%存在显著的相关关系;土地利用方式、土壤盐分对线虫群落的生态指数影响显著,是影响该地区土壤线虫群落结构的主要因素。通过开展土壤线虫对海水入侵土壤盐渍化响应的研究,为促进沿海受海水污染区土壤生态系统的健康发展提供科学依据。 相似文献
5.
6.
研究了引自意大利的3种番茄抗性砧木对温室土壤根结线虫二龄幼虫的控制作用以及对土壤自由生活线虫的影响。供试温室土壤共鉴定12科26属自由生活线虫,分属食细菌性线虫、食真菌性线虫、植食性线虫和杂食性线虫4种营养种群。试验结果表明,3种抗性砧木均显著地降低了嫁接苗植株根际土壤中根结线虫工龄幼虫（J2）的密度,从而控制了根结线虫病的发生;与不种植番茄的空白对照相比,种植番茄促进了根际自由生活线虫的繁殖,但抗性砧木根际自由生活线虫的密度小于感病对照“FA189”。所有处理根际自由生活线虫优势种群为食细菌性线虫。 相似文献
7.
为了解西藏墨脱嘎隆拉山铁杉林土壤生态系统线虫群落的结构及多样性特征，课题组于2017年9月对嘎隆拉山铁杉林不同生境土壤0-25cm深度范围的线虫群落进行了调查。采用种类组成、个体密度、多样性指数、功能性指数等特征值分析了土壤线虫群落的结构及多样性特点。并且，对嘎隆拉山铁杉林土壤线虫群落结构与土壤理化性质之间的关系进行了冗余分析及线性相关性分析。结果显示，嘎隆拉山铁杉林土壤线虫隶属于5目29科34属，个体密度平均278条/100g干土，土层间无明显差异；群落优势属为垫咽属和细齿属；食真菌性线虫是最主要的营养类群；土壤有机质以真菌降解途径为主；指数MI、PPI 值则说明了嘎隆拉山铁杉林生态系统受到干扰较小，成熟度高，目前处于相对稳定的状态。 相似文献
8.
根据土壤水分平衡方程，估算了我国北方地区无降水情况下土壤分减少到凋萎湿度所需的时间，以此来提示极端干旱的胁迫度，时间短表示胁迫度越强。在此基础上，讨论了灌溉和温室效应对胁迫度的可能影响。结果表明，北方地区夏季和春、秋季极端农业干旱出现的时间尺度为月、季长度、意味着这一地区存在着出现极端农业干旱的潜威胁。比较而言，夏季胁迫度明显强于春、秋季；西北华北西部强于江淮等地。灌溉可有效地减少极端农业干旱发生 相似文献
9.
长期施肥对哈尔滨黑土土壤线虫群落的影响 总被引：2，自引：0，他引：2
土壤线虫作为土壤生态系统中重要的组成部分,在养分转化及物质循环中起着重要作用。为研究长期施肥对土壤线虫群落的影响,在农业部哈尔滨黑土生态环境重点野外科学观测试验站进行了长期施用有机肥、氮肥、磷肥、钾肥及不施肥处理的田间试验。结果表明:长期施肥对土壤线虫群落组成及线虫群落中不同营养类群的相对丰度均产生一定的影响。长期施肥条件下,土壤线虫种群的种类数量呈下降的趋势,除单施氮肥处理外,其余施肥处理土壤食细菌线虫的相对丰度均显著高于不施肥处理,而植物寄生线虫相对丰度则显著低于不施肥处理;从土壤线虫生态指数看,施肥处理自由生活线虫成熟度指数(MI)均低于对照,而施用有机肥及磷肥处理的土壤WI值显著高于不施肥对照;土壤线虫群落的变化表明土壤线虫群落对施肥产生了响应,可以用作施肥对土壤质量变化影响的生物学指标。 相似文献
10.
11.
N.R. Maslen 《Soil biology & biochemistry》2006,38(10):3141-3151
Nematode worms are one of the most important soil faunal groups in Antarctica. However, relatively little is known about their wider distribution, biogeography and history in the region, and taxonomic information remains confused or incomplete. Here, we hypothesise that the Alexander Island (southern maritime Antarctic) fauna includes elements that have survived (at least) the period of Pleistocene glaciation in situ, forming a regional centre of endemism and biodiversity hotspot. We describe nematological surveys carried out across a latitudinal gradient between 68 and 77°S along the southern Antarctic Peninsula, comparing the data obtained with the maritime Antarctic fauna described in the few previous studies between northern Marguerite Bay and the South Orkney Islands (60-68°S). In general, our survey supports previous findings of a lack of overlap at species level between the maritime and continental Antarctic biogeographical zones, with the large majority of specimens obtained from all survey sites being attributable to known maritime or new and currently endemic taxa. However, collections from Alexander Island, Alamode Island and the most westerly site sampled, Charcot Island, include specimens morphologically very close to two known continental Antarctic species, which may indicate a link between the two regions. The fauna obtained at the northern study sites (ca. 68°S, Adelaide Island, Marguerite Bay) closely matches that described previously. However, in contrast with widely described patterns of decreasing diversity in other Antarctic biota, species richness increased markedly at locations on Alexander Island (ca. 72°S), including a substantial element of undescribed species (50% of taxa across all locations, 40% of taxa found on Alexander Island). Finally, the most southerly samples obtained, from inland nunataks in Ellsworth Land (75-77°S), indicate a fauna that does not include nematodes, which is exceptional not only in an Antarctic context but also for soils worldwide. 相似文献
12.
Relative to volcanic sites in Iceland and Hawaii the Hg distribution ratio soil: air around Mt. Erebus (Ross Island, U.S. Antarctica) is anomously low. Air values for all three areas are similar. Differences are a reflection of extremely low soil levels at Antarctic sample sites. This condition appears to arise from the paucity of vegetation and lower degree of bio-concentration among Antarctic biota. 相似文献
13.
Distribution and abundance of soil fungi in Antarctica at sites on the Peninsula, Ross Sea Region and McMurdo Dry Valleys 总被引：1，自引：0，他引：1
Fungal abundance and diversity were studied from 245 soil samples collected in 18 distinct ice-free locations in Antarctica including areas in the McMurdo Dry Valleys, Ross Sea Region, and the Antarctic Peninsula. Cultivable fungal abundance in soil was found to be most positively correlated with percent carbon and nitrogen based on a Spearman’s rank correlation test of six soil parameters. Soil moisture and C/N ratio were also positively correlated with fungal abundance while pH and conductivity were negatively correlated. These results suggest that nutrient limitations in these highly oligotrophic environments are a primary factor in determining the distribution and abundance of indigenous fungi. Other effects of the extreme Antarctic environment likely affect fungi indirectly by limiting the distribution and abundance of plant-derived sources of carbon. 相似文献
14.
Acid soils are widespread and limit global plant production. Aluminum(Al)/manganese(Mn) toxicity and phosphorus(P) deficiency are the major limiting factors affecting plant growth and productivity on acid soils. Plants, however, have evolved various strategies to adapt to these stresses. These strategies include using both external and internal mechanisms to adapt to Al toxicity, regulating Mn uptake, translocation, and distribution to avoid Mn toxicity, and orchestrating a set of P transport me... 相似文献
15.
16.
南极半岛海洋气候区的土壤I.风化作用 总被引：2，自引：0，他引：2
南极海洋性气候区是南极风化与成土作用相对较强的地区。本在对本区气候特点进行分析的基础上，明确了冻胀风化是本区最主要的物理风化形式，强烈的现代地貌过程对本区风化与成土过程具有显影响。阐述了本区内化学风化的主要过程、机制与产物，同时指出生物因素在本区的岩石风化与原始土壤形成过程具有重要意义。 相似文献
17.
Although soil algae are among the main primary producers in most terrestrial ecosystems of continental Antarctica, there are very few quantitative studies on their relative proportion in the main algal groups and on how their distribution is affected by biotic and abiotic factors. Such knowledge is essential for understanding the functioning of Antarctic terrestrial ecosystems. We therefore analyzed biological soil crusts from northern Victoria Land to determine their pH, electrical conductivity (EC), water content (W), total and organic C (TC and TOC) and total N (TN) contents, and the presence and abundance of photosynthetic pigments. In particular, the latter were tested as proxies for biomass and coarse-resolution community structure. Soil samples were collected from five sites with known soil algal communities and the distribution of pigments was shown to reflect differences in the relative proportions of Chlorophyta, Cyanophyta and Bacillariophyta in these sites. Multivariate and univariate models strongly indicated that almost all soil variables (EC, W, TOC and TN) were important environmental correlates of pigment distribution. However, a significant amount of variation is independent of these soil variables and may be ascribed to local variability such as changes in microclimate at varying spatial and temporal scales. There are at least five possible sources of local variation: pigment preservation, temporal variations in water availability, temporal and spatial interactions among environmental and biological components, the local-scale patchiness of organism distribution, and biotic interactions. 相似文献
18.
N. S. Mergelov 《Eurasian Soil Science》2014,47(9):845-862
The properties and spatial distribution of soils and soil-like bodies in valleys of the coastal Larsemann Hills and Vestfold Hills oases—poorly investigated in terms of the soil areas of East Antarctica—are discussed. In contrast to Dry Valleys—large continental oases of Western Antarctica—the studied territory is characterized by the presence of temporarily waterlogged sites in the valleys. It is argued that the deficit of water rather than the low temperature is the major limiting factor for the development of living organisms and the pedogenesis on loose substrates. The moisture gradients in the surface soil horizons explain the spatial distribution of the different soils and biotic complexes within the studied valleys. Despite the permanent water-logging of the deep suprapermafrost horizons of most of the soils in the valleys, no gley features have been identified in them. The soils of the wet valleys in the Larsemann Hills oasis do not contain carbonates. They have a slightly acid or neutral reaction. The organic carbon and nitrogen contents are mainly controlled by the amount of living and dead biomass rather than by the humic substances proper. The larger part of the biomass is concentrated inside the mineral soil matrix rather than on the soil surface. The stresses caused by surface drying, strong winds, and ultraviolet radiation prevent the development of organisms on the surface of the soil and necessitate the search for shelter within the soil fine earth material (endoedaphic niche) or under the gravelly pavement (hypolithic niche). In the absence of higher plants, humified products of their decomposition, and rainwater that can wash the soil profile and upon the low content of silt and clay particles in the soil material, “classical” soil horizons are not developed. The most distinct (and, often, the only diagnosed) products of pedogenesis in these soils are represented by organomineral films on the surface of mineral particles. 相似文献
19.
Tancredi Caruso Francesca Borghini Andrea Colacevich 《Soil biology & biochemistry》2007,39(11):2949-2956
Soil fauna in the extreme conditions of Antarctica consists of a few microinvertebrate species patchily distributed at different spatial scales. Populations of the prostigmatic mite Stereotydeus belli and the collembolan Gressittacantha terranova from northern Victoria Land (Antarctica) were used as models to study the effect of soil properties on microarthropod distributions. In agreement with the general assumption that the development and distribution of life in these ecosystems is mainly controlled by abiotic factors, we found that the probability of occurrence of S. belli depends on soil moisture and texture and on the sampling period (which affects the general availability of water); surprisingly, none of the analysed variables were significantly related to the G. terranova distribution. Based on our results and literature data, we propose a theoretical model that introduces biotic interactions among the major factors driving the local distribution of collembolans in Antarctic terrestrial ecosystems. 相似文献
20.
Climate models predict significant future warming in polar regions. In the McMurdo Dry Valleys, Antarctica, projected summer climate warming is expected to increase snow and glacial melt, resulting in higher stream discharge, rising lake levels, and an increase in areas of moist soil, but the potential influence of warming and associated changes in hydrology on the soil ecosystem is poorly understood. To examine the effects of soil warming and changes in the availability of liquid water on populations of soil invertebrates and their habitat, we established a full-factorial warming and water addition experiment at one experimental site in each of the three hydrologic basins of Taylor Valley, Antarctica, and measured responses over 8 years. We hypothesized that an increase in temperature and moisture together would enhance habitat suitability for soil invertebrates thereby increasing abundance, biomass and diversity of the soil animal communities. Instead, warming treatments had an overall negative effect on density and body size of the microbial-feeding nematode Scottnema lindsayae, the dominant animal in the dry valleys, which decreased by 42% in warmed plots. While experimental moisture additions as a single annual pulse had no effect on nematodes, the surface flooding of one site from rapid melting of upslope subsurface ice (the result of an unusual natural warming event) drastically altered soil moisture, salinity, and animal communities; mortality of S. lindsayae increased and densities decreased. This extreme soil wetting event also resulted in an increase in chlorophyll a and populations of Eudorylaimus spp, a nematode species that prefers moist to wet habitats and feeds on soil micro-algae. Our results suggest that warming in the dry valleys could significantly affect soil nematode populations and species composition both directly and indirectly by altering species-specific habitat suitability for soil biota. 相似文献