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41.
套作对黄瓜根际土壤细菌群落结构的多样性影响 总被引：3，自引：0，他引：3
以设施蔬菜中的主要栽培种类黄瓜为研究对象,以毛葱、蒜为套作作物,利用T-RFLP(末端限制性片段长度多态性,Terminal Restriction Fragment Length Polymorphism)技术对套作黄瓜根际土壤细菌群落结构多样性进行了研究。结果表明:套作改变了黄瓜根际土壤细菌群落结构的多样性和优势菌群结构。套种毛葱的黄瓜根际土壤细菌群落结构多样性高于套种蒜的黄瓜根际土壤细菌群落结构多样性;在黄瓜定植前和拉秧期,套作处理的土壤细菌群落结构多样性有比对照高的趋势,而在根瓜期和盛瓜期套作处理的土壤细菌群落结构多样性有比对照低的趋势;毛葱的套作效果最佳,蒜套作次之。套作提高了黄瓜产量。 相似文献
42.
Annika Uibopuu Mari Moora Tim Daniell Maarja Öpik 《Soil biology & biochemistry》2009,41(10):2141-2146
Arbuscular mycorrhizal fungi (AMF) are important functional components of ecosystems. Although there is accumulating knowledge about AMF diversity in different ecosystems, the effect of forest management on diversity and functional characteristics of AMF communities has not been addressed. Here, we used soil inoculum representing three different AM fungal communities (from a young forest stand, an old forest stand and an arable field) in a greenhouse experiment to investigate their effect on the growth of three plant species with contrasting local distributions - Geum rivale, Trifolium pratense and Hypericum maculatum. AM fungal communities in plant roots were analysed using the terminal restriction fragment length polymorphism (T-RFLP) method. The effect of natural AMF communities from the old and young forest on the growth of studied plant species was similar. However, the AMF community from the contrasting arable ecosystems increased H. maculatum root and shoot biomass compared with forest inocula and T. pratense root biomass compared to sterile control. According to ordination analysis AMF inocula from old and young forest resulted in similar root AMF communities whilst plants grown with AM fungi from arable field hosted a different AMF community from those grown with old forest inocula. AMF richness in plant roots was not related to the origin of AMF inoculum. G. rivale hosted a significantly different AM fungal community to that of T. pratense and H. maculatum. We conclude that although the composition of AM fungal communities in intensively managed stands differed from that of old stands, the ecosystem can still offer the ‘symbiotic service’ necessary for the restoration of a characteristic old growth understorey plant community. 相似文献
43.
为研究大型底栖动物霍甫水丝蚓（Limnodrilus hoffmeisteri）对表层沉积物中细菌群落结构和多样性的影响,设计了沉积物-水微宇宙的实验,模拟太湖梅梁湾霍甫水丝蚓（Limnodrilus hoffmeisteri）的自然分布特征,运用末端限制性片段长度多态性技术（T-RFLP）比较了有无霍甫水丝蚓（Limnodrilus hoffmeisteri）分布的沉积物样品中细菌群落的动态变化。结果表明,水丝蚓组和对照组沉积物细菌群落结构相似性无显著差异（P〉0.05）,可见太湖梅梁湾目前的水丝蚓生物量引起的生物扰动对表层沉积物细菌群落结构影响不明显;实验中后期只在处理组中出现的206 bp以及处理组含量高于对照组的370 bp T-RFs都可能是Nitrosomonas属的氨氧化细菌,提示大型底栖动物霍甫水丝蚓的存在可能为氨氧化细菌提供了适合的生态位。 相似文献
44.
新疆沙尘暴源区塔克拉玛干空气真菌群落的T-RFLP分析 总被引：2，自引：0，他引：2
[目的]了解新疆塔克拉玛干沙漠周边地区空气真菌物种多样性及群落结构特征.[方法]应用末端限制性片段长度多态性(T-RFLP)技术分析和比较塔克拉玛干沙漠空气真菌多样性.[结果]塔克拉玛干沙漠周边且末地区的空气真菌物种多样性最高,尉犁地区最少,9个地区空气样品间相似性介于8.3;～41.9;,其中若羌和莎车地区的相似性最高,达到41.9;;尉犁地区与且末、叶城的相似性最低,为8.3;,与聚类分析结果大体上相一致.典型性相关分析(CCA)表明非生物环境因子(海拔、温度、风速等)影响空气真菌群落的多样性.[结论]塔克拉玛干沙漠周边9个地区空气真菌多样性较丰富,且各地区的优势真菌种群和丰度不同;限制性内切酶的种类对空气真菌群落信息的描述有较大影响. 相似文献
45.
末端限制性片段长度多态性技术(T-RFLP)在微生物群体分析上的应用与技术优化 总被引：2，自引：0，他引：2
末端限制性片段长度多态性技术(T-RFLP)是以荧光标记引物PCR为基础,根据末端限制性片段长度区分出微生物群体组成的一种微生物群体图谱法。本文综述了该方法在群体微生物分析上的应用及DNA提取、PCR扩增、酶切和数据分析等步骤的技巧与优化,总结了科学应用该技术的要求以及和多重PCR、gyrB基因等相结合的观点。 相似文献
46.
The progenitor of maize is Balsas teosinte (Zea mays subsp. parviglumis) which grows as a wild plant in the valley of the Balsas river in Mexico. Domestication, primarily targeting above-ground traits, has led to substantial changes in the plant's morphology and modern maize cultivars poorly resemble their wild ancestor. We examined the hypotheses that Balsas teosinte (accession PI 384071) has a) a different root system architecture and b) a structurally and functionally different rhizosphere microbial community than domesticated cultivars sweet corn (Zea mays subsp. mays accession PI 494083) and popping corn (Zea mays subsp. mays accession PI 542713). In a greenhouse experiment, five plants from each corn variety were grown in individual pots containing a Maury silt loam – perlite (2:1) mixture and grown to the V8 growth stage at which rhizosphere bacterial and fungal community structure was assessed using terminal restriction fragment length polymorphism and fatty acid methyl ester analysis. Functional characteristics of the rhizosphere were assayed by examining the potential activity of seven extracellular enzymes involved in carbon, nitrogen and phosphorus cycling. Root system architecture was characterized by root scans of sand grown plants at the V5 growth stage. Compared to the control the sweet corn rhizosphere had different bacterial and fungal community structure, decreased fungal diversity and increased bacterial abundance. Teosinte caused a significant change in the rhizosphere bacterial and fungal community structure and increased bacterial abundance, but no significant decrease in bacterial or fungal diversity where the former was found to be significantly greater than in the sweet corn rhizosphere. Popping corn did not trigger significant changes in the bacterial or fungal diversity and bacterial abundance in the soil. The individual popping corn plants changed the bacterial and fungal communities in different directions and the overall effect on community structure was significant, but small. Of the enzymes analyzed, potential N-acetylglucosaminidase (NAG) activity was found to contributed most to the differentiation of teosinte rhizosphere samples from the other corn varieties. The teosinte root system had proportionally more very fine (diameter < 0.03 mm) roots than popping corn and sweet corn and it developed the highest root to shoot dry weight ratio, followed by popping corn. Sweet corn had significantly lower average root diameter than popping corn and teosinte and grew proportionally the least below-ground dry mass. The results allude to functional and structural differences in the rhizosphere microbial communities of the corn varieties that, with additional research, could lead to useful discoveries on how corn domestication has altered rhizosphere processes and how plant genotype influences nutrient cycling. 相似文献
47.
Fungi are key to the functioning of soil ecosystems, and exhibit a range of interactions with plants. Given their close associations with plants, and importance in ecosystem functioning, soil-borne fungi have been proposed as potential biological indicators of disturbance and useful agents in monitoring strategies, including those following the introduction of genetically modified (GM) crops. Here we report on the impact of potato crop varieties, including a cultivar that was genetically modified for its starch quality, on the community composition of the main phyla of fungi in soils, i.e. Ascomycota, Basidiomycota and Glomeromycota in rhizosphere and bulk soil. Samples were collected at two field sites before sowing, at three growth stages during crop development and after the harvest of the plants, and the effects of field site, plant growth stage and plant cultivar (genotype) on fungal community composition assessed using three phylum-specific T-RFLP profiling strategies and multivariate statistical analysis (NMDS ordinations with ANOSIM test). In addition, fungal biomass, arbuscular mycorrhizal colonization of roots and activities of extracellular fungal enzymes (laccases, Mn-peroxidases and cellulases) involved in degradation of lignocelluloses-rich organic matter were determined. Fungal community compositions, densities and activities were observed to differ significantly between the rhizosphere and bulk soil. The most important factors determining fungal community composition and functioning were plant growth stage for the rhizosphere communities and location and soil properties for the bulk soil communities. The basidiomycetes were the most numerous fungal group in the bulk soils and in the rhizosphere of young plants, with a shift toward greater ascomycete numbers in the rhizosphere at later growth stages. There were no detectable differences between the GM cultivar and its parental cultivar in terms of influence on fungal community structure of function. Fungal community structure and functioning of both GM- and parental cultivars fell within the range of other cultivars at most sampling moments. 相似文献
48.
In boreal forests ericaceous shrubs often dominate the forest floor vegetation. Nitrogen enrichment has been shown to decrease shrub abundance and in this study we explored whether it also affects the root associated fungal communities. Fine roots of Vaccinium myrtillus were collected in a Norway spruce dominated forest and of Vaccinium vitis-idaea in a Scots pine dominated forest. In both forests, nitrogen enrichment was experimentally induced by adding 12.5 and 50 kg N ha−1 yr−1 for 12 (spruce forest) and four (pine forest) years. Based on terminal restriction fragment length polymorphisms, subcloning and sequencing analyses, the root associated fungal communities were examined. We found 93 fungal species including Asco-, Basidio- and Zygo-mycota. In general, the Rhizoscyphus ericae aggregate was the most dominant and this was followed by Herpotrichiellaceae and Sebacina. Ordination analysis revealed that nitrogen enrichment did not change species composition of the fungal communities in neither the spruce nor the pine forest, while fungal community structures were clearly discriminated between the dominant shrub species in each forest. Similarly, no fungal species showed a significant response to nitrogen enrichment. Therefore, nitrogen enrichment appears to have no effect on root associated fungi of understorey dwarf shrubs in boreal forests, while it is clear that spruce and pine forests harbor distinctive communities of these fungi. 相似文献
49.
Nathalie J.A. Curlevski Ian C. Anderson John W.G. Cairney 《Soil biology & biochemistry》2010,42(1):14-20
Native rainforest tree plantations are increasingly viewed as potentially important for high value timber production and provision of a range of ecological services in tropical and subtropical areas. In order to determine the extent to which conversion of rainforest to native Araucariaceae plantation influences soil fungi, we compared soil fungal communities under native rainforest and 73-74 year-old Araucaria bidwillii, Araucaria cunninghamii and Agathis robusta plantations at Gadgarra State Forest, Queensland, Australia. Following direct extraction of DNA from soil, terminal restriction fragment length polymorphism (T-RFLP) analysis of rDNA internal transcribed spacer (ITS) regions was conducted. Ordination analysis of the T-RFLP data revealed significant separation of the fungal communities according to forest type along the first canonical axis, with the native rainforest samples separating from the three Araucariaceae plantations along the second axis. Overall, the most abundant ITS sequences in clone assemblages from the four forest types were Ascomycota, followed by Basidiomycota, Zygomycota and Chitridomycota, however their relative importance varied in individual forest types. The results indicate that conversion of tropical rainforest to monoculture plantations of native trees can significantly alter soil fungal diversity. 相似文献
50.
M’Barek Tamasloukht 《Soil biology & biochemistry》2007,39(7):1824-1827
Plant root exudates induce the transition from asymbiosis to presymbiosis in arbuscular mycorrhizal fungi. In order to get an insight into this developmental switch, two libraries of Gigaspora rosea and one library of Gigaspora gigantea were screened for fragments of genes that show enhanced RNA accumulation 1 h after addition of a semi-purified exudate fraction of carrot roots. Among 150 clones, 40 seemed to contain inserts of root exudate-induced genes. One of the genes, GrosRbp1, putatively encoding an RNA binding protein involved in developmental control showed RNA accumulation which correlates to the extent of stimulation of presymbiotic hyphal branching. 相似文献