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51.
Continuous monoculture problems, or replanting diseases, are one of the key factors affecting productivity and quality of Chinese medicinal plants. The underlying mechanism is still being explored. Most of the studies on continuous monoculture of Rehmannia glutinosa L. are focused on plant nutritional physiology, root exudate, and its autotoxicity. However, the changes in the diversity of microflora in the rhizosphere mediated by the continuous monoculture pattern have been remained unknown. In this study, terminal restriction fragment length polymorphism (T-RFLP) technique was used for fingerprinting fungal diversity in the rhizosphere soil sampled from the fields of R. glutinosa monocultured for 1 and 2 yr. The results showed that the structure of fungal community in consecutively moncultured rhizosphere soil was different from that in control soil (no cropping soil), and varied with the consecutive monoculture years (1 and 2 yr). The comprehensive evaluation index (D) of fungal community estimated by principal component analysis of fragment number, peak area, Shannon-Weiner index, and Margalef index was higher in 1 yr monoculture soil than that in 2 yr monoculture soil, suggesting that consecutive monoculture of R. glutinosa could be a causative agent to decrease the diversity of fungal community in the rhizosphere soil. 相似文献
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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
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Methane oxidation in forest soils removes atmospheric CH4. Many studies have determined methane uptake rates and their controlling variables, yet the microorganisms involved have rarely been assessed simultaneously over the longer term. We measured methane uptake rates and the community structure of methanotrophic bacteria in temperate forest soil (sandy clay loam) on a monthly basis for two years in South Korea. Methane uptake rates at the field site did not show any seasonal patterns, and net uptake occurred throughout both years. In situ uptake rates and uptake potentials determined in the laboratory were 2.92 ± 4.07 mg CH4 m−2 day−1 and 51.6 ± 45.8 ng CH4 g−1 soil day−1, respectively. Contrary to results from other studies, in situ oxidation rates were positively correlated with soil nitrate concentrations. Short-term experimental nitrate addition (0.20-1.95 μg N g−1 soil) significantly stimulated oxidation rates under low methane concentrations (1.7-2.0 ppmv CH4), but significantly inhibited oxidation under high methane concentrations (300 ppmv CH4). We analyzed the community structures of methanotrophic bacteria using a DNA-based fingerprinting method (T-RFLP). Type II methanotrophs dominated under low methane concentrations while Type I methanotrophs dominated under high methane concentrations. Nitrogen addition selectively inhibited Type I methanotrophic bacteria. Overall, the results of this study indicate that the effects of inorganic N on methane uptake depend on methane concentrations and that such a response is related to the dissimilar activation or inhibition of different types of methanotrophic bacteria. 相似文献
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微生物在有机物质分解、能量转移等生物地化循环中起着重要作用,研究养殖活动对沉积物中微生物多样性的影响对正确评价近海生态系统结构和功能具有重要意义.结合沉积物的理化分析(T、pH、Eh和SO2-),通过T-RFLP(末端限制性片段长度多态性)分析了象山港网箱养殖对近海不同深度沉积物中细菌群落结构和多样性的影响,构建了对照区0-5 cm沉积物样品的细菌16S rRNA基因克隆文库,并进行了系统发育分析.结果表明,近海网箱养殖活动不但使象山港沉积物Eh、pH值等理化性质有所改变,而且使细菌的群落结构也发生了变化,变形细菌纲细菌的相对丰度降低,细菌群落的多样性和均匀度也显著降低,致使近海沉积物细菌群落由多样性高的稳定结构向多样性降低的不稳定结构转变. 相似文献
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《农业科学学报》2019,18(6):1360-1368
Saline area is an important reserve resource of arable land, however, the effects of soil microorganisms on the soil fertility in saline coastal ecosystems remain poorly understood. The salinity effects on soil microorganisms, nutrient availabilities and their relationships were studied in soils along a salinity gradient. A total of 80 soil samples were collected from 16 sites at four salinity levels(non-saline soil, salt content1 g kg–1; low salinity soil, salt content=1–2 g kg–1; middle salinity soil, salt content=2–4 g kg–1; high salinity soil, salt content4 g kg–1). The results showed that the salinity increased soil pH and exchangeable Na percent, but decreased soil organic matter, soil exchangeable K, and soil microbial biomass. Both the abundance and community composition of soil bacteria and fungi were significantly different between the non-saline and the saline soils. The predominant genera of soil bacteria(Planctomyces and Archangium, positive for carbon fixation) and fungi(Hydropisphaera, efficient in lignin degradation) changed with the increasing soil salinity and the decreasing soil organic matter. In summary, soil salinity changed the abundances of soil bacterial, fungal, and arbuscular mycorrhizal communities and, subsequently, affected their function in saline coastal ecosystems. 相似文献
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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
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乌鲁木齐10号泉水体细菌群落结构的动态变化及响应模式初析 总被引：2，自引：1，他引：1
[目的]了解乌鲁木齐10号泉水体细菌多样性及其对水文地球化学指标的响应.[方法]利用末端限制性片段长度多态性(Terminal Restriction Fragment length polymorphism,T- RFLP),对不同日期水体细菌多样性进行分析,所获信息与水文地球化学指标进行典型相关分析.[结果]通过各样品水体细菌类群的多样性指数计算和样品间相似性分析共同显示,乌鲁木齐10号泉不同日期水体细菌呈现随机性动态变化;典型相关分析(Canonical correspondence analysis,CCA)显示水体细菌群落结构与H2S、CH4、F-三项水文地球化学指标呈显著正相关,并且受多种水文地球化学指标的共同影响.[结论]乌鲁木齐10号泉水体细菌类群表现为随机性动态变化,且可对水文地球化学元素产生响应. 相似文献
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《农业科学与技术》2016,(3):655-661
Plant invasions could significantly alter arbuscular mycorrhizal (AM) fungal communities, but the effect may vary with plant species and local environments. Identifying changes in the AM fungal community due to plant invasion could improve our understanding of the invasion processes. Here, we examined the AM fungal community composition both in roots and rhizo-sphere soils of the invasive plant Cenchrus incertus and the dominant native plant Setaria viridis in a typical steppe in Inner Mongolia by using terminal restriction fragment length polymorphism analyses (T-RFLP). The results showed that AM fungal abundance in the rhizosphere soils of C. incertus was significantly lower than that of S. viridis. The AM fungal community com-position in the rhizosphere soils of the two plant species also largely differed. In general, AM fungal community structures in roots corresponded very wel to that in rhizosphere soils for both plant species. The dominant AM fungal type both in invasive and native plants was T-RFLP 524bp, which represents Glomus sp. (Virtual taxa 109 and 287). Three specific T-RF types (280, 190 and 141bp) were significantly more abundant in C. incertus, representing three clusters in Glomus which also named as VT (virtual taxa) 287, 64 and 214, Rhizophagus intraradices (VT 113) and Diversispora sp. (VT 60). While the specific T-RF types, 189 and 279bp, for S. viridis, only existed in Glomus cluster 1 (VT 156), were significantly less abundant in C. incertus. These results indicated that AM fungi might play an important role in the invasion process of C. incertus, which stil remains to be fur-ther investigated. 相似文献
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