添加猪粪对不同施肥历史土壤细菌群落的影响

为探讨粪肥携带的微生物对土壤微生物的影响,以长期施用粪肥和化肥的土壤为研究对象,耦合传统微生物学培养方法和现代分子微生物学方法,分析了猪粪和灭菌猪粪对2种土壤的细菌数量、群落结构和热代谢活性的影响.结果表明,以9.0t/hm2的用量施入时,猪粪和灭菌猪粪对两种土壤中的可培养细菌数量以及细菌16S-rRNA拷贝数均无明显影响;土壤中的土著微生物对猪粪携带的外源细菌在土壤中定殖具有明显的抑制作用,将2种土壤灭菌后添加猪粪,可培养细菌平均数量较未灭菌土壤分别增加45.96和96.21倍.粪肥输入的化学物质未导致土壤细菌群落结构和相对丰度发生明显变化;而粪肥输入的外源细菌Marinilabiaceae、Porphyromonadaceae、Bacteroidale和Pseudomonadaceae则可以在长期施用化肥的土壤中定殖并对相应的细菌丰度造成影响,但是在长期施用粪肥的土壤中,这些细菌在最开始就被抑制.添加粪肥提高了长期施用化肥土壤的微生物热代谢活性,但对长期施用粪肥的土壤无明显影响.长期施用化肥的土壤受粪源细菌的影响较大,而长期施用粪肥的土壤对粪肥的敏感度降低,对粪肥携带的外源细菌的抑制作用增强.

氨化-硝化复合菌剂对油枯有机肥氮氨化和硝化作用的影响

为了探讨在2种不同氨化-硝化复合菌剂作用下,油枯有机肥中有机氮在土壤中的氨化、硝化作用,以油枯商品有机肥为研究对象,通过室内温育培养法,研究添加氨化-硝化复合菌剂有机肥中有机氮在土壤中氨化和硝化过程。结果表明,添加氨化-硝化复合菌剂1和氨化-硝化复合菌剂2均可提高土壤氮的硝化速率(NNR),延长土壤硝化菌群的硝化活性;与未添加氨化-硝化复合菌剂油枯有机肥处理相比,培养60 d时添加氨化-硝化复合菌剂1、氨化-硝化复合菌剂2分别提高有机肥氮矿化后矿质氮累积量62.2 mg/kg和57.9 mg/kg;未添加氨化-硝化复合菌剂油枯有机肥中矿化出的矿质氮量占有机肥全氮量的比例为25.65%,添加氨化-硝化复合菌剂1、氨化-硝化复合菌剂2后,油枯有机肥中矿化出的矿质氮量占有机肥全氮量的比例分别为64.95%和61.53%,分别是未添加氨化-硝化复合菌剂油枯有机肥处理的2.5倍和2.4倍,表明2种氨化-硝化复合菌剂对油枯有机肥氮的氨化、硝化过程有较大促进作用。

Pollen and Phytolith Analyses of Ancient Paddy Fields at Chuodun Site, the Yangtze River Delta

A number of paddy fields pertaining to the Majiabang Cultures (5500-3800 years BC) were discovered during the archaeological excavations that were carried out since 1998 at the Chuodun site in the Yangtze River Delta. The pollen and phytolith analyses of two soil profiles from the northeastern part of this site were carried out to trace the agricultural practices of the Neolithic period. The phytolith results showed that rice domestication in the Yangtze River Delta could be traced back to as early as the Majiabang Culture. The pollen assemblage also revealed low levels of aquatic species, similar to that in modern paddy fields. This finding suggested that humans might have removed weeds for rice cultivation during the Neolithic period. Thus, pollen analysis in association with phytolith analysis was a promising method for identifying ancient paddy fields.

Characteristics of Soil Fertility of Buried Ancient Paddy at Chuodun Site in Yangtze River Delta, China

Field investigation and laboratory analysis of 22 ancient paddy soils excavated at Chuodun site, Kunshan City, Jiangsu Province, China were carried out in 2003 to （1） understand the basic characteristics of ancient paddy soils, （2） compare the difference of soil fertility between ancient paddy soils and recent paddy soils, and （3） inquire into mechanisms of the sustainability of paddy soil. The oldest paddy soils at Chuodun site can be dated back to Neolithic age, around 6000 aBP. These ancient fields were buried in about 1-m deep from the soil surface and their areas ranged from 0.32 to 12.9 m^2 with an average of 5.2 m^2. The paddy soils with 〉 5 000 pellets phytolith g^-1 soil were termed intensively cultivated paddy soils （ICPS） and those with 〈5000 pellets phytolith g^-1 soil were called weakly cultivated soils （WCPS）. The contents of organic carbon （OC）, and total N in the former were significantly higher than that in the latter. Ancient paddy soils had higher soil pH and C/N, total and available P, and lower contents of OC, DOC, total N, S, Cu, Fe, and available K, S, Fe, Mn, and Cu compared with recent paddy soils, which were attributed to application of chemical and manure fertilizers, pollution and acidification in recent paddy soils. The variation coefficients of OC and other nutrients in ancient paddy soils with higher PI were greater than that in ancient paddy soils with low PI, which indicated that human activities had a great impact on the spatial variability of soil nutrients. The contents of OC, total N, P and S in ancient paddy soils were higher than that in ancient moss of the same age, which indicated that planting rice during Majiabang culture period was beneficial to the accumulation of those life elements.

Effects of Arbuscular Mycorrhizal Fungi and Earthworm on Nematode Communities and Arsenic Uptake by Maize in Arsenic-Contaminated Soils

The influences of arbuscular mycorrhizal fungi (AMF,Acaulospora spp.and Glomus spp.) and rice straw and earthworms (RE,Eisenia foetida) on nematode communities and arsenic (As) uptake by maize (Zea mays L.) in Ascontaminated soils were examined in a field experiment conducted in Wujiang,Jiangsu Province,China.The experiment was designed as a 2 × 2 factorial with the factors of AMF (inoculated or uninoculated) and RE (added or not added).The results demonstrated that AMF inoculation led to significantly higher root colonization of AMF and root dry weight.Plants inoculated with both AMF and RE had the highest As concentrations in root.The number of total nematodes increased with AMF inoculation when RE was absent,and decreased with RE addition when AMF was inoculated.The improved abundance of nematodes with the AMF treatment implied that the tested AMF acted as food sources for fungivores.The abundances of omnivores-predators and plant parasites were reduced by earthworm activity.Twentyseven genera of nematodes were identified,with Filenchus dominant in all treatments.Trophic diversity,Shannon-Weaver diversity,Simpson dominance index,and species richness indicated higher species diversity,more proportionate species composition,evenly distributed species,and more food sources in the AMF,RE,and their interaction treatments.Maturity index showed a moderately disturbed environment due to As pollution.Besides enhancing plant uptake of contaminants,AMF and RE amendments could also improve soil health by restoring the structure of soil communities,as reflected by more stable nematode community structure.

决奈达隆致不良反应的文献分析

目的分析决奈达隆所致药品不良反应(ADR)的发生情况及临床特点,为其临床合理应用提供参考。方法通过检索中国知网、万方数据、维普网、PubMed、Web of Science、Embase数据库,收集决奈达隆致ADR的个案报道,并进行统计分析。结果共收集26篇符合条件的文献,涉及27例患者,共发生29例次ADR,男性15例,女性12例,主要为70~79岁的患者(51.86%),51.72%的ADR发生在用药1个月内。ADR累及系统/器官主要涉及心血管系统,其次是肝胆系统、皮肤及附属系统、呼吸系统,少见于泌尿系统和神经系统。结论使用决奈达隆初期应加强监测,警惕其ADR,以便发生ADR时能及时采取措施,以降低用药风险,提高临床疗效。

Bacterial Communities in a Buried Ancient Paddy Soil from the Neolithic Age

An ancient irrigated paddy soil from the Neolithic age was excavated at Chuodunshan Site in the Yangtze River Delta, close to Suzhou, China. The soil organic matter (SOM) content in the prehistoric rice soil is comparable to the average SOM content of present rice soils in this region, but it is about 5 times higher than that in the parent materials. As possible biomarkers to indicate the presence of the prehistoric paddy soil, the bacterial communities were investigated using the techniques of aerobic and anaerobic oligotrophic bacteria enumeration, Biolog analysis, and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The results showed that in the buried soil layers, the prehistoric paddy soil had the largest number of aerobic and anaerobic oligotrophic bacteria, up to 6.12 and 5.86 log cfu g-1 dry soil, respectively. The prehistoric paddy soil displayed better carbon utilization potential and higher functional diversity compared to the parent materials and a prehistoric loess layer. The Shannon index and richness based on DGGE profiles of bacterial 16S rRNA genes were higher in prehistoric paddy soil than those in the prehistoric loess soil. It might be concluded that the prehistoric irrigated rice cultivation accumulated the SOM in plowed soil layer, and thus increased soil bacterial populations, metabolic activity, functional diversity and genetic diversity. Bacterial communities might be considered as the sensitive indicators of the presence of the prehistoric paddy soil in China's Yangtze River Delta.

Effects of Arbuscular Mycorrhizal Fungi Communities on Soil Quality and the Growth of Cucumber Seedlings in a Greenhouse Soil of Continuously Planting Cucumber

A pot experiment was performed to determine the effects of arbuscular mycorrhizM fungi （AMF） communities on soil properties and the growth of cucumber seedlings in a degraded soil that had been used for continuous cucumber monoculture in a greenhouse for 15 years. In the experiment, AMF communities （created by combining various AMF species that were found to be dominant in natural farm soil） were inoculated into the degraded soil, and then the soil was planted with cucumber. Inoculation with AMF communities did not affect soil pH but increased soil aggregate stability and decreased the concentrations of salt ions and electrical conductivity （EC） in the soil. Inoculation with AMF communities increased the numbers of culturable bacteria and actinomycetes but reduced the number of fungi. AMF communities increased plant growth, soluble sugar content, chlorophyll content, and root activity compared to non-mycorrhizal or a single AMF species treatments. Improvements of soil quality and plant growth were greatest with the following two communities： Glomus etunicatum ＋ G. mosseae ＋ Gigaspora margarita ＋ Acaulospora lacunosa and G. aggregatum ＋ G. etunicatum ＋ G. mosseae ＋ G. versiforme ＋ G. margarita ＋ A. lacunosa. The results suggested that certain AMF communities could substantially improve the quality of degraded soil.

盐度对滨海土壤细菌多样性和群落构建过程的影响

滨海盐土是重要的农业土地后备资源。微生物是土壤中物质循环的关键动力,然而盐度对土壤微生物群落特征影响的研究还很缺乏。本研究采集滨海地区的土壤样品,研究非盐、轻盐和高盐3组不同盐度对土壤细菌数量、多样性和群落构建的影响。结果表明:与非盐和轻盐土壤相比,高盐土壤的脱氢酶活性和细菌数量显著降低,而细菌α多样性没有变化,细菌群落结构发生分异。利用零模型反演群落构建过程,发现盐度是细菌群落构建过程的主控因子,盐度主导的高确定性过程控制了滨海盐土细菌的群落结构。说明在现有的盐度范围内,高盐土壤中同样含有丰富的微生物种质资源,具有盐土改良的生物学基础,然而由于高确定性的群落构建机制,外源物种很难定殖于滨海盐土。因此,在利用微生物技术改良滨海盐土时,应尽可能筛选耐盐的土著菌种,提高定殖效率。

Microbial Community Changes Along a Land-Use Gradient of Desert Soil Origin

Soil harbors remarkably stabilize bacterial communities at the phylum level. However, no two soils have exactly the same structure of bacterial phyla. The structure of microbial community is strongly influenced by the type of land-use through changes in soil attributes. Using high-throughput pyrosequencing and quantitative polymerase chain reaction techniques, soil microbial community structures were investigated along a land-use gradient of 100- and 27-year farmlands, a 33-year Pinus forest, a 28-year poplar forest, and a 21-year shrubland, as well as a native desert from which all cultivated systems were converted. The results revealed that the dominant phylotypes in the native soil comprised primarily of Alphaproteobacteria, Actinobacteria, Bacteroidetes, and Firmicutes, accounting for 〉 71.4% of the total bacterial 16S rRNA sequence reads. Changes in land-use led to a significant decrease in these dominant phylotypes down to 33.4%. In contrast, the phylotypes with low abundance, such as Acidobaeteria, Chloroflexi, Nitrospira, and Gammaproteobaeteria, increased sharply from 4.5%-5.9% in the native soil to 20.9% 30.2% of the total 16S rRNA gene sequences in the cultivated soils except for the soil from the shrubland. These contrasting changes in the major taxa appear to be correlated with the changes in soil attributes. For instance, bacterial and archaeal amoA genes were found to be 960- and 3 800-fold more abundant in the soil from the 100-year farmland than the native soil. The changes in numerically less dominant nitrifying phylotypes are consistent with soil inorganic nitrogen dynamics. Quantification of the 16S rRNA genes demonstrated that bacteria and archaea were about two to three orders of magnitude more abundant in the cultivated soil than in the native soil. Hence, land-use type affects the soil bacterial community structure, which has profound consequences on ecosystem function.

Effects of Soil Depth and Season Variation on Community Structure of Arbuscular Mycorrhizal Fungi in Greenhouse Soils Planted with Watermelon

The characteristics of arbuscular mycorrhizal fungal (AMF) community structure in various soil depths and growing seasons of watermelon (Citrullus vulgaris) grown in commercial greenhouses in Daxing of Beijing and Weifang and Laiyang of Shandong, China were investigated using both morphological identification and denaturing gradient gel electrophoresis. The sampled soils had been used for continuous greenhouse production of watermelon for 0, 5, 10, 15, or 20 years. Glomus claroideum was the dominant species in the greenhouse soils planted for 5, 10, and 15 years in Laiyang, while Glomus mosseae and Glomus etunicatum were dominant in the nearby open farmland soil. Sorenson's similarity index of AMF community composition ranged from 0.67 to 0.84 in the soils planted for 5 years, and from 0.29 to 0.33 for 20 years among the three locations. Spore abundance, species richness, and the Shannon index were highest near the soil surface (0-10 cm) and decreased with soil depth, and higher in June and October than in August and December. Canonical correspondence analysis showed that available P and the number of years that soil had been used for greenhouse production were the main factors contributing to the variance of AMF community composition. It was concluded that the community structure of AMF was mainly influenced by soil available P and planting time of watermelon as well as by soil depth and seasonal variation in the commercial greenhouse.

Influencing Factors and Product Toxicity of Anthracene Oxidation by Fungal Laccase

The transformation profiles of polycyclic aromatic hydrocarbons （PAHs） by pure laccases from Trametes versicolor and Pycnoporus sanguineus, and the optimal reaction conditions （acetonitrile concentration, pH, temperature and incubation time） were determined. Anthracene was the most transformable PAH by both laccases, followed by benzo[a]pyrene, and benzo[a]anthracene. Laccase-mediator system （LMS） could not only improve the PAH oxidation but also extend the substrate types compared to laccase alone. 5e/0 or 10~ （v/v） of acetonitrile concentration, pH 4, temperature of 40 ~C, and incubation time of 24 h were most favorable for anthracene oxidation by laccase from T. versicolor or P. sanguineus. The gas chromatography-mass spectrometry analysis indicated that 9,10- anthraquinone was the main product of anthracene transformed by laccase from T. versicolor. Microtox test results showed that both anthracene and its laccase-transformation products were not acute toxic compounds, suggesting that laccase-treatment of anthracene would not increase the acute toxicity of contaminated site.