Strong functional stability of soil microbial communities under semiarid Mediterranean conditions and subjected to long-term shifts in baseline precipitation     

《Soil biology & biochemistry》2014

We investigated the effect of soil microclimate on the structure and functioning of soil microbial communities in a Mediterranean Holm-oak forest subjected to 10 years of partial rain exclusion manipulations, simulating average drought conditions expected in Mediterranean areas for the following decades. We applied a high throughput DNA pyrosequencing technique coupled to parallel measurements of microbial respiration (R_H) and temperature sensitivity of microbial respiration (Q₁₀). Some consistent changes in the structure of bacterial communities suggest a slow process of community shifts parallel to the trend towards oligotrophy in response to long-term droughts. However, the structure of bacterial communities was mainly determined by short-term environmental fluctuations associated with sampling date (winter, spring and summer) rather than long-term (10 years) shifts in baseline precipitation. Moreover, long-term drought did not exert any chronic effect on the functioning of soil microbial communities (R_H and Q₁₀), emphasizing the functional stability of these communities to this long-term but mild shifts in water availability. We hypothesize that the particular conditions of the Mediterranean climate with strong seasonal shifts in both temperature and soil water availability but also characterized by very extreme environmental conditions during summer, was acting as a strong force in community assembling, selecting phenotypes adapted to the semiarid conditions characterizing Mediterranean ecosystems. Relations of climate with the phylogenetic structure and overall diversity of the communities as well as the distribution of the individual responses of different lineages (genera) to climate confirmed our hypotheses, evidencing communities dominated by thermotolerant and drought-tolerant phenotypes.  相似文献   

猪胆囊中沙门菌L型的分离培养与invA基因检测     

佘晓玲  王涛  丁文静  吴文娟  潘耀振  汤可立  王丹霓  王和 《动物医学进展》2015,(3):25-28

为了解猪胆囊中沙门菌L型携带情况,在贵阳市屠宰场采集970例健康生猪的胆囊组织与胆汁标本,用常规细菌学方法和非高渗分离培养法分离沙门菌及其细菌L型,用PCR和核酸序列分析方法对稳定L型纯培养物进行沙门菌的invA基因检测。结果显示,970例生猪胆囊标本未检出沙门菌细菌型,细菌L型检出率为8.25%;80例细菌L型分离物中有50例invA检测阳性,占5.15%;占细菌L型阳性分离物62.50%。研究结果为生猪胆囊沙门菌L型感染的流行病学及其检查提供了依据。  相似文献   

Associations of fish with various types of littoral habitats in reservoirs     

Marek Šmejkal  Marie Prchalová  Martin Čech  Mojmír Vašek  Milan Říha  Tomáš Jůza  Petr Blabolil  Jan Kubečka 《Ecology of Freshwater Fish》2014,23(3):405-413

Fish associations with different types of littoral habitats were studied in four canyon‐shaped reservoirs in the Czech Republic in years 2010 and 2011 by gillnets. Two to three habitats per reservoir–beaches (former meadows), stump fields (former forest) and rubble slopes–were defined and sampled along the longitudinal axis of reservoirs. Effects of reservoir, habitat and locality (position along longitudinal axis) on fish biomass, abundance and species structure were tested for juvenile and adult fish separately. Hierarchical analysis of variance revealed that habitats differed significantly in fish biomass and abundance. Redundancy analysis showed that analysed environmental variables had significant influence on fish community structure. Most variability in community structure was explained by reservoir and then by combination of habitat and slope steepness. Locality position had the smallest influence on community structure. For both adult and juvenile fish total abundance and biomass, the most inhabited habitat was beaches; rubble slopes were the least inhabited. Habitat associations differed among species. Among adults, bream Abramis brama, white bream Blicca bjoerkna and roach Rutilus rutilus were associated with beaches and stump fields, whereas perch Perca fluviatilis, ruffe Gymnocephalus cernuus, asp Aspius aspius and pike Esox lucius were associated with rubble slopes. Bream, white bream, bleak Alburnus alburnus, roach, ruffe and pikeperch Sander lucioperca were associated with beaches among juveniles, whereas the only juvenile associated with rubble slopes was perch. We showed that most common species are associated with distinct habitats and also that utilisation of various littoral habitats differs in general.  相似文献   

基于LEED-ND认证的绿色社区开发策略分析--以上海城市最佳实践区为例     

夏朝阳 《绿色科技》2020,(6):242-245

指出了中国正处在快速城市化的阶段,绿色社区开发已成为广泛关注的议题。以上海城市最佳实践区为例,通过对LEED-ND认证指标体系的分析,探讨了在LEED-ND认证体系驱动下,城市最佳实践区在场地规划、建筑节能、可再生能源和水资源利用等方面采取的开发策略和应用的绿色技术,以期为未来绿色社区的开发建设提供参考。  相似文献   

极小种群野生植物八蕊单室茱萸的种群状况研究     

张珊珊  袁春明  陈剑  张永坤 《林业调查规划》2020,45(2):82-87

八蕊单室茱萸为云南省特有的极小种群野生植物和濒危物种。通过查阅相关文献并结合访问调查,确定八蕊单室茱萸可能分布的区域,开展种群资源调查。结果显示:八蕊单室茱萸目前仅在普洱市和西双版纳州有10个天然种群,其种群规模已低于最小可存活种群,属极小种群野生植物和濒危物种,亟需开展保护工作。生境破坏和生境片段化是导致八蕊单室茱单室茱萸濒危的人为因素。提出收集种质资源、营建和管护近地保护种群、建立迁地和回归种群等保育建议。  相似文献   

High night-time temperature during flowering and pod filling affects flower opening,yield and seed fatty acid composition in canola     

Meghnath Pokharel  Anuj Chiluwal  Michael Stamm  Doohong Min  Davina Rhodes  S.V. Krishna Jagadish 《Journal of Agronomy and Crop Science》2020,206(5):579-596

Winter canola (Brassica napus L.) is highly sensitive to increasing temperatures during the reproductive and pod-filling stages. Although the impact of high day-time temperature stress on yield and quality has been documented in canola, similar information under high night-time temperature (HNT) stress is not available. Using six hybrids and four open-pollinated cultivars, we observed a marked shift in peak flowering towards earlier, cooler hours of the morning under HNT. Averaged across two independent experiments, the photochemical efficiency of photosystem II was significantly decreased (3%), with a significant increase in thylakoid membrane damage (13%) in the leaves of susceptible cultivars under HNT stress. Similarly, the susceptible cultivars also recorded significant reduction in biomass (34%), pod number (22%), pod weight (37%) and total seed weight (40%) per plant while the same set of agronomic traits were not affected among the tolerant cultivars. Quantitative impact of heat stress was confirmed with increased sensitivity to HNT exposure from gametogenesis until maturity resulting in a significantly higher yield loss compared to stress exposure from post-flowering till maturity. HNT significantly decreased oil concentration, but increased protein concentration and saturated fatty acid levels in seeds of the susceptible cultivars. However, HNT had no impact on the unsaturated fatty acids in both hybrids and the open-pollinated cultivars. Breeding targets based on fatty acid composition for enhancing canola seed quality may not be easily amenable due to the inconsistency documented with the compositional changes under heat stress. In summary, our findings conclude that canola hybrids are better suited to regions experiencing heat stress, compared to open-pollinated cultivars, indicating the possibility of a complete shift to hybrid canola cultivation under predicted hotter climates in the future.  相似文献   

浅谈大兴区社区蔬菜技术服务     

王维 《蔬菜》2020,(6):78-80

为提升社区居民的生活满意度,进一步探索阳台蔬菜管理技术、种植品种和管理模式,大兴区蔬菜技术推广站开展了基层调研、专业方案设计、观摩培训等社区蔬菜技术服务工作,并取得了较好的效果:服务范围不断扩大、栽培设备及配套技术逐渐完善、社区氛围良好等;并对发展前景进行了展望:未来将会向省空间、智能化、低碳化的多功能蔬菜种植模式发展。  相似文献   

不同药肥对香瓜土壤线虫群落的影响     

李涛  张龙  曾宇  李相煌 《热带作物学报》2016,36(10):46-49

通过施用不同药肥，研究其对香瓜根际线虫数量、土壤线虫群落的影响。结果表明，阿维?噻唑磷颗粒剂、复合芽孢杆菌水剂＋氨基酸、复合芽孢杆菌水剂、石灰氮、木霉菌能降低盆栽香瓜根际土壤线虫总数、植物寄生性、杂食性线虫、食真菌类线虫、捕食类线虫，其中对杂食性线虫的影响最大。从不同药肥处理对根结线虫数量的影响和防效来看，复合芽孢杆＋氨基酸处理和阿维?噻唑磷、石灰氮处理均取得不错的防治效果，平均防治效果为58.34%～100%，但三者之间差异不显著。从农产品质量安全和生态安全的角度出发，复合芽孢杆＋氨基酸具有更广阔的应用  相似文献   

西藏查吾拉地区不同性别牦牛产肉性能和肉营养成分的比较     

张强  达娃央拉  姬秋梅  信金伟  张成福  朱勇  洛桑顿珠  次旦央吉  孙光明  姜辉 《草业学报》2020,29(7):193-198

为了研究性别对查吾拉地区牦牛的产肉性能及肉营养成分的影响,随机选取8岁健康的查吾拉牦牛10头,公母各半,对不同组别间牦牛进行屠宰试验比较肉营养品质的差异。结果表明,母牦牛屠宰率、净肉率、胴体率、骨肉比均高于公牦牛,但无统计学差异。肉营养成分分析结果显示,母牦牛肉中维生素A、E、B₁₂、半胱氨酸、组氨酸、精氨酸、钙、硒、脂肪酸含量高于公牦牛(P<0.05)。研究结果表明,查吾拉牦牛富含较高的营养成分,可为人类提供优质健康的动物蛋白,具备作为优质牦牛肉源生产的潜力。相比较,母牦牛肉优于公牦牛。  相似文献   

中草药免疫活性物质对鱼类肠道菌群群落的影响研究进展     

林善婷  郑尧  胡庚东  裘丽萍  邴旭文  陈家长 《安徽农业科学》2017,45(32):94-98

对近年来国内外有关中草药免疫活性物质对鱼类肠道菌群群落结构的影响进行了综述,旨在为开发绿色高效、营养全面的饲料提供科学的理论依据。  相似文献