转Bt基因抗虫棉叶面可培养微生物多样性的变化

在大田栽培条件下,以转Bt基因抗虫棉GK-12和常规棉泗棉3号为材料,在棉花的苗期、现蕾期、花铃期和吐絮期分别测定棉花叶面细菌、真菌和放线菌的数量变化,并在花铃期和吐絮期对叶面细菌生理群的数量和多样性进行分析.结果表明：棉花叶面可培养微生物数量与其生长发育呈正相关,叶面可培养微生物的数量一般由苗期开始增多,到花铃期达最高峰,吐絮期明显减少;花铃期转Bt基因抗虫棉叶面细菌生理群Simpson指数、Shannon-Wiener指数和均匀度比常规棉升高,吐絮期比常规棉下降.     

野火病发病程度对叶面细菌群落多样性及基因功能的影响

为探究野火病发病程度对作物叶面细菌群落多样性和基因功能的影响,利用16S rRNA基因高通量测序技术,解析了野火病不同发病程度之间植株叶面细菌群落的组成和多样性差异,并通过PICRUSt工具预测了叶面细菌群落的基因功能。分析结果表明,随着野火病病情加重,叶面细菌群落的物种丰富度和多样性显著降低(P<0.01),叶面细菌群落的组成发生了显著改变(P<0.05);相应地,水培液中pH上升、总磷含量降低、速效钾含量先增加再降低。此外,植物叶面细菌群落的免疫系统疾病、信号分子和相互作用、外源性生物降解与代谢的相关性随着疾病严重加剧而减弱。综上所述,感野火病植株叶面细菌群落的结构和功能与病害程度密切相关,降低水培液中pH、提高总磷和速效钾含量可缓解野火病发病程度。     

食细菌线虫对土壤微生物量和微生物群落结构的影响

线虫与微生物的相互作用研究往往是在悉生培养体系 (gnotobiotic microcosm)中进行 ,为了研究在自然或开放土壤条件下土壤线虫与微生物的相互作用 ,作者在开放盆栽体系中接种土壤食细菌线虫 (原小杆线虫 ,Protorhabditis sp) ,研究在小麦不同生育期、在有和无根系作用下食细菌线虫对土壤微生物量和微生物群落结构的影响。结果表明 :接种线虫分别使 SMBC、SMBN、SMBP提高了 2 6 .4 %、32 .9%、2 1.8% ,这种促进作用除个别无根系土和非根际土处理外 ,均达到显著性差异。根际土中的 SMBC、SMBN、SMBP>非根际土 >无根系土。从方差解释比例 v来看 ,SMBN受线虫的影响最大 (v=2 4 % )、其次是 SMBC(v=16 % )、然后是 SMBP(v=12 % ) ,线虫对 SMBC的促进作用在根际土中最突出。接种线虫对土壤细菌、真菌和放线菌的数量有明显的影响。在苗期的无根系土和根际土中 ,接种线虫显著降低了细菌的数量、特别在根际土中尤为突出 ,但在其它处理中却增加了细菌的数量。接种线虫对真菌和放线菌数量的促进作用比对细菌更为明显 ,接种线虫后真菌和放线菌数量的总平均值分别比未接种提高了 4 8.5 %和 6 8.2 % ,而细菌数量的总平均值没有变化。细菌数量与微生物量 C相关散点图表明二者相关性在根际土、非根际土和无根系土中均未     

油藏微生物群落研究的方法学

油藏微生物群落的解析和认知是开发和应用微生物采油技术的基础。利用各种提高油藏微生物可培养性的方法和非培养技术解析不同油藏微生物的群落结构、功能和多样性,对定向调控油藏微生物群落、开发和应用有效微生物驱油技术具有重要的指导意义。通过调查新近发展的提高微生物可培养性的方法和措施以及不依赖于培养的分子微生物生态学技术,总结了油藏微生物群落研究方法学的最新进展。提高微生物可培养性的方法和措施主要通过模拟微生物的生存环境,减少富营养的毒害作用、添加信号分子维持微生物细胞间的作用和提供新型电子供体和受体等手段采用稀释法、高通量培养法等方法得以实现;不依赖于培养的分子微生物生态学技术主要包括荧光原位杂交、末端限制性片断长度多态性分析、变性梯度凝胶电泳和构建克隆文库等技术。这些方法学的进展为更有效的获得各种油藏微生物资源、调控油藏微生物群落以提高石油采收率提供理论指导。     

环丙沙星对土壤微生物量碳和土壤微生物 群落碳代谢多样性的影响

采用氯仿熏蒸浸提法和Biolog法,分析环丙沙星作用下的土壤微生物量碳和微生物群落碳代谢多样性,以揭示环丙沙星在环境中残留对土壤微生物学性状的影响.结果表明,环丙沙星(wCIP≥0.1 μg/g)对土壤微生物量碳含量影响显著(P＜0.05),土壤中环丙沙星浓度愈高,微生物量碳含量愈低,100μg/g的环丙沙星处理使土壤微生物量碳含量下降58.69％.环丙沙星对土壤微生物群落碳代谢功能影响显著,环丙沙星降低了土壤微生物对碳水化合物、羧酸、氨基酸、聚合物、酚类和胺类的碳源利用率;环丙沙星(wCIP≥0.1 μg/g)显著影响了土壤微生物群落碳源代谢强度和代谢多样性,但不同浓度的环丙沙星对土壤微生物群落碳代谢功能的影响不同,0.1、1、10 μg/g的环丙沙星处理对土壤微生物群落碳代谢功能的影响主要表现在处理前期(用药第7天、21天),这种影响在处理后期(用药第35天)表现不明显,100μg/g的环丙沙星在用药的前期和后期均显著影响土壤微生物群落碳代谢功能,土壤中环丙沙星积累到该浓度可能对土壤微生物群落碳代谢功能产生难以逆转的长期影响.     

油藏微生物群落结构解析

微生物采油(Microbial enhanced oil recovery,MEOR)以其费用低廉、无环境污染、施工简单、应用范围广等优点得到学者以及油田开发者的认同。油藏中的微生物类型多样且功能各异,可促进原油的开采,大幅度提高油气资源的利用率。因此分析油藏中微生物的类型和组成,了解土     

中国喀斯特地区微生物群落结构和功能的研究进展

频繁的人类生产活动使植被遭到破坏,造成基岩裸露的石漠化现象,严重制约了喀斯特地区自然和社会经济的发展,随着生态修复工程的大力开展,微生物群落的结构和功能在生态修复中逐渐受到重视,因为微生物作为喀斯特生态系统的重要组成部分,不仅在物质循环过程中起着重要作用,也在喀斯特生态系统修复中占有十分重要的地位。所以微生物群落结构和功能的研究可以作为衡量生态系统稳定性的重要指标。就中国喀斯特地区的典型植被恢复的不同阶段、成土过程、不同的土地利用方式、矿山修复过程以及不同水域中的微生物群落结构及功能等方面的研究状况进行系统梳理,结合实例综合论述喀斯特地区生态修复过程中微生物作用的研究进展,以期为喀斯特地区生态修复提供参考。     

土壤微生物群落抵抗力和恢复力研究进展

人类活动的不断加剧使得土壤生态系统承受着环境干扰压力。土壤微生物受到环境干扰的响应程度（抵抗力）及恢复至原来状态的能力（恢复力）决定着土壤生态系统的可持续性。梳理和总结了土壤微生物群落对环境干扰的抵抗力和恢复力方面的研究进展。首先,在介绍土壤微生物群落抵抗力和恢复力概念的基础上,阐述了通过评估微生物群落的结构和功能的变化来系统表征抵抗力和恢复力;随后,分析了最近十年（2012-2021年）有关文献,发现土壤微生物群落的结构和（或）功能在环境干扰后的恢复力总体较弱,但耕作、有机物料添加和轮作等农田管理措施下的响应趋势表现出一定的规律性;继而,从个体水平的休眠和胁迫忍耐、种群水平的生存策略、群落水平的多样性和相互作用以及生态系统水平的历史遗留效应等方面分析了土壤微生物群落抵抗力和恢复力的维持机制;最后,从功能性状、多功能性和植物-土壤微生物整体性对未来研究做出了展望,以期为构建土壤健康评价体系及预测环境干扰对土壤功能的影响提供科学依据。     

微生物群落结构和多样性研究

当前,由于基因组研究技术的发展,微生物学作为生命科学的一门经典学科面临着学科大发展的历史机遇.权威的美国<科学>杂志在2005年年底的1期杂志中预测,微生物学将是2006年有可能取得重要进展的科学领域之一.该杂志表示,随着从诸如土壤、人肠道黏膜这样的复杂样品中提取DNA方法的优化,微生物的难以置信的多样性正在逐渐被人们所认识.2006年,将有大量的有关论文发表,内容将涉及微生物群落进化和分子机制、各种有益或致病性的微生物与其宿主间的关系、微生物种间横向基因转移的细节,甚至有可能形成1个统一的微生物进化树,并对真核细胞产生的过程有更加清晰的认识[链接1].事实上,2006年新年伊始,就有一批有关论文在权威杂志发表.     

洞庭湖典型湿地植被群落土壤微生物特征

以洞庭湖湿地3种典型植被(虉草、苔草、芦苇)为对象,研究了不同植被下土壤微生物生物量和微生物呼吸等特征,并对其主要影响因子进行了分析.结果表明:微生物生物量碳、氮和微生物呼吸以虉草群落最高,苔草群落次之,芦苇群落最低,微生物碳熵变化趋势为虉草群落＞苔草群落＞芦苇群落,微生物呼吸熵具有与微生物碳熵相反的变化趋势.相关分析表明:土壤含水量、容重和有机质是影响土壤微生物特征变化的重要因子,同时,土壤pH和土壤总氮与土壤微生物生物量碳、微生物生物量氮、微生物呼吸等也有较强的关联性.     

Fungal biomass associated with the phyllosphere of bryophytes and vascular plants

Little is known about the amount of fungal biomass in the phyllosphere of bryophytes compared to higher plants. In this study, fungal biomass associated with the phyllosphere of three bryophytes (Hylocomium splendens, Pleurozium schreberi, Polytrichum commune) and three vascular plants (Avenella flexuosa, Gymnocarpium dryopteris, Vaccinium myrtillus) was investigated using ergosterol content as a proxy for fungal biomass. Phyllosphere fungi accounted for 0.2-4.0 % of the dry mass of moss gametophytes, representing the first estimation of fungal biomass associated with bryophytes. Significantly more fungal biomass was associated with the phyllosphere of bryophytes than co-occurring vascular plants. The ergosterol present in moss gametophytic tissues differed significantly between species, while the ergosterol present in vascular plant leaf tissues did not. The photosynthetic tissues of mosses had less associated fungal biomass than their senescent tissues, and the magnitude of this difference varied in a species-specific manner. The fungal biomass associated with the vascular plants studied varied significantly between localities, while that of mosses did not. The observed differences in phyllosphere community biomass suggest their size could be affected by host anatomical and physiological attributes, including micro-niche availability and chemical host defenses, in addition to abiotic factors like moisture and nutrient availability.     

Plant–animal associations in two species of seagrasses in Western Australia

Relationships between algal epiphytes and epifaunal invertebrates (amphipods, molluscs and polychaetes) occurring within meadows of the seagrasses Posidonia sinuosa and Amphibolis griffithii were compared along the south west coast of Western Australia. Although the seagrasses are very different structurally, many species of algal epiphytes and epifaunal grazers were common to both. However, meadows of Amphibolis supported a greater number of both algal epiphyte and epifaunal species. The long-lived stems of Amphibolis supported a larger biomass of algal epiphytes and grazers than did the leaves of either Posidonia or Amphibolis. The densities and biomass of epifauna were variable but on a comparison adjusted to the biomass of seagrass, both the density and biomass of the taxonomic groups were similar between seagrass species except that the density of grazing gastropods and the biomass of polychaetes were greater in Amphibolis (by 238% and 252%, respectively). Nested analyses of variance (ANOVA) indicated that variations in plant and animal biomass differed at all spatial scales (sites, meadows within sites and replicates) and the pattern was inconsistent amongst biota. However, a significant proportion of the variability occurred between replicate samples. Canonical correlation and multiple regression analyses indicated that associations between algal epiphytes and epifauna were also inconsistent and differed between seagrass species. These patterns highlight the importance of seagrass species and structural complexity in affecting both the epiphytic and grazer community. The importance of spatial scales at which seagrasses and their associated communities are sampled are equally important because of the differing levels of spatial patchiness.     

Aphid honeydew and its effect on the phyllosphere microflora of Picea abies (L.) Karst

Aphids of the genus Cinara, feeding on Norway spruce, excrete copious amounts of honeydew, a carbon-rich waste product, which accumulates locally on needles and twigs. We investigated the role of honeydew as a potential source of energy which might promote the growth of micro-organisms in the phyllosphere of conifer trees. To approach this question, we followed the population dynamics of Cinara spp. in a natural forest stand over two seasons. We also studied the amounts of honeydew produced by individual aphids and identified potential parameters which might influence honeydew production. Finally, we determined the growth of micro-organisms on infested and uninfested needles of Norway spruce during the growing season. Confined to Picea abies, the investigated Cinara species only became abundant in midsummer, when needles and shoots were expanding. The populations showed only a single peak in abundance, the timing and magnitude of which may vary from year to year due to weather conditions, changes in plant quality in a yearly cycle or the impact of natural enemies. The amount of honeydew produced by individual aphids was dependent on the developmental stage of the aphid, the nutritional supply of its host plant and on the developmental state of the Norway spruce (e.g. bud burst, end of shoot extension). The presence of honeydew significantly increased the growth of bacteria, yeast and filamentous fungi on the surface of needles and there was a pronounced seasonal trend, with the highest abundance in midsummer correlating with the period of peak aphid abundance. Taken together, these findings indicate that aphids have an influence on microbial ecology in the phyllosphere of trees. The implication of our study, from interactions at the population level to effects and potential consequences for C and N fluxes at the level of forest ecosystems, is discussed.     

Regional variation in eelgrass (Zostera marina) morphology, production and stable sulfur isotopic composition along the Baltic Sea and Skagerrak coasts

Morphology, total sulfur content and stable sulfur isotopic composition of Zostera marina were examined in the Baltic Sea–Skagerrak transition zone through surveys. The seagrass meadows were denser and less productive at the low salinities in the Baltic Sea (salinity 6–7 psu), and total sulfur accumulations in plants were lower and δ³⁴S values were higher compared to the west coast of Sweden (salinity 21–29 psu). The δ³⁴S values of the three plant compartments (leaves, rhizomes, roots) indicated lower sulfide invasion at low salinities, which was mainly due to environmental conditions (e.g. low epiphytic biomass, low sediment organic matter and low sulfate concentration) and plant characteristics (productivity, shoot morphology). Between 13% and 63% of the sulfur in the plants was derived from sediment sulfides with highest percentages in the roots (27–63%) and lower in rhizomes (13–50%) and leaves (14–51%). The high sulfide invasion on the west coast of Sweden was coincident with high sediment organic matter, probably increasing sulfide pressure on the plants, and high epiphytic biomass, probably constraining the oxygen dynamics in the plants and enhancing sulfide invasion. Regional and spatial variability in the δ³⁴S were extensive, emphasizing the need for detailed analysis of local sources when applying stable sulfur isotopes in food web analyses. The observed invasion of sulfides suggests sulfide as a contributing factor to reported declines of Z. marina in the Skagerrak region.     

Tree species shape the elemental composition in the lichen Hypogymnia physodes transplanted to pairs of spruce and beech trunks

The lichen Hypogymnia physodes was sampled from spruce trunks and we used to assess natural elements in the throughfall from pairs of neighbouring beech (Fagus sylvatica) and spruce (Picea abies) canopies in an unmanaged forest reserve. The beech bark (pH = 4.36 ± 0.13) was less acidic than spruce bark (3.71 ± 0.06). After a 1 yr transplantation onto trunks, lichens on beech had significantly higher concentrations of Ca, K, Mg and P than on spruce, and lower Mn, Zn and C, but had similar Al, B, Fe, N, Na, S and Si concentrations. Base cations (Ca, Mg, K) in lichens highly significantly increased with bark pH, with no overlap between tree species neither for base cations, nor for pH. The results are consistent with the view that trees modify the elemental composition of lichens in their dripzone, and that trees at least to some extent can modify the elemental chemistry of their local surroundings and thus influence ecosystem processes. We discuss lichen transplantation as a method to estimate long-term effects of tree species on local chemical environments.     

Mass cultivation of seaweeds: current aspects and approaches

A word-wide overview is presented of the current state of mass cultivation of seaweeds. In comparison with a total annual commercial production of fish, crustaceans and molluscs of about 120 × 10⁶t, of which one-third is produced by aquaculture, the production of seaweeds is about 10 × 10⁶t wet weight; the majoirty of this comes from culture-based systems. The Top Ten Species List is headed by the kelp Laminaria japonica with 4.2 × 10⁶t fresh weight cultivated mainly in China. The productivity of a well-developed, multi-layered, perennial seaweed vegetation is as high as dense terrestrial vegetation, and even higher annual values for productivity have been reported for tank cultures of macroalgae. Epiphytes provide a major problem for the seaweed cultivator, but can be controlled by growing plants at high densities in rope cultures in the sea, or, more easily, in seaweed tank cultures on land. The main environmental problem of animal (fed) aquaculture is the discharge of nutrient loads into coastal waters, e.g., 35 kg N and 7 kg P t^–1 aquacultured fish. Integration of fish and seaweed farming may help to solve this problem, since seaweeds can remove up to 90% of the nutrient discharge from an intensive fish farm. Mass culture of commercially valuable seaweed species is likely to play an increasingly important role as a nutrient-removal system to alleviate eutrophication problems due to fed aquaculture.     

附生植物生理生态适应性研究进展

附生植物是生活在其它植物体或残体上的特殊植物类群,大多生长于森林冠层,空间上远离地面土壤,在光能、水分和养分吸收方面具有明显的局限性。对附生植物的类群、分布、生态功能及对环境的适应性进行了综述,着重分析了附生植物在环境资源有限的生境中生长旺盛并占据重要生态位的原因。同时对今后的研究方向进行了展望,即更新附生植物数据库,明确附生植物水分和养分来源及利用策略,加强对附生植物开发利用及资源恢复重建的研究。     

Phyllosphere and rhizosphere microflora of pearl millet with reference to downy mildew incited bySclerospora graminicola (Sacc.) Schroet

Summary Analysis of phyllosphere microflora showed that in the resistant cultivar (PHB-14) there was a significantly higher population of fungi, gram positive and gram negative bacteria, compared to susceptible cultivar (NHB-3) under healthy and diseased situations. The cultivars during earhead stage supported maximum phyllosphere fungal and gram negative bacterial populations.The rhizosphere of the susceptible cultivar under downy mildew influence supported maximum fungal and gram negative bacterial populations and the rhizosphere effect was the highest in downy mildew colonized susceptible NHB-3 at the earhead stage (95 days after planting).Among the fungi isolated Cladosporium dominated the phyllosphere of resistant, susceptible and susceptible cultivar under the influence of downy mildew.Among the rhizosphere microflora the population ofAspergillus sp. was found to be greatest in resistant, susceptible and the susceptible cultivar under the influence of downy mildew.