黄山松群落林隙光能效应与黄山松的更新

研究安徽黄山海拔１４００～１６００ｍ垂直带自草甸发育的黄山松林分的林隙,采用林隙周边树木年轮生长序列分析方法来推测林隙形成的时间,结果表明林隙形成与更新发生的时间基本相近。通过对林隙太阳辐射日变化的动态观测,建立了林隙中不同接受辐射总量及光合有效辐射与林冠空隙面积、扩展林隙面积、扩展林隙上方树冠郁闭状况的相关模型。结果表明,在观测时间段内,林隙中心点的总辐射量与光合有效辐射分别为全光照条件的９０％     

Phylogenetic and ecological structure of Mediterranean caddisfly communities at various spatio‐temporal scales

Aim The evolutionary processes structuring the composition of communities remain unclear due to the complexity of factors active at various spatial and temporal scales. Here, we conducted ecological and evolutionary analyses of communities of caddisflies in the genus Hydropsyche (Insecta: Trichoptera) composed of ecomorphologically differentiated species. Location River ecosystems in the Iberian Peninsula and northern Morocco. Methods Nineteen environmental variables were assessed at 180 local study sites and species presence/absence at these sites was used to determine their ecological niche. The evolutionary framework for all 19 species of Hydropsyche encountered was generated by phylogenetic analysis of the mitochondrial cytochrome c oxidase subunit I gene and three nuclear genes: wingless, elongation factor 1‐alpha and 28S RNA. The phylogenetic tree was used: (1) to assess evolutionary niche conservatism by ecological trait correlation with the tree; and (2) to analyse the phylogenetic relatedness of community member species, at three spatial scales (local stream reaches, drainage basins, biogeographical regions). Results Ecological measurements grouped most species into either headwater, mid‐stream or lowland specialists, and traits presumably relevant to river zonation were found to be phylogenetically conservative. Species assemblages at local stream reaches were mostly mono‐ or dispecific. Species diversity increased at larger spatial scales, by adding species with non‐overlapping ecological niches at the level of river basins and by turnover of anciently differentiated lineages at the level of biogeographical regions. This indicates the effects of competition and niche filtering on community structure locally, and ancient ecological diversification and allopatric speciation, respectively, in building up the species pool at basin and biogeographical scales. Main conclusions The study demonstrates the importance of scale (grain size) in studying what determines community composition. Current ecological factors (i.e. competitive exclusion) in Hydropsyche were evident only when studying narrow local sites, while studies of assemblages at larger spatial scales instead demonstrated the roles of ecological niche differentiation, phylogenetic history of trait diversification and allopatric speciation. Increasing the grain size of investigation reveals different portions of correlated spatial and evolutionary processes.     

植被对土壤微生物群落结构的影响

研究了不同土壤及覆盖其上的植被与土壤微生物群落结构和多样性的关系．植被使土壤中的微生物种类更丰富,群落多样性更高．表层土壤微生物群落中没有明显的优势种群,种间竞争作用较弱．并介绍了研究土壤微生物群落的分子生物学方法．     

清香型白酒固态酿造过程中酵母种群结构和多样性分析

【目的】探索清香型白酒固态酿造过程中酵母的种群结构和生态多样性变化规律,为科学认识白酒酿造的过程与机制提供理论依据。【方法】运用WL鉴别培养基和26S rRNA D1/D2序列分析方法对清香型白酒3种典型大曲和酒醅发酵过程的酵母进行分类学研究。【结果】从清香型白酒固态酿造过程中共鉴定出10种酵母,分别为Saccharomyces cerevisiae、Issatchenkia orientalis、Pichia anomala、Saccharomycopsis fibuligera、Pichia fermentans、Trichosporon asahii、Hanseniaspora osmophila、Pichia farinosa、Pichia membranifaciens和Clavispora lusitaniae。其中T.asahii、C.lusitaniae、H.osmophila、P.membranifaciens、P.farinose和P.fermentans为首次从清香型白酒酿造过程中分离获得的酵母种类。考察3种典型大曲(清茬、红心、后火曲)和大茬、二茬酒醅发酵过程的酵母种群结构变化规律显示,3种大曲具有相同的优势菌种S.fibuligera,但三者酵母结构组成差异较大,且清茬曲含有最多的酵母数量和种类。酒醅发酵过程中的酵母种群结构与3种大曲均明显不同,大茬和二茬酒醅酵母结构也不同,两种酒醅发酵后期的优势酵母均为S.cerevisiae,而发酵前期优势酵母则分别是H.osmophila和P.membranifaciens。【结论】深入研究了清香型白酒酿造过程中微生物的分布特征和规律,对认识清香型白酒酿造过程和群体微生物的发酵机制,以及丰富我国传统酿造食品微生物的研究,具有重要的理论和实践价值。     

Low community photosynthetic quotient in coral reef sediments

Fluxes of dissolved inorganic carbon and oxygen at the water-sediment interface were measured at eight coral reef stations (Indian Ocean) in summer and winter. The dark fluxes provided the community respiratory quotient (CRQ = dissolved inorganic carbon release / oxygen uptake) and the diurnal fluxes corrected from the dark fluxes gave the community photosynthetic quotient (CPQ = oxygen gross release / dissolved inorganic carbon gross uptake). The CRQ and the winter CPQ were not significantly different from 1. Summer CPQ (0.79; SD 0.02) was significantly lower than 1 due to the combined effect of the daily evolution of the community respiration and the discrepancy between the daily evolution in community oxygen respiration and community carbon respiration. These results highlight the importance of measuring simultaneously the benthic community production and respiration for long term integrated data sets, instead of the traditional daily or seasonal budget calculations from limited measures of community respiration. To cite this article: D. Taddei et al., C. R. Biologies 331 (2008).     

白僵菌生物防治林中虫生真菌群落结构分析

对白僵菌生物防治林中虫生真菌群落的结构研究表明,长期接种式释放白僵菌的马尾松林中虫生真菌共有属7种.球孢白僵菌的数量占绝对优势,为总数的63.22%;拟青霉次之,占25.86%;绿僵菌占9.20%;轮枝孢仅占1.72%.从寄主昆虫的多样性来看,球孢白僵菌和环链拟青霉的Brillouin多样性指数分别为3.56和2.315,均匀度分别为0.81和0.865;粉拟青霉和蜡蚧轮枝孢的多样性指数分别为1.71和0.862,均匀度为0.963和1.000而黄绿绿僵菌、金龟子绿僵菌和玫烟色拟青霉多样性和均匀度指标均较低.不同季节中被白僵菌侵染的寄主昆虫多样性指数呈现出春秋高、夏季低的趋势,反映了白僵菌种群的季节性变化.     

聚己二酸/对苯二甲酸丁二酯塑料地膜高效降解菌群筛选及其群落结构演替特征

【背景】以聚己二酸/对苯二甲酸丁二酯(PBAT)为主要成分的塑料地膜虽然是生物可降解的地膜,但是关于该塑料地膜降解的微生物菌群研究却较少。【目的】拟从不同环境样品中筛选可降解PBAT塑料地膜的微生物菌群。通过对其多次富集的菌群群落结构演替进行分析,明晰可降解PBAT塑料地膜的核心微生物。【方法】利用改良的SM无机盐培养基从不同环境样品中筛选可降解PBAT塑料地膜的微生物菌群;利用失重法测定菌群对PBAT塑料地膜降解的效率;利用16SrRNA基因高通量测序技术对其第5批次(G5)至第9批次(G9)富集的降解菌群的群落结构进行深入探讨;通过Pearson相关性分析方法对菌群不同菌属相对丰度变化和PBAT塑料地膜降解时间进行解析。【结果】从广州金发堆肥厂的堆肥样品中筛选到可完全降解PBAT塑料地膜的菌群,编号为SX。通过连续不断的转接富集,菌群SX对PBAT塑料地膜的降解速率显著提升。16SrRNA基因高通量测序结果显示第5批次(G5)至第9批次(G9)富集的PBAT塑料地膜降解菌群,厚壁菌门(Firmicutes)的相对丰度逐渐下降,而放线菌门(Actinobacteria)的相对丰度逐渐上升。硫磺色节杆菌(Arthrobactersulfureus)、红螺菌科(Rhodospirillaceae)和噬几丁质菌科(Chitinophagaceae)在随着转接富集过程中相对丰度逐渐升高而芽孢杆菌(Bacillussp.)的相对丰度显著降低。通过统计分析发现硫磺色节杆菌(Arthrobacter sulfureus)相对丰度升高与PBAT塑料地膜降解时间缩短显著相关(r=–0.927,P0.05)。【结论】筛选到PBAT塑料地膜高效降解菌群SX。通过连续不断的转接富集,菌群SX对PBAT塑料地膜的降解时间由28 d (第5批次,G5)降低到13 d (第9批次,G9)。通过对菌群群落结构的研究,发现随着菌群降解效率的提高,硫磺色节杆菌的所占相对丰度显著增加,说明其可能在PBAT塑料降解中发挥着关键作用。本研究为PBAT塑料地膜的降解提供了绿色高效环保的新途径和菌株资源,并为PBAT塑料地膜降解的机制研究奠定了基础。     

蓄水对三峡库区重庆段长江干流浮游植物群落结构的影响

为了分析三峡库区长江干流重庆段因蓄水产生的三类不同水体(自然河流型、过渡型、类湖泊型)对浮游植物的影响,分别于不同季节和蓄水期对水体浮游植物进行了群落调查,结果显示各群落指标仍呈现亚热带河流型水库的季节变化趋势:春季绿藻、隐藻占优势,夏季蓝藻所占比例增加,冬季硅藻占绝对优势,但不同类型水体对季节的响应程度不同:(1)2010年3月春季调查期间绿藻的优势种的优势度以及所占比例均呈现随水体类型改变逐渐增加趋势,并在类湖泊型水体中达到最大(优势度0.62、所占比例达67.8%),而夏秋季(9月蓄水前)蓝藻的优势种数、优势度、藻密度以及所占比例也存在同样的变化,2009年9月蓝藻所占比例由河流型水体的8.5%增加到类湖泊型水体的52.6%,到2010年9月类湖泊型水体蓝藻比例甚至达到63.8%。冬季蓄水期间(2010年1月),硅藻占绝对优势,但绿藻在类湖泊型水体中的比例要大于其他两类型水体。(2)Shannon-Wiener指数平均值为2.43,总体呈现出河流型水体>过渡型水体>类湖泊型水体,类湖泊型水体多样性指数夏秋季>冬季>春季,而自然河流型和过渡型水体冬季多样性指数低于其他季节。