桂江流域附生硅藻群落特征及影响因素

研究了桂江流域水质、土地利用、地理因素对河流附生硅藻群落的影响。结果显示,桂江流域电导率(Conductivity,Cond.)由下游至源头呈降低趋势,其它水质参数变化趋势不明显。主成分分析(Principle Component Analysis,PCA)显示前两个主成分共解释了56.2%的水质特征,第一轴反映了氨氮(NH4-N)、硝氮(NO3-N)、总氮(Total Nitrogen,TN)的变化梯度,第二轴反映了水温(WT)、pH、Cond.、溶解氧(Dissolve Oxygen,DO)的变化梯度。桂江流域硅藻特定污染敏感指数(Specific PolluoSensitivity Index,IPS)和硅藻生物指数(Biological Diatom Index,IBD)下游低于源头,差异不显著,与多项水质、土地利用以及地理因子呈线性显著相关。24个样地共发现112种硅藻,丰富度大于5%的37种,丰富度最大的几个种类依次为Achnanthidium minutissimum,A.pusilla,A.tropica,Cymbella laevis。对应分析(Corresponding Analysis,CA)显示桂江流域存在3个差异较大的硅藻群落,流域下游以Nitzschia recta为优势种,A.lanceolata、Amphora montan、Planothidium frequentissimum在中下游丰度较高,上游区域种类较多。典型相关分析(Canonical Correspondence Analysis,CCA)排序前两轴解释了硅藻群落变异程度的28.60%,CCA排序轴1与水质(Cond.、WT、NH4-N、NO3-N、TN)和土地利用(城市面积、农田面积、植被覆盖)显著负相关,与地理因素(流域面积、海拔、坡度)显著正相关,第二轴与浊度(NTU)显著正相关(P<0.05)。偏典型相关分析(Partial CCAAnalyses)显示,土地利用、地理因子、水质分别解释了桂江流域硅藻群落变异的7.20%,17.50%,48.50%。结果表明,桂江流域附生硅藻群落结构是水质、地理因子和土地利用共同作用的结果,水质起决定性作用,电导和不同形态的氮是影响附生硅藻群落结构的主要水质因素。     

七项河流附着硅藻指数在东江的适用性评估

综合运用因子分析、聚类分析、箱型图分析等统计方法评估了河流附着硅藻生物指数(Biological Diatom Index,IBD)、硅藻营养化指数(Trophic Diatom Index,TDI)、斯雷德切克指数(Sládecˇek’s Index,SLA)、特定污染敏感指数(Specific Polluosensitivity Index,IPS)、硅藻属指数(Generic Diatom Index,IDG)、戴斯指数(Descy Index,DESCY)和欧盟硅藻指数(European Economic Community Index,CEE)在东江流域河流水质评价中的适用性。结果显示:SLA与IPS,CEE显著相关(P<0.05),CEE与TDI不相关,其余指标间均极显著相关(P<0.01)。SLA与13项水质理化指标均无相关性,TDI与含氯度(Cl)显著负相关,CEE与溶解氧(DO)、电导率(Cond.)、总氮(TN)显著正相关(P<0.05),其余指标与氨氮(NH4-N)、pH不存在线性相关,与五日生化需氧量(BOD5)、高锰酸盐指数(CODKMnO4)、亚硝氮(NO2-N)、硝氮(NO3-N),总磷(TP)具极显著相关性(P<0.01)。13项水质理化指标中主成分负荷贡献大于50%的八项理化参数DO、BOD5、CODKMnO4、TN、NO3-N、NO2-N、TP和SiO2将试验区水质分为四组。IPS、IBD、IDG和CEE与水质物化分类一致性较好。IPS、IBD、IDG和CEE的逐步判别分析(引入P=0.20,剔除P=0.25)显示IPS和CEE都只选出了NO2-N,分类判别的正确率分别为55.6%和48.1%;IBD引入了NO2-N,CODKMnO4和DO 3个解释变量,判别正确率74.1%;IDG引入BOD5和NO3-N两个变量,分组正确率63.0%。硅藻群落聚类显示,IBD和IDG在水质物化分类的箱型图中呈现出明显合理的趋势。以上研究表明IBD和IDG硅藻指数最适合用于东江河流水质生物监测与评价。     

三峡库区古夫河着生藻类分布与水质因子的关系

于2010年12月至2011年12月,对位于长江三峡库区内的湖北省兴山县古夫河着生的藻类和水体共采样10次,共鉴定出着生藻类28属,检测水质指标12项。对水质变量进行因子分析,根据特征值大于1的原则选取4个主成分,第一主成分主要代表总氮（TN）和硝酸盐氮（NO3--N）,第二主成分主要代表pH和化学需氧量（CODCr）,第三主成分主要代表磷酸盐磷（PO34--P）、总磷（TP）和氨氮（NH4＋-N）,第四主成分主要代表电导率（Cond）和总有机碳（TOC）。将提取的9项主要水质因子与着生藻类重要属进行典型对应分析（CCA）,结果可见,古夫河主要水质因子与着生藻类类群分布相关性大小为：CODCr〉pH〉TN〉NO3--N〉TOC〉TP〉PO34--P〉Cond〉NH4＋-N。Monte Carlo显著性检验表明,CODCr和pH对古夫河着生藻类物种组成及空间分布的影响最大,其次为TN、NO3--N和TOC。pH与CODCr呈极强的负相关关系,古夫河着生藻类大多数类群均与CODCr表现出正相关关系,仅胶毛藻属（Chaetophora）倾向低CODcr和偏碱性的环境。TN和NO3--N有很强正相关性,而两者均与TOC有强负相关,它们将古夫河着生藻类大体上分为两类,即亲碳元素的类群和亲氮元素的类群。TP通常是河流生态系统中的限制性营养因子,但在古夫河流域中并不是影响着生藻类物种分布的主要水质因子。     

三峡水库库首初期蓄水前后理化因子的比较研究

根据2002—2004年对三峡水库库首的监测,对该水域的理化特征及其动态进行了比较分析,并对三峡水库初期蓄水前后的数据进行了差异显著性分析。结果显示主要理化指标空间差异不大,主要随季节变化。部分理化指标在蓄水前后有显著差异。其中TN、TP在蓄水后与蓄水前同期比较有明显降低,分别由蓄水前的周年平均值2.38mg/L、0.274mg/L下降到蓄水后的1.62mg/L0、.132mg/L。在无机氮组成中,NO3-N高达91.25%,而NO2-N仅占1.05%,这表明调查水域有较强的自净能力。透明度、浊度月变化很大,且呈良好的负相关,并在7—9月分别有显著降低与升高,表明本地区水土流失在降雨季节十分剧烈。而TP也随库区水体中悬浮物增高而显著增高,表明流失水土受磷污染严重。但由于同时期PO4-P反而是降低的,则说明此污染并不能有效转化为PO4-P。对营养状态指数(TSIM)的评价表明,尽管蓄水后库首水质污染较之蓄水前有明显降低,但仍呈中营养化水平。与国内其他大型水库比较,结果显示TP、NO3-N都远远高于被比较水库。     

密云水库水体营养状态分析

调研结果显示 ,密云水库的营养特征为浮游藻类响应型。浮游藻类的群落结构是绿藻 (Chlorophyta)—硅藻(Bacillariophyta)型。库区水体TN 0 86mg/L ,TP 0 .0 2 2mg/L ,浮游藻类的细胞密度 4 0 5 2 3× 10 4/L。 4项指标 (Tr、TP、CODmn、chla)的TSIM 值 4 0 1— 4 9 6 ,水体为中营养。但TN、TP和浮游藻类细胞密度增长较快 ,水体向富营养发展的趋势明显。主要制约因素是面源、点源和内源对水体的污染。北京市水资源紧缺 ,密云水库是主要饮用水源地。保护流域生态环境 ,治理污染 ,涵养水源 ,实现水资源的可持续利用已很迫切     

白洋淀硅藻分布及其与水环境的关系

记录了白洋淀不同水域发现的硅藻85个种、变种及未定种,隶属于22个科31个属,其中小环藻属(Cyclotella)、菱形藻属(Nitzschia)、美壁藻属(Caloneis)和舟形藻属(Navicula)等为优势类群。在白洋淀东北部景区水域,以梅尼小环藻(Cyclotellameneghiniana)为主;污染严重的入库河道水域,以半裸具席藻(Sellaphora seminulum)和蓝绿舟形藻(Navicula veneta)为代表;村落水域,以菱形藻属、舟形藻属硅藻为主;航道水域,以颗粒沟链藻(Aulacoseira granulata)为代表;荷塘以弯棒杆藻(Rhopalodia gibba)为代表;而鱼池以菱形藻属硅藻为主。典范对应分析(canonical correspondence analysis,CCA)显示水体总磷浓度(total phosphorus,TP)和pH是影响白洋淀硅藻种群分布的重要因素。利用欧洲硅藻数据库对白洋淀TP和pH做了定量重建,TP为0.13-0.25 mg/L,pH为6.92-7.23,此估测值极为接近实测值。     

三峡水库及香溪河库湾理化特征的比较研究

根据2003年6月三峡水库初期蓄水后对香溪河库湾的常规监测,对该水域的理化特征及其动态进行了分析,并与三峡水库库首的数据进行了比较研究。结果显示库湾TN、NO3-N浓度要显著低于库首,前者两周年平均值为1.29mg/L,0.88mg/L,后者两周年平均值为1.62mg/L,1.22mg/L。而PO4-P则是库湾显著高于库首,并且在7—9月库首的TP/PO4-P有显著提高。结果同时表明库首的水土流失较严重,而库湾则有较好的水土保持。最后对TSIM的计算结果表明,由于TP、TN都处于高水平,库首呈现中营养化(TSIM>37),而库湾则呈现严重富营养化(TSIM>53)。     

太湖流域典型入湖港口景观格局对河流水质的影响

以太湖流域宜兴段的3条主要入湖港口为研究对象,通过实地调查和数据分析,探讨了入湖港口景观格局对河流水质的影响。反映景观格局的指标有港口周边5 km缓冲区域内的"源-汇"景观空间负荷对比指数(LCI)、斑块数量(NP)、边界密度(ED)、蔓延度指数(CONT)、香浓多样性指数(SHDI)和聚集度指数(AI);反映水质变化的主要指标为总氮(TN)、总磷(TP)和化学需氧量(CODMn)。以水质指标为因变量,对二者做了相关性分析和通径分析,结果表明,LCI与TN、TP和CODMn关系显著,对它们的直接作用分别为0.266、1.512和0.979;ED对TN、CODMn和NH+4-N有显著影响,直接作用为0.740、-0.189和0.852;TN和NH+4-N与CONT相关性显著,与SHDI呈负的极显著相关;对TN和NH+4-N来说,两个景观格局指标(LCI与景观格局指数)对它们都呈直接负作用;其它指标之间关系不显著。这说明景观格局变化对区域内港口水质有一定影响,合理配置景观格局能够有效地治理面源污染,改善水质状况。     

大型溞引导的沉水植被生态修复对滴水湖水质的净化效果

2007年4月-2008年1月,在滴水湖D港中段长950m(水量为10000m3)的修复区内投放大型溞(Daphnia magna),以滤除水华藻类等颗粒有机物,然后移栽伊乐藻、苦草、轮叶黒藻、光叶眼子菜和菹草等沉水植物,逐月监测水体中总氮(TN)、铵态氮(NH4+-N)、硝态氮(NO3--N)、亚硝态氮(NO2--N)、总磷(TP)、活性磷酸盐(PO43--P)和COD等水质指标,分析沉水植被栽培对滴水湖水体水质的净化效果.结果表明:试验期间,修复区水体TN、TP、NO3--N、NO2--N、NH4+-N、PO43--P和COD显著低于对照区(P0.01),溶解氧(DO)增加了50.4%,水体透明度(SD)平均在3.4~3.7m,水质达到国家Ⅱ~Ⅲ类地表水水质标准;2008年3月应用已构建的沉水植被群落对富营养化流水水体水质进行净化试验,7d后修复区流水水体除BOD外,TN、TP、NO3--N、NO2--N、NH4+-N、PO43--P和COD均显著降低(P0.01),DO增加了17.98%,SD提高了30cm.利用大型溞控藻后移栽沉水植物对滴水湖水体水质的净化效果十分显著.     

柳江流域不同水文季节水质对附生硅藻群落的影响研究

为研究溶解氧(DO)、化学需氧量(CODMn)、氨氮(NH4+-N)、汞(Hg)、铅(Pb)、砷(As)和镉(Cd)在枯水期和丰水期变化对附生硅藻群落结构的影响, 分别于 2017 年 3 月和 6 月对柳江流域进行了调查分析, 旨在为深入研究柳江流域硅藻群落分布特征奠定基础, 以期为该流域水质的利用和管理提供理论依据。柳江流域共鉴定出附生硅藻 137 种, 隶属于 6 目 9 科 34 属。各采样点硅藻丰富度变化范围为 13-42 种, 呈现为丰水期高于枯水期。硅藻优势种组成在枯、丰水期分别有 5 种和 8 种, 具有明显的季节演替。聚类分析(Cluster analysis)显示, 硅藻群落结构在时空分布上存在差异, 枯水期可分为 3 个类群, 基本呈现在干流及支流段的上游、中游和下游; 丰水期可分为 2 个类群, 大致分布在流域的中下游和上游。其中, 在枯水期, Cyclotella fottii、Cyclotella. stelligera、Achnanthes minutissima 和 Cymbella laveis 在上游为优势种, A. minutissima 和 Nitzschia valdecostata 在中游丰度较高, 下游优势种为 Navicula cryptocephala、Amphora montana 和 A. minutissima 等; 在丰水期, 中下游优势种主要以 Nitzschia palea 为主, 上游优势种为 A. minutissima、A. montana 和 Achnanthes petersenii 等。主成分分析(Principle component analysis, PCA)和冗余分析(Redundancy analysis, RDA)显示, 枯水期水质因子对硅藻群落的影响为 Pb>Cd>Hg>As>CODMn>DO, 丰水期为 As>DO>CODMn>NH4+-N>Cd。结果表明, 水质因子 Cd、As、DO 和 CODMn 在枯水期和丰水期都对硅藻群落结构的变化起着重要作用, 但重金属因子在枯水期对硅藻影响较大, 而溶解氧在丰水期对硅藻影响较大。     

六种藓类植物茎的比较解剖学研究

通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.     

Photoregulation of seed germination of wild-type and of an aurea-mutant of tomato

Seed germination of an aurea mutant of tomato ( Lycopersicon esculentum Mill.) is promoted by continuous irradiation with red, far-red or long-wavelength far-red (758 nm) light as well as by cyclic irradiations (5 min red or 5 min far-red/25 min darkness). Far-red light applied immediately after each red does not change the germination behaviour. Seed germination of the isogenic wild-type, cv. UC-105, is promoted by continuous and cyclic red light while it is inhibited by continuous and cyclic far-red light and by continious 758 nm irradiation. Far-red irradiation reverses almost completely the promoting effect of red light. The promoting effect (in the aurea mutant) and the inhibitory effect (in the wild-type) of continuous far-red light do not show photon fluence rate dependency above 20 nmol m⁻² s⁻¹. It is concluded that phytochrome controls tomato seed germination throgh low energy responses in both the wild type and the au mutant. The promoting effect of continuous and cyclic far-red light in the au mutant can be attributed to a greater sensitivity to P_fr.     

真菌类遗传学分析的知识结构教学

本文以认知结构理论为指导,讨论了真菌类遗传分析与高等动植物遗传分析的内在联系,认为利用这种内在联系进行教学可收到好的效果并说明了作者的具体教学过程。 Abstract:In the paper, the relationship between genetic analysis of Fungi and genetic analysis of high animal and plant was discussed.A good results were obtained when we adopted this method in the teaching.     

Cause of Senescence of Nine Sorts of Flowers

The levels of endogenous phytohormones and respiratory rate in nine sorts of flowers such as Cymbidium faberi Rolfe, Nopalxochia ackermannii Kunth and others were investigated both at full bloom and senescence and meanwhile the effect of exogenous phytohormones on prolonging the blossoms and promoting ethylene production were tested. There is a high content of endogenous ethylene in all the long-lived flowere, about 3–16 folds higer than the short-lived ones. There is a high level of ABA at full blooming flowers of short-lived flowers, in which there is no or only some cytokinins in it, but the ratio of CTK (6BA+zeatin)/ABA is smaller(l.7). The endogenous ABA reached a much higher level at senescence in all nine sorts of flowers, so it is reasonable to consider that it is ABA which plays an important role of regulation in controlling flower's senescence. There is a much higher level of GA3 and zeatin in the long-lived flowers which is not demonstrated in the shortlived ones. The respiratory rate is one of the factors controtling the longevity of flowers, but it does not play a decided role. Application of 6BA and zeatin prolongs distinctly orchid’s longevity, however exogenous IAA through the promotive action on ethylene production, evidently extends the longevity of the flowers of the Nopalxochia ackermannii Kunth.     

Interconnection of parameters of regulation system of lipid peroxidation and of morphophysiological parameters of mouse liver

A complex analysis of seasonal fluctuations of the mean group parameters of the system of regulation of lipid peroxidation has been performed in liver of Balb/c mice. Association of lipid characteristics and morphophysiological parameters is studied in the Balb/c mouse liver. An inter-connection is revealed between the liver index and the amount of lysoforms of phospholipids, the scale and character of the interconnection differing essentially depending on proportion of phos-phatidylcholine in mouse liver phospholipids.     

龙胆科药用植物化学成分的研究现状

龙胆科植物在我国的分布范围很广,且多数为药用植物,其多数种属的药用植物,至今其化学成分尚未被系统研究。综述了目前龙胆科药用植物的化学成分的研究现状及一般提取方法,对近年来发现的环烯醚萜及裂环烯醚萜类化合物进行了总结,为本科药用植物的更深入研究提供了参考。     

Physiological characteristics of various species of strains of carboxydobacteria

Seven strains of aerobic carbon monoxide-oxidizing bacteria (carboxydebacteria) when growing on CO as sole source of carbon and energy had doubling times which ranged from 12–42 h. The activity profiles obtained after discontinuous sucrose density gradient centrifugation indicated that the CO-oxidizing enzymes are soluble and the hydrogenases are membrane-bound in all strains examined. The CO-oxidizing enzymes of Pseudomonas carboxydohydrogena, Pseudomonas carboxydoflava, Comamonas compransoris, and the so far unidentified strains OM2, OM3, and OM4 had a molecular weight of 230,000; that of Achromobacter carboxydus amounted to 170,000. The molecular weights of the CO-oxidizing and H₂-oxidizing enzymes turned out to be identical. The cell sonicates were shown to catalyze the oxidation of both CO and H₂ with methylene blue, thionine, phenazine methosulfate, toluylene blue, dichlorophenolindophenol, cytochrome c or ferricyanide as electron acceptors. Methyl viologen, benzyl viologen, FAD⁺, FMN⁺, and NAD(P)⁺ were not reduced. The spectrum of electron acceptors was identical for all strains tested. Neither free formate, hydrogen nor oxygen gas were involved in the CO-oxidation reaction. Methylene blue was reduced by CO at a 1:1 molar ratio. The results indicate that CO-oxidation by carboxydobacteria is catalyzed by identical or similar enzymes and that the reaction obeys the equation CO+H₂OCO₂+2H⁺+2e^- as previously shown for Pseudomonas carboxydovorans.Dedicated to Otto Kandler remembering almost three decades of enjoyable cooperation     

Modulation of allostery of pyruvate kinase by shifting of an ensemble of microstates

Since the introduction of the concepts of allostery about four decades ago, much advancement has been made in elucidating the structure-function correlation in allostery. However, there are still a number of issues that remain unresolved. In this review we used mammalian pyruvate kinase (PK) as a model system to understand the role of protein dynamics in modulating cooperativity. PK has a triosephosphate isomerase (TIM)(α/β)₈ barrel structural motif. PK is an ideal system to address basic questions regarding regulatory mechanisms about this common (α/β)₈ structural motif. The simplest model accounting for all of the solution thermodynamic and kinetic data on ligand-enzyme interactions involves two conformational states, inactive E^T and active E^R. These conformational states are represented by domain movements. Further studies provide the first evidence for a differential effect of ligand binding on the dynamics of the structural elements, not major secondary structural changes. These data are consistent with our model that allosteric regulation of PK is the consequence of perturbation of the distribution of an ensemble of states in which the inactive E^T and active E^R represent the two extreme end states. Sequence differences and ligands can modulate the distribution of states leading to alterations of functions. The future work includes: defining the network of functionally connected residues; elucidating the chemical principles governing the sequence differences which affect functions; and probing the nature of mutations on the stability of the secondary structural elements, which in turn modulate allostery.