山西临汾市郊土壤动物生态分布特征

为了解临汾市郊土壤动物群落多样性及其生态分布特征,2009年4～10月间对山西省临汾市郊7个类型生境中(林地、农田、果园、道路绿化带、汾河滩涂废弃地、重金属污染区农田及林地)的土壤动物群落进行了调查,采用手拣法和干漏斗法,共捕获土壤动物个体5 842只,隶属4门9纲25目。优势类群为弹尾目、蜱螨目和膜翅目,常见类群14种,稀有类群8种。结果显示,土壤动物个体数量因季节不同呈现出一定规律性,即秋季春季夏季。土壤动物垂直分布上,非污染区的1、2、3号样地表聚性明显,中度污染区的4、5号样地表聚性不明显,重度污染区的6、7号样地出现了逆分布现象。在群落多样性指数方面,夏季除了均匀性指数外各项指数的波动比较大。在功能团方面,临汾市郊腐食性动物比例最高,尤其是在重金属污染区,腐食性动物占到了很大比例。而在绿色植物比较茂密的2号样地,植食性动物在数量上占优势。     

淮南煤矿废弃地重金属污染对土壤动物群落的影响

土壤动物是煤矿废弃地生态环境变化最敏感的指示指标,已成为土壤生态恢复研究的热点。通过对淮南大通废弃地土壤重金属含量分析和污染等级确定,选取2条不同污染带的8个采样点调查,分析重金属污染对土壤动物的影响,结果显示:(1)大通煤矿废弃地8个样地,共获得土壤动物2286个,隶属于4门8纲24个类群,优势类群为弹尾目、线虫类和蜱螨目,膜翅目、蜘蛛目等9类为常见类群,其余12类为稀有类群。(2)重金属污染对煤矿废弃地的土壤动物群落影响显著。煤矸石和原化工厂的重金属污染对土壤动物群落的影响表现为:随着污染程度增加,个体数和类群数均呈减小趋势,群落的均匀性、多样性和密度-类群指数也呈降低趋势,优势度指数在煤矸石堆污染带呈逐渐降低趋势,在化工厂污染带则先减小后增加。(3)重金属污染使土壤动物群落多样性降低,群落结构趋于简单,重金属污染与群落结构指数之间呈显著负相关,与土壤有机质等营养物质关系不明显。(4)随污染程度增加,土壤动物垂直分布的表聚性降低。     

长期施肥对麦田大型土壤动物群落结构的影响

于2007、2008年春季在中国科学院封丘农业生态实验站,研究长期定位施肥对麦田大型土壤动物群落结构的影响。调查共获得大型土壤动物3068头,隶属8纲,19目,28科。不同施肥处理条件下土壤动物类群数差异显著(F=2.51, P＜0.05, df=55),个体数差异极显著(F=8.99, P＜0.01, df=55)。结果显示,大型土壤动物的类群数和个体数在有机肥和营养均衡条件下较高,缺磷条件下较低。土壤动物多样性指数(H')以有机肥和营养均衡条件下显著高于营养不均衡和不施肥处理(P＜0.05)。主成分分析结果显示,第一主成分贡献值47.14%,第二主成分贡献值30.10%。经线性检验第一主成分与土壤动物个体数(y=0.335x-2.163,R²=0.51)和类群数(y=0.042x-1.25,R²=0.67)均呈线性关系。总之,长期施用有机肥和营养均衡大型土壤动物群落构成相似。土壤有机质和磷含量是影响土壤动物群落构主要生态因子。     

常绿阔叶林不同砍伐处理下土壤动物的群落特征

为了解不同砍伐处理对常绿阔叶林中土壤动物群落结构的影响, 于2007年7月至2008年4月在浙江天童地区常绿阔叶林中对5个砍伐4年后的恢复样地进行四季采样。样地处理分别是: (I) 去除大树保留萌枝、(II) 去除地表植物保留枯枝落叶层、(III) 去除地表植物和10 cm表土、(IV) 清除下木层保留大树及(V)对照。结果显示: I号样地土壤动物个体数量最多, 除I号样地与III号样地差异显著外(P<0.05), 其他样地间不存在显著差异; 各样地表层土壤动物数量均与5–10 cm、10–15 cm层有显著差异(P<0.05); II号样地类群丰富度最高; I号样地DG指数最高, III号样地最低; 弹尾目、啮目、伪蝎目和半翅目与群落总体特征(DG指数)的相关性都达到了极显著水平(P<0.001)。结果表明砍伐在一定程度上改变了土壤动物的类群组成, 砍伐强度越大, 土壤动物受影响越大。     

DG指数在定量多样性时的缺陷及其内涵解析

生物多样性通常使用物种丰富度、Simpson指数、Shannon-Wiener多样性指数等来进行度量, 但是在土壤动物群落研究中, 由于使用了粗水平的分类方法, 因此即使生境变化很大, 这些多样性指数在评估群落多样性变化时仍然是不适当的。为了克服这种限制, 廖崇惠(1990, 2009)提出用DG指数来代替这些标准的多样性指数, 并在土壤动物生态学领域得到了广泛应用。然而笔者分析发现DG指数与Pielou均匀度指数呈显著的负相关关系(r = –0.534, P = 0.000), 即, 高的均匀度反而有低的多样性。另外, DG指数与类群数(r = 0.648, P = 0.000)和类群密度(r = 0.487, P = 0.000)呈明显的正相关, 类群数的下降可以通过部分类群密度的上升而获得补偿, 群落的类群丢失后却可以获得一个不变的甚至更高的多样性值。因此, 笔者不支持DG指数用于测度生物多样性, 提议使用各类群实际群势与潜在群势比值的平均值来估计群落潜在多度的实现程度。如果继续使用DG指数作为实际生境条件的一个指标, 那么与以往不同, DG指数测度的是该生境群落多度增长的一种潜力。     

加拿大一枝黄花入侵对土壤动物群落结构的影响

外来植物对入侵地土壤动物群落及理化性质影响的研究不仅有助于评估入侵植物对生态系统的影响,而且对探索外来植物入侵的土壤动物学响应机制尤为重要。为了了解加拿大一枝黄花对入侵地土壤动物的群落结构及理化性质的影响,本文分季节分层次对加拿大一枝黄花不同程度的入侵地进行取样,获得土壤动物9900个,隶属3门11纲14目,弹尾目和蜱螨类均为优势类群。入侵程度不同的样地中土壤动物个体数量和类群组成不同。土壤动物个体数量和类群数量表现为轻度入侵区＞中度入侵区＞重度入侵区;多样性指数和均匀性指数表现为轻度入侵区＜中度入侵区＜重度入侵区,优势度指数表现与前两指数相反。加拿大一枝黄花的入侵没有改变土壤动物表聚性特点。非度量多维标度排序分析表明,不同入侵程度下的土壤动物分为3类,即轻度入侵类、中度入侵类、重度入侵类。不同入侵区域土壤的pH、有机质含量、铵态氮、速效钾和速效磷差异显著(P＜0.05),土壤的含水量和温度差异不显著(P＞0.05)。灰色关联分析表明,入侵区域土壤铵态氮对土壤动物关联最大,有机质含量次之,再次是速效磷和pH,土壤含水量的影响最小。因而,加拿大一枝黄花的入侵,改变了入侵地土壤理化性质(尤其是对铵态氮的调控),进而改变了土壤动物的群落结构,创造了利于自身生长、竞争有利的土壤环境。     

三种温带森林大型土壤动物群落结构的时空动态

对帽儿山3种典型森林群落大型土壤动物进行了连续6个月的野外调查研究。通过系统分析,共获得大型土壤动物3604只,隶属于3门6纲17目50科。其中正蚓科(Lumbricidae)、线蚓科(Enchytraeidae)和石蜈蚣目(Lithobiomorpha)为优势类群,常见类群11类。结果表明:(1)水平分布上,密度和生物量红松人工林最高,其次为硬阔叶林,蒙古栎林最少;类群数硬阔叶林最多,蒙古栎林最少;香农指数和丰富度指数均为蒙古栎林最高,红松人工林最低;优势度指数与两者相反;均匀度指数蒙古栎林最高,硬阔叶林最低;(2)垂直分布上,个体密度、类群数及生物量均差异显著(P < 0.001)。3个样地大型土壤动物个体密度表聚性明显;类群数红松人工林自凋落物层向下减少,硬阔叶林和蒙古栎林0-10 cm最多;生物量在0-10 cm土层最大;香农指数随深度增加而减小,优势度指数则相反;(3)在时间变化上,5月和10月个体密度和类群数较多,9月生物量最大;香农指数和优势度指数差异显著(P < 0.01),其他指数各月间无明显差异;(4)与土壤环境因子关系上,总有机碳含量与类群数、个体密度及生物量显著正相关,容重与香农指数显著负相关;典型对应分析结果表明,不同类群大型土壤动物与环境相关性不同。     

指数的性质与应用

密度—类群指数(DG指数)是为研究复杂的土壤动物群落多样性而创建的, 其理论基础是土壤动物群落中各类群互不干扰和互利的关系大于互相竞争的关系, 因而公式中各类群是互相独立、互不影响的。DG指数自1990年建立以来, 经作者及同行学者在不同地带、不同生态系统和不同级别的土壤动物群落研究中运用, 都获得良好的效果, 能真实地反映群落的多样性状况, 显示出它具有广泛的适用性。用情景分析法(scenario analysis)探讨DG指数与Shannon-Wiener多样性指数(H’)的预期效果, 结果显示, 当群落间种数差和均匀度(J)差为正负相反的数值时, Shannon-Wiener指数与DG指数不一致。文中还对土壤动物群落多样性的概念、性质及指数适用性进行了讨论, 认为土壤动物群落在客观上不存在均匀的数量分布, 把“均匀度”看作是多样性的重要指标是不适宜的。DG指数虽然没有直接包含许多信息, 但能在广泛的情况下经得起检验, 因而具有重要的应用价值。     

重金属污染区农田土壤动物群落结构及富集研究——以山西省临汾钢铁厂周围农田为例

本文对重金属污染区山西省临汾钢铁有限公司(临钢)周围农田土壤动物的群落结构特征及其对重金属污染的富集进行了研究。采用手拣法和干漏斗法对临钢周围农田28个样点的土壤动物进行了调查,共获取土壤动物样品数2348,隶属于4门11纲。其中优势类群仅有前气门亚目,常见类群16类,12类稀有类群。对临钢周围农田土壤进行理化性质检测,结果显示土壤呈微碱性,肥力中等,重金属综合污染指数较大。综合土壤动物多样性及周围土壤环境的重金属污染数据,通过统计分析表明:(1)重金属污染地区土壤动物与土壤理化性质的相关性不显著(P>0.05);(2)土壤动物的种类和数量随污染指数的增加而减少;在垂直分布上,表聚性削弱,甚至出现逆分布现象;(3)随着土壤中重金属浓度的增加,蚯蚓和等足目体内的重金属含量也在上升。蚯蚓对Ni元素富集,对6种重金属元素的富集系数依次为Ni>Mn>Cu>Pb=Cr>Zn;等足目对Cu元素富集,对6种重金属元素的富集系数依次为Cu>Mn>Pb>Zn>Ni=Cr。     

青藏东缘若尔盖高寒草甸中小型土壤动物群落特征及季节变化

中小型土壤动物是生态系统的重要组成部分。为了查明高寒草甸生态系统的中小型土壤动物群落特征及其变化动态,2008至2009年间,利用定位观测方法对青藏东缘若尔盖高寒草甸的中小型土壤动物进行了5次调查。结果为:(1)捕获中小型土壤动物9318只,隶属于3门7纲88类;平均密度为39941.67 个/m²;大类群中,线虫纲(Nematoda)的个体数占总个体数的91.50%,蛛形纲(Arachnida)(主要为蜱螨目)、弹尾纲(Collembola)、寡毛纲(Oligochaeta)和昆虫纲(Insecta)分别占3.73%、2.55%、1.12%和1.07%;(2)土壤动物的群落密度、类群数、密度-类群指数、Shannon指数、Simpson指数和Pielou指数均有显著的季节差异(P<0.01或P<0.05),表明高寒草甸生态系统的中小型土壤动物群落多样性对季节变化具有高度敏感性;(3)线虫纲、蛛形纲、弹尾纲、寡毛纲和昆虫纲的密度变化趋势基本一致,并均有显著的季节差异(P<0.05);(4)各季节间的Sorensen群落相似性系数低于Morisita-Horn相似性系数,表明季节变化对群落物种组成的影响相对较强,对优势类群个体密度的影响相对较弱;(5)中小型土壤动物群落的类群数和密度,以及弹尾纲、寡毛纲和昆虫纲的密度均与温度有显著的负相关(P<0.01或P<0.05),线虫和蛛形纲的密度与温度和降水均有不显著的负相关(P>0.05)。研究结果表明若尔盖高寒草甸的中小型土壤动物群落组成和多样性具有明显的季节特征,而温度是影响其季节变化的最主要气候因素;另外,从温度、降水及其年间变化对中小型土壤动物的影响可知全球气候变暖在短期内将会对高寒草甸土壤动物群落产生不利的影响。     

Microtubule dissassembly in vivo: intercalary destabilization and breakdown of microtubules in the heliozoan Actinocoryne contractilis

In the marine heliozoan Actinocoryne contractilis, uninterrupted rods of microtubules stiffen the axopodia and the stalk. Stimulation in sea water elicits an extremely fast contraction (millisecond range) accompanied by almost complete Mt dissociation. Using high-speed cinematography and light transmittance measurements, we have studied the process of Mt disassembly in real time. In sea water, Mt disassembly follows an exponential decrease (mean half time of 4 ms) or proceeds by short steps. Cell contraction and Mt disassembly have been inhibited or slowed down through the use of artificial media. Although kinetics are slower (mean half time of 3 s), the curves of the length change against time look similar. The rapid as well as the slower process are accompanied by the formation of breakpoints on the stalk, from which disassembly proceeds. In specimens fixed during the slowed contraction, the presence across the Mt rods, of a single or multiple destabilization band that may consist of granular material and polymorphic forms of tubulin supports the hypothesis of "intercalary destabilization and breakdown" of axonemal Mts.     

Intermediates in assembly by photoactivation after thermally accelerated disassembly of the manganese complex of photosynthetic water oxidation

The Mn4Ca complex bound to photosystem II (PSII) is the active site of photosynthetic water oxidation. Its assembly involves binding and light-driven oxidation of manganese, a process denoted as photoactivation. The disassembly of the Mn complex is a thermally activated process involving distinct intermediates. Starting from intermediate states of the disassembly, which was initiated by a temperature jump to 47 degrees C, we photoactivated PSII membrane particles and monitored the activity recovery by O2 polarography and delayed chlorophyll fluorescence measurements. Oxidation state and structural features of the formed intermediates of the Mn complex were assayed by X-ray absorption spectroscopy at the Mn K-edge. The photoactivation time courses, which exhibit a lag phase characteristic of intermediate formation only when starting with the apo-PSII, suggest that within approximately 5 min of photoactivation of apo-PSII, a binuclear Mn complex is formed. It is proposed that a MnIII2(di-mu-oxo) complex is a key intermediate both in the disassembly and in the assembly reaction paths.     

A reevaluation of the key factors that influence tomato fruit softening and integrity

The softening of fleshy fruits, such as tomato (Solanum lycopersicum), during ripening is generally reported to result principally from disassembly of the primary cell wall and middle lamella. However, unsuccessful attempts to prolong fruit firmness by suppressing the expression of a range of wall-modifying proteins in transgenic tomato fruits do not support such a simple model. 'Delayed Fruit Deterioration' (DFD) is a previously unreported tomato cultivar that provides a unique opportunity to assess the contribution of wall metabolism to fruit firmness, since DFD fruits exhibit minimal softening but undergo otherwise normal ripening, unlike all known nonsoftening tomato mutants reported to date. Wall disassembly, reduced intercellular adhesion, and the expression of genes associated with wall degradation were similar in DFD fruit and those of the normally softening 'Ailsa Craig'. However, ripening DFD fruit showed minimal transpirational water loss and substantially elevated cellular turgor. This allowed an evaluation of the relative contribution and timing of wall disassembly and water loss to fruit softening, which suggested that both processes have a critical influence. Biochemical and biomechanical analyses identified several unusual features of DFD cuticles and the data indicate that, as with wall metabolism, changes in cuticle composition and architecture are an integral and regulated part of the ripening program. A model is proposed in which the cuticle affects the softening of intact tomato fruit both directly, by providing a physical support, and indirectly, by regulating water status.     

Relation between substrate feeding pattern and development of filamentous bacteria in activated sludge processes: Part III. applications with industrial waste waters

Summary Laboratory scale activated sludge systems were operated under regimes of continuous or intermittent feeding of the waste water. Industrial waste waters from breweries, a dairy plant and a petro-chemical plant were investigated. The systems were started up with sludge from a municipal waste water plant or more often with sludges obtained from the corresponding industrial waste water treatment plants. It was found that intermittently fed systems produced sludges with better settleability characteristics than systems that were continuously supplemented with waste water. Our previous hypothesis that in intermittent systems floc forming bacteria become dominant as a result of higher substrate uptake rates was confirmed and may thus be extended to waste waters containing readily available substrates such as carbohydrates (brewery-and dairy waste water) or acids (petro-chemical waste water). Supplementation of brewery waste water with urea had a negative influence on sludge settleability, especially in continuously operated systems.     

The use of low-quality water on the transport and transformation of waste water in irrigation soils

Waste water use for agricultural production in the semi-arid and arid climate areas is increasingly regarded as a solution for water shortage. Still today many questions remain unanswered about the mid- and long-term effect of irrigation by waste water on plant, soil and human health. In this paper the effect of the use of waste water on the soil hydraulic properties, the solute transport and transformation behaviour is being studied conducting steady state and non-steady state waste water application treatments on undisturbed soil columns and a field plot. Detailed spatial and temporal information on the propagation of water and solute is obtained using tensiometers, soil solute extraction and time domain reflectometry probes. The experimental data are processed using the HYDRUS-2D modeling tool. After calibration, the model is used in a predictive way as to simulate the mid- and long-term effects of the use of treated waste water as irrigation water.     

三种高盐苯胺废水对细菌群落结构的影响

采用PCR-DGGE技术分析了含有不同CODCr、盐、总磷、氨态氮、氯离子、苯胺浓度的3种高盐苯胺废水(1#、2#、3#)驯化的细菌群落结构变化,从分子水平阐明高盐苯胺废水对细菌群落结构的影响.结果表明,不同浓度高盐苯胺废水驯化过程中,2#废水随着浓度的升高,细菌群落多样性逐渐下降;1#废水驯化的细菌群落多样性指数以5%的废水最高,20%与40%的废水最低;3#废水驯化的细菌群落多样性指数以0%和5%的废水最高,20%的废水最低.不同废水对细菌群落多样性有不同的影响,表明适应和突变是驯化过程中细菌适应环境的一个重要作用力.3种不同高盐苯胺废水驯化的细菌群落多样性指数与CODCr、盐含量之间均存在显著负相关,但与氯离子和苯胺含量之间相关不显著.3种废水驯化的细菌的遗传多样性有较大差异,多态位点百分率、Shannon's信息指数和Nei's指数均以3#废水最高,1#废水次之,2#废水最低.但遗传多样性指标与CODCr、盐含量、氯离子和苯胺含量之间均相关不显著.可知细菌群落多样性的变化是由于废水中所含的污染物质的综合作用结果,而非单一的因素.3种废水的5种不同浓度驯化细菌之间的平均遗传距离分别为0.4724、0.4350和0.4902,其中3#废水驯化的细菌遗传变异最大.聚类分析表明,5种不同浓度高盐苯胺废水驯化细菌均可明显地分为两组.1#和2#废水均为0%、5%和10%废水驯化细菌聚成一组,而20%和40%废水驯化细菌聚成另一组; 3#废水为0%与5%废水驯化细菌聚成一组,而10%、20%和40%废水驯化细菌聚成另一组.不同的废水由于水质背景值不同,选择压力不同,导致细菌突变的阈值不同,使得诱导细菌变异程度不同,从而最终引起细菌群落结构的不同.驯化过程中微生物种群的变化使得整个微生物群落能够快速适应外部环境变化.     

高浓度氯化铵工业废水对农作物的污染与毒理试验

为探讨含高浓度氯化铵工业废水对环境与家作物的影响,采用毒理试验方法进行较系统的研究．结果表明,含高浓度氯化铵的工业废水使附近的地面水及土壤受到不同程度的污染,虽然氯化铵是农田肥料的一种,但浓度较高时仍对农作物有致死、致伤及抑制生长的危害,因此,含有高浓度氯化铵的工业废水的处理和对环境造成的影响应予以重视．     

Microtubule-induced focal adhesion disassembly is mediated by dynamin and focal adhesion kinase

Imaging studies implicate microtubule targeting of focal adhesions in focal adhesion disassembly, although the molecular mechanism is unknown. Here, we develop a model system of focal adhesion disassembly based on the finding that microtubule regrowth after nocodazole washout induces disassembly of focal adhesions, and that this disassembly occurs independently of Rho and Rac, but depends on focal adhesion kinase (FAK) and dynamin. During disassembly, dynamin interacts with FAK and colocalizes with focal adhesions. Inhibition of dynamin prevents migration of cells with a focal adhesion phenotype. Our results show that focal adhesion disassembly involves microtubules, dynamin and FAK, and is not simply the reversal of focal adhesion formation.     

Economic Consequences of Increasing Polymer Content for the U.S. Automobile Recycling Infrastructure

Environmental awareness regarding resource use and emissions over the life cycle of the automobile has heightened the concerns for end-of-life (EOL) vehicle disposal. With increasing use of lighter materials to enhance fuel economythe steel dominated content of automobiles is changing to include a greater fraction of polymers. In light of impending regulations for vehicle disposal, various alternatives for remanufacturing and reuse of components and material disposal are under investigation. For example, if shredder operations are used to reclaim metallic materials, then the extent of disassembly will significantly affect proftability as well as the environment.
Using goal programming, we explore changes to the current US. vehicle recycling infrastructure for their effects on dismantler and shredder proftabilities. To investigate the effect of lightweighting on the profrtabilrty of the recycling infrastructure, two specific vehicle designs are compared: a steel unibody and a polymer-intensive vehicle. Other scenarios examine the outcomes for mandating removal of polymer materials during disassembly and for increasing the disposal cost of scrap polymer to that of hazardous waste. The results indicate that, if properly controlled, the current automobile recycling infrastructure in the United States can remain economically viable while it improves with respect to environmental considerations. Alternatively, implementation of certain policies that reduce profitability could cause disastrous consequences, resulting in the economic collapse of the infrastructure.     

造纸废水对离体鱼头呼吸运动的影响

本文采用离体鱼头灌注法,以两个造纸厂的制浆造纸废水对147个鲤鱼头进行了人工灌流。结果表明:废水在低浓度(如4%以下)体积稀释液时,鱼头呼吸速率基本未产生影响,而以较高浓度的废水(如5%以上)稀释液灌流与不含废水的鸭绿江水源地水灌流的对照组鱼头比较,几乎均发生了显著性变化,即对鱼鳃盖运动产生了抑制作用,出现了Biot氏呼吸。以往学者们认为,造纸废水主要是由于水中溶解氧(DO)减少而使鱼类致死的,但本工作灌注液中已人工给予足够的DO,提示:有毒物质本身似已直接危及延髓呼吸中枢。 实验同时表明,离体鱼头灌注法可供环境保护部门应用于含多种有机毒性物质的制浆造纸废水的现场监测。