豫南罗索线虫防制白纹伊蚊现场试验

现场试验已证实豫南罗索线虫(Romanomermisyunanensis)对三带喙库蚊、致倦库蚊有较好的防制效果,对伊蚊属等蚊虫亦很敏感。作者于1987年7、8月份针对白纹伊蚊在自然条件下的孳生特性,用该线虫寄生前期幼虫进行了初步现场防制试验,结果如下。材料和方法一、豫南罗索线虫寄生前期幼虫为本室培养,经稀释计数后备用,从寄生前期幼虫孵出至释放于现场水体,不超出16小时。二、现场试验于1987年7—8月在成都市郊进行,从露天有积水的陶盆、陶罐内取出部分幼虫解剖及鉴定虫种,证实为白纹伊蚊且无索线虫寄生。试验时记录容器大小、积水量、容器底部沉…     

拟草果总黄酮制备纯化及抗炎活性研究

该文在前期研究的基础上,以拟草果的甲醇粗提液为原料,研究拟草果总黄酮成分的纯化方法以及考察拟草果总黄酮的抗炎活性。结果表明:通过静态吸附-洗脱试验,筛选出HP-20为纯化拟草果总黄酮的最佳大孔吸附树脂;以吸附率、解吸率等参数为指标,考察上样液和洗脱液的质量浓度、体积、流速等因素对纯化工艺的影响,确定最佳工艺条件为上样液质量浓度0.5 mg·m L^-1、上样体积流量4 m L·min^-1、上样体积15 BV、洗脱剂乙醇浓度70%、洗脱流速2 m L·min^-1、洗脱剂用量10 BV,在此条件下纯化的总黄酮保留率为65.48%;通过检测获得的拟草果总黄酮对脂多糖刺激的小胶质BV2细胞中白介素(IL)-6水平的影响,发现其可显著下调炎症因子IL-6的表达,具有一定的抗炎活性。     

黄粉虫营养成分的分析研究

为解决饲养广西特产经济动物蛤蚧的饲料难题,我们从北京动物园引进黄粉虫TenebriomolitorL．繁殖饲养蛤蚧获得成功。经多年试验证明,用黄粉虫喂养蛤蚧生长快,个体肥,特别秋末春初更为突出,一般每条蛤蚧月增重1．7～18．8g,比用灯光诱虫或用蝗虫、蝇蛆喂养的效果好[1]。目前许多单位利用黄粉虫喂养蝎子、蛤蚧、龟、鸟、蜈蚣、牛娃等经济动物效果很好,为了进一步开发利用这一优良昆虫饲料,对它的营养成分进行测定分析,测定结果如下。1材料与方法采用继代繁殖后的成熟幼虫、蛹、成虫进行测定分析。饲养堂为4×6m2的平房。一般温度在1…     

活体微藻吸附水体中Cd2+的性能特征

【目的】藻类对重金属吸附和吸收是重金属进入食物链的重要渠道之一。研究活体微藻对水体中Cd~(2+)的吸附性能和吸附机理,旨在为Cd~(2+)等重金属离子进入水体后的去向及去除提供理论依据。【方法】选取地表水普遍存在的4种微藻:钝顶螺旋藻(Spirulina platensis)、铜绿微囊藻(Microcystis aeruginosa)、四尾栅藻(Scenedesmus quadricauda)和小球衣藻(Chlamydomonas microsphaera)作为试验材料,通过室内模拟实验,利用Langmuir、Freundlich和Dubinin-Radushkevich(D-R)3种等温吸附模型,研究4种活体微藻对Cd~(2+)的吸附规律及吸附参数。【结果】4种微藻对水体Cd~(2+)吸附均可以用Langmuir、Freundlich和D-R模型描述,其中用Langmuir模型拟合钝顶螺旋藻、Freundlich模型拟合小球衣藻、D-R模型拟合铜绿微囊藻和四尾栅藻的吸附效果最佳。四尾栅藻对Cd~(2+)的吸附量最高,而钝顶螺旋藻对Cd~(2+)的吸附量最低,但与Cd~(2+)的亲和力最强,4种微藻吸附Cd~(2+)主要是以离子代换为主的化学吸附。【结论】微藻对Cd~(2+)均有较强的吸附能力,会引起以微藻为食的水生动物Cd~(2+)富集;微藻也是去除水体Cd~(2+)的潜在吸附剂原料。     

长期水陆周期性变化条件下香根草形态性状和生物量分配的可塑性

香根草是能够长期适应三峡水库消落带生境的少数物种之一。虽然国内对香根草的引种栽培和研究已有几十年的历史,但是对香根草在三峡库区消落带长期水陆周期性变化条件下的生态适应对策还知之甚少。为此,以2008年在三峡水库巫山段消落带建立的香根草引种栽培试验示范基地为研究平台,在2016年对海拔166—169 m、169—172 m和172—175 m区段的香根草的形态性状、生物量及其分配特征进行了研究。结果表明：(1)海拔166—169 m香根草的分蘖株数、平均株高、节间数量、节间长度、叶片数/分蘖株、叶片数/丛、叶片长等各指标值均低于海拔169—172 m和海拔172—175 m,海拔166—169 m与其它海拔区段的节间数量差异显著(P<0.05);(2)海拔166—169 m香根草的根系数量最少,但根系长度最长;(3)海拔166—169 m无节间的香根草株数最多,且与海拔172—175 m和海拔169—172 m差异显著(P<0.05);(4)不同海拔区段香根草的总生物量大小表现为海拔172—175 m>海拔169—172 m>海拔166—169 m,且海拔166—...     

东方栓孔菌菌丝体生物吸附剂对染料的脱色作用及其吸附机制研究

利用东方栓孔菌Trametes orientalis菌丝体制得的生物吸附剂,对刚果红、结晶紫、铬天青、亚甲基蓝和中性红5种染料进行了脱色试验,对脱色效果较好的染料进行了影响因子优化,并通过红外光谱分析、化学修饰等方法研究其吸附作用的机制。结果显示：东方栓孔菌菌丝体生物吸附剂对结晶紫有相对较好的脱色效果;在优化的影响因子中,0%–3.0%（m/v）浓度范围内,盐度对染料脱色有促进作用;表面活性剂促使脱色率增加,吐温60浓度为1.5%（v/v）时脱色率可达83.84%;温度为43℃、初始pH为3.0、振荡培养10d后吸附率最高达91.54%。红外光谱分析及化学修饰结果表明菌丝体对染料的吸附作用主要是由它们之间的静电作用力所致。     

无机盐、激素与真菌联合诱导土沉香抗逆能力的研究

为了探究无机盐、激素与真菌联合诱导土沉香(Aquilaria sinensis)抗逆性及其与结香前期木芯变色长度之间的相关关系,以10年生土沉香为材料,采用均匀试验设计,开展了3种无机盐、3种激素及3种真菌组合试验。结果表明:(1)土沉香树体POD和SOD活性和MDA含量呈先升高后降低趋势,CAT活性在诱导后1天最高,随后呈下降趋势;(2)无机盐与真菌处理下土沉香的抗逆能力大于激素与真菌处理,其中无机盐与真菌组合试验的处理4(1.0%CaCl2+0.5%FeSO4+2.0%NaCl+黑绿木霉∶腐皮镰孢∶龙眼焦腐(1∶1∶1))和激素与真菌组合试验的处理2(0.01%茉莉酸甲酯+0.1%乙烯利+0.2%水杨酸钠+黑绿木霉∶腐皮镰孢∶龙眼焦腐(1∶1∶1))分别为同类处理最高;(3)土沉香抗逆能力高低与木芯变色长度存在显著正相关性;(4)理论上,土沉香抗逆能力最强诱导组合分别为0.93%CaCl2+0.53%FeSO4+2.5%NaCl+黑绿木霉∶腐皮镰孢∶龙眼焦腐(1∶1∶1)和0.005%茉莉酸甲酯+0.006%乙烯利+0.2%水杨酸钠+黑绿木霉∶腐皮镰孢∶龙眼焦腐(1∶1∶1)。     

不同水分条件对冬小麦根系时空分布、土壤水利用和产量的影响

为了明确华北严重缺水区晚播冬小麦灌水对根系时空分布和土壤水分利用规律的影响,以冬小麦石麦15为材料,利用田间定位试验研究了不同灌水处理(春季不灌水W0;春季灌拔节水75mm,W1;春季灌起身水、孕穗水和灌浆水共225mm,W3)对根系干重密度(DRWD)、根长密度(RLD)、体积密度、分枝数等在0—200cm土层的垂直分布、动态变化及其对耗水和产量的影响,结果表明:随着春季灌水量的减少,开花后0—80cm土层的根干重密度、根长度密度、体积密度和分枝数密度均显著减少,80cm—200m土层的根干重密度、根长度密度、体积密度和分枝数密度却显著增加,并且显著增加冬小麦在灌浆期间对100cm以下深层土层水分的利用,总耗水量W1和W0分别比W3减少70.9mm、115.1mm,土壤耗水量分别比W3增加79.1mm、108.9mm,子粒产量W1和W0分别比W3减少653.3kg/hm2、1470kg/hm2,水分利用效率(WUE)则分别比W3提高0.09kg/m3、0.06kg/m3。晚播冬小麦春季灌1水(拔节水)可以促进根系深扎,增加深土层的根系分布量,提高对深层土壤贮水的吸收利用量,有利于实现节水与高产的统一。     

不同坡度缓冲带径流污染净化效果及其最佳宽度

在前期资料调研、小试试验和基地选址的基础上,选择百慕大草皮构建了2％、3％、4％和5％四种不同坡度结构的滨岸缓冲带试验基地,开展径流污染物净化效果现场试验。结果表明,坡度与缓冲带径流悬浮固体颗粒物（SS）截留效果显著相关,19m长的2％坡度缓冲带末端的SS截留率达到84％,而5％坡度只有70％;2％坡度缓冲带末端渗流出水总氮（TN）、总磷（TP）平均浓度分别比5％坡度低1．63mg&#183;L^-1和0．1mg&#183;L^-1,在进水TP平均浓度范围为0．9—1．0mg&#183;L^-1时,4种不同坡度试验带的渗流出水TP浓度均低于《地表水环境质量标准》（GB3838-2002）Ⅳ类水标准;通过计算,末端SS去除率为80％时,2％坡度需要的缓冲带最佳宽度为16．1m,5％坡度则为24．7m,两者相差达8．6m。     

晋西黄土区土地利用对降雨入渗产流模式和优先流分布的影响试验研究

黄土高原退耕还林(草)工程显著改变了河川径流过程,但其作用机制尚不明晰。选取晋西黄土区4种典型下垫面(20年和30年刺槐人工林地、草地、休耕地)分别开展连续3场模拟降雨试验,观测坡面入渗产流过程,并结合染色示踪和图像处理软件技术,分析土地利用类型对坡面降雨入渗产流模式和优先流分布的影响。结果表明：(1)累积入渗量和优先流发育程度均表现为刺槐林地>草地>休耕地,刺槐林地优先流对总入渗的贡献是草地和休耕地的2.5—4.5倍,但优先流贡献均不超过10%,仍以基质流入渗为主。(2)4种用地类型降雨入渗主要补给地表60—70cm土层,前期降雨均匀增加表层土壤含水率,而后期降雨补给深层土壤水分的空间变异性显著增强。(3)刺槐林地产流量及径流系数均显著小于草地和休耕地,且前期含水量对20年刺槐林地的影响较小,而显著影响草地和休耕地径流系数。(4)直径d<1mm的细根显著促进降雨入渗和优先流发育,而d>5mm的粗根与入渗量和基质流量呈显著负相关。较高的土壤初始含水率、容重和粘粒含量会抑制入渗和优先流的发生。研究说明不同土地利用类型将改变降雨入渗产流过程及土壤水运动形式。     

Attachment strength of an adhesive nuisance mussel,limnoperna fortunei,against water flow

The attachment strength of the freshwater mussel Limnoperna fortunei against water flow was studied. Newton's expression successfully described the hydrodynamic drag force acting on the mussel with a drag coefficient value of 1.03. The drag‐resistant force (defined as hydrodynamic drag force at mussel detachment) was smaller than the detachment force measured using a tensile load test. A fairly good correlation was obtained between the drag‐resistant force and the number of secreted threads. The drag‐resistant force divided by the number of threads increased with shell size, suggesting that byssal thread strength increased with mussel growth. For the mussel specimens obtained from a water transmission pipe, thread width increased with shell size. However, thread width was not dependent on current velocity. There was no correlation between the number of secreted threads and shell length, which indicated that the number of secreted threads did not change with mussel size. Therefore, the water velocity needed to detach mussels increases with shell size of the mussel when the number of secreted threads is constant. The increases in the water velocity to detach mussels with larger shells suggests that the mussel becomes more resistant to water flow as it grows. It is estimated that a flow velocity of around lms^‐1 is critical for attachment/detachment of a juvenile mussel with a shell length of a few millimeters and one hundred byssal threads.     

Downstream dispersal of zebra mussels (<Emphasis Type="Italic">Dreissena polymorpha</Emphasis>) under different flow conditions in a coupled lake-stream ecosystem

Dispersal, establishment, and spread of aquatic invasive species such as the zebra mussel (Dreissena polymorpha) can be influenced by riverine velocities and volumetric flows in invaded lake-stream ecosystems. Zebra mussels, which have a planktonic larval form (veliger), disperse rapidly downstream from a source population. Concentrations, dispersal, and body conditions of zebra mussel veligers were studied under different volumetric flow, or discharge, conditions in a coupled lake-stream ecosystem in northern Texas, USA. Veliger densities in lotic environments were strongly related to population dynamics in upstream lentic source populations. A strong exponential decrease in veliger density was observed through a 28-km downstream study reach. Increased water releases from the source reservoir increased veliger flux and dispersal potential, concomitantly increasing veliger flux and decreasing transit time. However, passage through release gates in the dam and increased turbulence in the river during high-discharge events could negatively affect body condition of veligers, and veliger body condition generally decreased from the source population to the farthest downstream site and was lower for veligers during periods of high discharge. Thus increased discharge appears to reduce the proportion of viable veligers because of increased turbulence-induced mortality. Colonization of distant downstream reservoirs can occur if discharge and propagule pressure are sufficient or if interim habitats are suitable for establishment of in-stream populations.     

Reciprocal Effects between Burying Behavior of a Larval Dragonfly (Odonata: Macromia illinoiensis) and Zebra Mussel Colonization

Invasive zebra mussels (Dreissena polymorpha) often colonize dragonfly larvae, especially spawling species whose survivorship to emergence as terrestrial predators is consequently reduced. Using individuals of the sprawler, Macromia illinoiensis, as their own controls, we compared the burying behavior of penultimate instar larvae before (i.e. baseline) and after their colonization by zebra mussels under ambient conditions. Individuals that took longer to bury themselves when mussel-free had a higher rate of colonization by mussels over a five-day period compared to those that buried faster. In contrast, the depth at which individuals buried when mussel-free was not predictive of subsequent colonization rate. Although mean bury time did not differ between baseline and when an individual carried one or more mussels, colonized larvae buried more shallowly than when mussel-free. Moreover, attached mussels increased the risk of subsequent colonization by zebra mussels. After naturally losing all of their attached mussels, bury time and depth of individuals did not differ from their baseline behavior, indicating that the changes in the behavior of colonized individuals were due to mussel loads and not their time in captivity. Under natural conditions, the positive feed-back between mussel attachment and increasing vulnerability to colonization helps explain how mussel loads, which are lost at molting, can accumulate quickly over the duration of the final larval stadium. Because zebra mussel attachment decreases the crypsis that that a M. illinoiensis gains from burying, the invasive mussel may also make dragonfly larvae more detectable to visual predators.     

Susceptibility of larval dragonflies to zebra mussel colonization and its effect on larval movement and survivorship

Colonization by the zebra mussel, Dreissena polymorpha, was quantified for five dragonfly species that differed in size and larval habits in a Michigan lake. Both larger size and a non-burrowing habit independently increased susceptibility to colonization. In 2005, over 50% of the final instars of the sprawlers Didymops transversa and Hagenius brevistylus were colonized, as well as younger instars. Rarely colonized were Progomphus obscurus and Dromogomphus spinosus, whose larvae burrow under sand, and the sprawler Epitheca princeps, whose final instars were lightly covered with sand. Hagenius larvae that had been preyed upon carried more mussels than those dying of other causes. More generally, mussel attachment decreased the probability that sprawlers left the water to emerge, the distance that some species traveled before emerging, and the ability of an overturned sprawler to right itself. On average, final instars of Didymops and Hagenius remaining in the water carried three times as many mussels as individuals known to emerge. Compared to uncolonized individuals, Epitheca and Progomphus with mussels emerged closer to the water line. Among colonized Didymops, the distance traveled on land before emerging decreased with increasing mussel load. Of the colonized Didymops that could right themselves, righting time increased with mussel load. Because the two common species of sprawlers were disproportionately colonized, and mussel attachment decreased their chances of emerging, our results suggest that D. polymorpha has the potential to affect the community structure of this guild of aquatic and terrestrial predators. Handling editor: R. Bailey     

Suppression of microzooplankton by zebra mussels: importance of mussel size

1. The zebra mussel (Dreissena polymorpha) is amongst the most recent species to invade the Great Lakes. We explored the suppressive capabilities of mussels 6–22-mm in size on Lake St Clair microzooplankton (< 240)μm) in laboratory experiments. 2. Absolute suppression of rotifers and Dreissena veliger larvae was proportional to mussel shell length for individuals larger than 10 mm; larger zooplankton, mainly copepod nauplii and Cladocera, were not affected. Mussel clearance rates on rotifers generally exceeded those on veligers, although rates for both increased with increasing mussel size. Rotifer-based clearance rates of large (22 mm) mussels approached published values for phytoplankton food. 3. Most zooplankton taxa, particularly rotifers, declined significantly in western Lake Erie during the late 1980s concomitant with the establishment and population growth of zebra mussels in the basin. Densities of some taxa subsequently increased, although rotifers and copepod nauplii densities remained suppressed through 1993. Available evidence indicates that direct suppression by Dreissena coupled with food limitation provides the most parsimonious explanation for these patterns.     

Putative identification of expressed genes associated with attachment of the zebra mussel (Dreissena polymorpha)

Because of its aggressive growth and firm attachment to substrata, the zebra mussel (Dreissena polymorpha) has caused severe economic and ecological problems since its invasion into North America. The nature and details of attachment of this nuisance mollusc remains largely unexplored. Byssus, a special glandular apparatus located at the root of the foot of the mussel produces threads and plates through which firm attachment of the mollusc to underwater objects takes place. In an attempt to better understand the adhesion mechanism of the zebra mussel, the suppression subtractive hybridization (SSH) assay was employed to produce a cDNA library with genes unique to the foot of the mussel. Analysis of the SSH cDNA library revealed the presence of 750 new expressed sequence tags (ESTs) including 304 contigs and 446 singlets. Using BLAST search, 365 zebra mussel ESTs showed homology to other gene sequences with putative functions. The putative functions of the homologues included proteins involved in byssal thread formation in zebra and blue mussels, exocrine gland secretion, host defence, and house keeping. The generated data provide, for the first time, some useful insights into the foot structure of the zebra mussel and its underwater adhesion.     

Larval development of the invasive charru mussel,Mytella strigata (Bivalvia: Mytilidae)

ABSTRACT

The South American charru mussel, Mytella strigata, was recently recorded in Singapore waters, possibly introduced into Southeast Asia through shipping. The mussels have rapidly spread across estuarine coastal mudflats. Adult mussels were collected, spawned in aquaria and larvae were successfully cultured to the juvenile stage in the laboratory. The larval morphology and development of M. strigata is described in this paper. D-shaped veligers were produced within 20 h of fertilization and were approximately 75 µm in shell length. These larvae were capable of settlement two weeks post fertilization. Given an adequate amount of food, they were able to grow up to 1 mm in shell length within 30 days. The larval shell of M. strigata possesses anterodorsal G2 hinge teeth as distinct wavy ledges, with a pitted resilial ridge clearly evident in the juvenile shell.     

Mortality of zebra mussel, Dreissena polymorpha, veligers during downstream transport

1. Streams flowing from lakes which contain zebra mussels, Dreissena polymorpha , provide apparently suitable habitats for mussel colonization and downstream range expansion, yet most such streams contain few adult mussels. We postulated that mussel veligers experience high mortality during dispersal via downstream transport. They tested this hypothesis in Christiana Creek, a lake-outlet stream in south-western Michigan, U.S.A., in which adult mussel density declined exponentially with distance downstream.
2. A staining technique using neutral red was developed and tested to distinguish quickly live and dead veligers. Live and dead veligers were distinguishable after an exposure of fresh samples to 13.3 mg L⁻⁻¹ of neutral red for 3 h.
3. Neutral red was used to determine the proportion of live veligers in samples taken longitudinally along Christiana Creek. The proportion of live veligers (mean ± SE) declined from 90 ± 3% at the lake outlet to 40 ± 8% 18 km downstream.
4. Veligers appear to be highly susceptible to damage by physical forces (e.g. shear), and therefore, mortality in turbulent streams could be an important mechanism limiting zebra mussel dispersal to downstream reaches. Predictions of zebra mussel spread and population growth should consider lake-stream linkages and high mortality in running waters.     

Effect of the western pearlshell mussel Margaritifera falcata on Pacific lamprey Lampetra tridentata and ecosystem processes

Suspension feeders concentrate organic material from the water column and enhance deposition to the surrounding benthos. On the South Fork of the Eel River (Mendocino, California) two suspension feeders, the freshwater mussel Margaritifera falcata and Pacific lamprey larvae Lampetra tridentata, co‐occur in areas with low flow velocities and boundary sheer stresses. We investigated mussel/lamprey larvae interactions, and their impacts on nutrient and organic matter cycling, in flow‐through enclosures placed where lamprey larvae and mussels naturally occurred. Over the 80‐day study, lamprey larvae grew faster in the presence of mussels and in food addition treatments. Our results suggest that lamprey larvae benefit from native mussels, and that lamprey populations and organic matter retention in rivers may decrease with the rapid decline of native freshwater mussels.     

Effects of Artificial Filamentous Substrate on Zebra Mussel (Dreissena polymorpha) Settlement

Though a great deal of research focuses on the range expansion and presence of adult zebra mussels, there is still a need to understand the processes of larval settlement and how that relates to adult populations. There is evidence that marine bivalves preferentially settle on filamentous substrates such as hydroid colonies and algae; however, similar studies are rare in freshwater systems. We examined the importance of filamentous substrate for the settlement of the zebra mussel (Dreissena polymorpha) larvae by deploying PVC settlement plates with and without polypropylene filaments in the Bark River for a 6-week period. Larval supply was monitored weekly. Our results suggest that artificial filaments facilitated recruitment, primarily by increasing surface area available for attachment. Mussels on artificial filaments were significantly smaller in size than mussels attached to filamentous or control plate surfaces, providing some evidence that mussels may detach from filamentous substrate after initial settlement. This study adds to our general understanding about the role of filamentous substrates in the process of larval settlement and suggests that substrates colonized by filamentous epibionts may face increased risk of fouling by zebra mussels. An erratum to this article is available at .