福建海坛岛长江澳沙滩自由生活海洋线虫群落研究

于2013—2014年间在海坛岛长江澳沙滩采样,对小型底栖动物的类群组成、丰度及分布,自由生活海洋线虫(简称海洋线虫)群落的优势属、摄食类型、年龄结构及性比、物种多样性等方面进行研究。结果表明:小型底栖动物年平均丰度为(810.87±696.75)个/10 cm~2。在鉴定出的16个类群中,海洋线虫的丰度占小型底栖动物总丰度的52.36%,其次为腹毛虫,占21.14%。海洋线虫的年平均丰度为(424.54±400.23)个/10 cm~2,季节变化总趋势为夏季((783.45±336.45)个/10 cm~2)春季((600.67±309.42)个/10 cm~2)秋季((298.26±424.57)个/10 cm~2)冬季((113.05±95.79)个/10 cm~2)。4个季度共鉴定出海洋线虫105种或分类实体,隶属于75个属,26个科。4个季度数量百分比超过5%的优势海洋线虫属有10个,分别是Axonolaimus、Theristus、Metachromadora、Mesacanthion、Rhynchonema、Epacanthion、Microlaimus、Viscosia、Lauratonema和Enoploides,不同季度的优势属存在差异。CLUSTER聚类表明,春、夏、秋季各潮带海洋线虫群落较为相似,与冬季差异较大。海洋线虫4种摄食类型年平均丰度百分比由高到低的顺序是1B (32.19%) 2A (31.32%) 2B (31.12%) 1A (5.37%);春夏季以2A和1B为主导,秋冬季以2B和1B为主导。海洋线虫群落的物种多样性最高值出现在秋季(d=8.45,H′=3.36),最低在冬季(d=7.36,H′=2.92),春季与夏季的多样性相当;周年幼体的数量所占比例为45.47%,成体中雌雄个体比例为1.10∶1。     

不同采样时期渤海自由生活海洋线虫种类组成的比较

在渤海的3个典型站位B1、E5和E1,以3个不同采样时期的沉积物样品（1997年6月、1998年9-10月份和1999年4-5月份）,研究了渤海自由生活海洋线虫的种类组成变化。结果表明：自由生活海洋线虫的摄食类型比例在同一个站位3次不同采样均有变化,其中B1站和E5站3个采样时期表现为3种不同的摄食类型分布;将线虫分为3个时期所进行的年龄结构和雌雄比研究表明,在线虫群落中幼龄个体一般占到线虫群落总数的一半以上;对3个站位线虫群落的多样性研究表明,离黄河口最近的B1站,出现种类数量最少,位于渤海中部的E5站,出现种类数量较多;3个不同采样时期的比较,以1997年6月份群落中出现的种类数最多,1999年4-5月份出现的最少。对其群落结构的分析表明,同一个站位不同采样时期,优势种的类型基本相同,变化主要表现在优势种丰度大小的差异,其群落组成结构相对稳定。     

厦门岛附近自由生活海洋线虫的研究——微口线虫属（Genus：Terschellingia De Man,1888）的两种

本文报道了厦门岛附近潮间带泥基质滩所分离到的2种自由生活线虫。其中长尾微口线虫（Terschellingia longicaudata de Man,1907）在头部感觉毛以及交合刺的形态及结构等方面很的符合前人的描述,但肛前附器的个数有差别;另外一种由于其分类地位尚不能确定,本文中建议给出其尾的分类,其主要特征为短的尾部和很发达的交合刺。     

厦门岛海滩海洋线虫数量及其种类分布的初步研究

选取了 5个月份对厦门岛海滩的海洋线虫数量和种类分布进行了研究。该海滩为沙、泥质滩 ,其低潮区的表面覆盖一层较厚的泥质。结果显示 ,5个月份中线虫密度最大可以达到 ( 2 6 7± 0 39)× 1 0 6个 m2 ,最小 ( 1 6 1± 0 1 7)× 1 0 6个 m2 ,且 5个月份的线虫平均密度之间没有很显著的差异 (P >0 0 1 )。线虫的数量呈现明显的垂直分层 ,即种群数量的大部分集中于上层 ,并且这种分布没有明显的季节变化特点。 5个月份中线虫的优势种类相对较为固定 ,而垂直分层的较深层中线虫种类有较明显的变化。在比较其它海区类似沙滩资料的基础上 ,对本文的结果进行了讨论。     

石油分散剂BP-1100X对海洋围隔生态系的影响研究

在分散剂作用下,围隔水体中浮游动物种群数量明显减少,浮游植物因捕食压力不大而诱发“赤潮”.分散的原油在围隔水体中的生态效应变得不明显,细菌生物量和生产力在实验前期比对照组高,后期则随原油降解而波动,这表明微生物积极参与了原油的降解活动。实验揭示,由于添加物的毒性作用促成的生态系的不平衡,也可最终导致“赤潮”发生。     

土壤线虫群落对大连石门山森林植被恢复的响应

2007年9月至2008年8月对大连石门山不同植被恢复方式的样地进行土壤线虫调查,淘洗-过筛-浅盘法提取土壤线虫,应用类群属数、个体密度、多样性指数和功能类群指数等多个群落参数,研究不同植被恢复方式间土壤线虫群落特征的差异。共捕获线虫8577条,分别隶属于线虫动物门2纲7目26科43属,个体密度平均4.77条/g干土。研究结果表明,土壤线虫数量存在明显的季节波动,秋季明显高于夏季和春季;土壤线虫群落多样性指数、均匀度指数、丰富度指数和营养类群指数大小依次为阔叶林、针叶林和混交林,而优势度指数却表现为:针叶林混交林阔叶林;土壤线虫群落营养类群f/b值、MI指数、PPI指数、MMI指数、MI2-5指数、SI指数和EI指数均表现为:阔叶林针叶林混交林,而PPI/MI指数则表现为:混交林针叶林阔叶林,表明混交林受干扰明显;土壤理化特征与线虫数量、属数、生态指数间也存在明显相关关系。因此,植被恢复过程中土壤线虫群落结构分异及动态是一个重要的生态响应过程,能为进一步研究土壤生物在植被演替中的地位和作用以及土壤生物多样性保护提供基础数据。     

土壤线虫群落对闽北森林植被恢复的响应

为了考察地上植物群落的演替与土壤线虫群落的相互关系, 作者对闽北退化常绿阔叶林不同恢复阶段的土壤线虫群落进行了为期一年的定位研究。研究表明, 线虫群落对植被不同恢复阶段有不同的响应, 各恢复阶段线虫数量差异显著(P<0.01), 从大到小依次为: 荒地(Wj)、天然阔叶林(Cc)、针阔混交林(Clc )、针叶林(Pm); 土壤线虫数量的季节波动明显, 属数与个体密度均体现为春季＞冬季＞秋季＞夏季, 而夏季极显著少于其他季节(P<0.01); 土壤线虫群落DG指数与丰富度指数从大到小依次为天然阔叶林、荒地、针阔混交林和针叶林。而多样性顺序却表现为: 荒地>天然阔叶林>针阔混交林>针叶林; 不同恢复阶段土壤根系生物量、土壤理化特征存在明显的空间变异, 并且线虫数量与根系生物量、土壤含水率、土壤孔隙度、土壤有机质、全氮以及速效磷具有显著正相关关系。因此, 植被恢复过程中土壤线虫群落结构分异及其动态是一个重要的生态响应过程, 能为进一步研究土壤生物在植被演替中的地位和作用以及土壤生物多样性保护提供基础数据。     

Laboratory experiments on the infaunal activity of intertidal nematodes

The impact of oxygen on the vertical distribution of an intertidal nematode community was investigated in a manipulation experiment with sediments collected from the Oosterschelde (The Netherlands). The vertical distribution of nematodes was examined in response to sediment inversion in perspex cores with or without the presence of an air-flushed silicone tube introducing oxygen to the bottom sediment layer. Following an incubation of 1 week, peak densities of nematodes were recorded in the deep layers of the sediment in cores with subsurface oxygenation. In contrast, this concentration of nematodes was absent in the cores that lacked bottom oxygenation and the majority of the total assemblage was still located in anoxic sediment layers. This suggests that oxidised sediments with traces of oxygen represent favourable conditions for nematodes and indicates that these nematodes are tolerant to short-term anoxia and burial. Observations on the species level suggest that oxygenation, primarily through its direct impact on geochemical properties of the sediment, may be an important factor governing the subsurface activity of nematodes.     

Large‐scale distribution patterns of mangrove nematodes: A global meta‐analysis

Mangroves harbor diverse invertebrate communities, suggesting that macroecological distribution patterns of habitat‐forming foundation species drive the associated faunal distribution. Whether these are driven by mangrove biogeography is still ambiguous. For small‐bodied taxa, local factors and landscape metrics might be as important as macroecology. We performed a meta‐analysis to address the following questions: (1) can richness of mangrove trees explain macroecological patterns of nematode richness? and (2) do local landscape attributes have equal or higher importance than biogeography in structuring nematode richness? Mangrove areas of Caribbean‐Southwest Atlantic, Western Indian, Central Indo‐Pacific, and Southwest Pacific biogeographic regions. We used random‐effects meta‐analyses based on natural logarithm of the response ratio (lnRR) to assess the importance of macroecology (i.e., biogeographic regions, latitude, longitude), local factors (i.e., aboveground mangrove biomass and tree richness), and landscape metrics (forest area and shape) in structuring nematode richness from 34 mangroves sites around the world. Latitude, mangrove forest area, and forest shape index explained 19% of the heterogeneity across studies. Richness was higher at low latitudes, closer to the equator. At local scales, richness increased slightly with landscape complexity and decreased with forest shape index. Our results contrast with biogeographic diversity patterns of mangrove‐associated taxa. Global‐scale nematode diversity may have evolved independently of mangrove tree richness, and diversity of small‐bodied metazoans is probably more closely driven by latitude and associated climates, rather than local, landscape, or global biogeographic patterns.     

悉生培养微缩体系食细菌线虫提高土壤激素含量的机制

研究土壤食细菌线虫与细菌的相互作用及其生态功能是土壤生态学的核心内容之一。食细菌线虫取食细菌可以促进土壤中氮素的矿化,提高氮素养分的供给,改善土壤的营养条件,从而促进植物的生长发育。土壤食细菌线虫促进植物根系生长的"养分作用机制"已得到确认,而"激素作用机制"还存在争议。从供试土壤中筛选获得一株高效产IAA细菌和两种不同cp值的食细菌线虫,通过设置简化的悉生培养系统,对这两种土著食细菌线虫与土著产IAA细菌之间的相互作用,及其对土壤中IAA含量变化的影响进行研究。结果表明:两种食细菌线虫的取食均能促进细菌数量和活性的增强,食细菌线虫与产IAA细菌相互作用也能显著增加土壤中IAA的含量;这些促进作用受到接种食细菌线虫的种类以及培养时间的影响:在培养第10天和第20天时,接种cp值为1的中杆属食细菌线虫显著增加了产IAA细菌的数量;在培养第10天和第30天时,相比较接种cp值为2的头叶属食细菌线虫,接种中杆属食细菌线虫显著提高了土壤中IAA的含量。     

人工微宇宙下粘细菌捕食对微生物群落结构的影响

【目的】人工微宇宙条件下测试粘细菌捕食对微生物群落结构的影响,模拟粘细菌捕食对微生态系统的调控作用。【方法】采用Lawn predation法,测定粘细菌EGB对9种猎物菌的捕食直径,以确定其对猎物菌的捕食能力。通过高通量测序技术分析粘细菌捕食引起的微生物群落结构变化。【结果】粘细菌EGB对9种不同猎物菌的捕食能力差异显著,粘细菌对热带芽孢杆菌的捕食能力显著高于其他细菌(P<0.05)。在含有9种猎物细菌的人工微宇宙系统中添加不等量粘细菌,均可显著降低细菌群落的多样性指数(Shannon)。PCoA结果表明粘细菌捕食可影响微宇宙微生物群落结构。人工微宇宙培养24 h后,7种猎物菌相对丰度显著降低(LefSe,P<0.05),但洋葱伯克霍尔德菌的相对丰度显著升高(P<0.05)。人工微宇宙实验的结果表明,粘细菌添加是造成其微生物群落结构改变的主要影响因素,且添加最小剂量的粘细菌(1 mL)也有显著的影响效果;随着培养时间的增加,洋葱伯克霍尔德菌是唯一能抵抗粘细菌捕食并具有较高丰度的猎物细菌。【结论】粘细菌捕食能够调控微宇宙中微生物的群落结构,为其对土壤生态的调控研究奠定了理论基础。     

Field and microcosm experiments to evaluate the effects of agricultural Cu treatment on the density and genetic structure of microbial communities in two different soils

The effects of Cu amendment on indigenous soil microorganisms were investigated in two soils, a calcareous silty clay (Ep) and a sandy soil (Au), by means of a 1-year field experiment and a two-month microcosm incubation. Cu was added as 'Bordeaux mixture' [CuSO(4), Ca(OH)(2)] at the standard rate used in viticulture (B1=16 kg Cu kg(-1) soil) and at a higher level of contamination (B3=48 kg Cu ha(-1) soil). More extractable Cu was observed in sandy soil (Au) than in silty soil (Ep). Furthermore, total Cu and Cu-EDTA declined with time in Au soil, whereas they remained stable in Ep soil. Quantitative modifications of the microflora were assessed by C-biomass measurements and qualitative modifications were assessed by the characterization of the genetic structure of bacterial and fungal communities from DNA directly extracted from the soil, using B- and F-ARISA (bacterial and fungal automated ribosomal intergenic spacer analysis). In the field study, no significant modifications were observed in C-biomass whereas microcosm incubation showed a decrease in B3 contamination only. ARISA fingerprinting showed slight but significant modifications of bacterial and fungal communities in field and microcosm incubation. These modifications were transient in all cases, suggesting a short-term effect of Cu stress. Microcosm experiments detected the microbial community modifications with greater precision in the short-term, while field experiments showed that the biological effects of Cu contamination may be overcome or hidden by pedo-climatic variations.     

The effects of Brassica green manures on plant parasitic and free living nematodes used in combination with reduced rates of synthetic nematicides

Brassica plants once incorporated into soil as green manures have recently been shown to have biofumigant properties and have the potential of controlling plant-parasitic nematodes. In Washington State, plant-parasitic nematodes are successfully managed with synthetic nematicides. However, some of the synthetic nematicides became unavailable recently or their supply is limited leaving growers with few choices to control plant-parasitic nematodes. The objective of this project was to evaluate the effects of Brassica green manures on their own and in combination with reduced rates of synthetic nematicides on plant-parasitic nematodes and free living nematodes. In a greenhouse experiment and field trials in three seasons, Brassica green manures in combination with half the recommended rate of 1,3-dichloropropene (1,3-D, Telone) reduced root knot nematode, Meloidogyne chitwoodi to below detection levels, and reduced lesion nematodes, Pratylenchus penetrans and stubby root nematodes, Paratrichodorus allius, to below economic thresholds. The combination treatments did not affect the beneficial free-living nematode populations and the non-pathogenic Pseudomonas. The total cost of growing and soil-incorporating Brassica crops as green manures in combination with reduced rates of 1,3-D was approximately 35% lower than the present commercial costs for application for the full rate of this fumigant. Integrating conventional management practices with novel techniques fosters sustainability of production systems and can increase economic benefit to producers while reducing chemical input.     

沙质草地生境中大型土壤动物对土地沙漠化的响应

沙质草地沙漠化过程中土壤动物群落结构变化是沙漠化生物过程中的一个重要方面,对于掌握沙漠化过程中生物退化规律和提出合理沙漠化防治对策具有重要指导作用。选取处于不同沙漠化阶段的流动沙地、半流动沙地、半固定沙地、固定沙地和丘间低地5种生境类型,采用手拣法对其大型土壤动物群落进行了调查。共获得36个动物类群,属于8目32科,优势类群为蚁科,常见类群有22个类群,两个类群的个体数共占群落个体总数的93.33%;稀有类群有13个类群,其个体数占群落个体总数的6.67%。结果显示,丘间低地、固定沙地、半固定沙地和半流动沙地大型土壤动物群落个体数量、类群数和多样性显著高于流动沙地(P<0.05);固定沙地大型土壤动物生物量显著高于其它生境类型(P<0.05);沙质草地严重沙漠化显著地影响大型土壤动物多样性及其生物量。并且,不同土壤动物类群个体对不同沙漠化阶段生境的适应性存在一定差异,产生了不同的响应模式。土壤有机碳和酸碱度以及土壤含水量差异是影响大型土壤动物类群分布与生长的主要因素。研究表明,固定沙地是大型土壤动物的适宜沙地生境,具有较多的个体数量和较高的生物量;丘间低地、半固定沙地、半固定沙地和流动沙地影响大型土壤动物存活,其个体数量和生物量较低。     

Responses of intertidal nematodes to short-term anoxic events

We investigated tolerance to, and activity of, nematodes in hypoxic and anoxic/partially sulphidic conditions and their ability for recovery after reoxygenation of anoxic sediment. To this end, sediments from an intertidal flat were incubated under oxic, suboxic and anoxic/partially sulphidic conditions for a 14-day period and the final density of nematodes, as a group, and of the most abundant species were assessed. In one treatment, oxygen was restored after anoxic incubation. The incorporation of ¹³C, originating from labeled algae added on top of the sediment, was taken as an indication of nematode activity.Short-term suboxic and anoxic/partially sulphidic conditions had similar structuring impact on the nematode community, reducing total densities by about one third. Survival in suboxic and anoxic/partially sulphidic conditions was species-specific. Daptonema setosum, D. tenuispiculum and Chromadora macrolaima, dominant in the oxic incubation, disappeared when the oxygen level was reduced. The density of the other dominant species was slightly reduced (Sabatieria pulchra), similar (Terschellingia communis) or even increased in the suboxic and anoxic conditions (Metachromadora vivipara). The activity level of these three species was, however, reduced under oxygen limitation. Our results are discussed in terms of the life-history strategies of these species.     

Plant injury due to oxygen deficiency in the root environment of soilless culture: A review

The deficiency of oxygen concentration in root environment linked to waterlogging conditions caused important injuries for plants. These effects could be reproduced by oxygen deficient nutrient solution. This bibliographical synthesis has been centered on experimental results obtained on plants cultivated in soilless culture. This review paper presents a methodology used to study oxygen depletion in a nutrient solution and to calculate root respiration rates. The main factors influencing root respiration are reviewed as well as the consequences of oxygen deficiency on roots and shoots functioning. This study would not be complete without some information on the main mechanisms of plant adaptation to oxygen deficiency.