香溪河水系大型底栖动物的群落结构及生态位

2005年7月～2006年6月对三峡水库湖北库区最大支流香溪河的大型底栖动物进行定量采集,并对所得数据进行了数理统计分析及生态位分析.结果表明,香溪河水系大型底栖动物物种丰富度在不同季节、不同支流间差异均显著;密度在各季节间差异显著.四节蜉、高翔蜉、锯形蜉、朝大蚊和扁蜉生态位较宽;Tetropina sp.、短尾石蝇、黑蝇生态位较窄.四节蜉、高翔蜉、锯形蜉、朝大蚊与其它分类单元生态位重叠值较大,黑蝇、短尾石蝇、直突摇蚊、Tetropinasp.与其它分类单元生态位重叠值较小.相对丰度和生态位宽度对生态位重

三峡库区四条支流藻类多样性评价及“水华”防治

应用多样性指数、丰富度指数和均匀性指数对长江4条支流水域的藻类多样性进行了评价.比较了4条支流春、秋两季浮游藻类优势种、细胞密度和生物量等指标,对三峡蓄水后库区“水华”成因进行了初步分析.结果表明,4条支流的营养水平均属于中-富营养型,童庄河的水质最差,其次为香溪河和青干河,九畹溪的水质较好.春季硅藻的种类数多,绿藻种类数少;秋季则相反.藻类细胞密度的最高值出现在香溪河(6.036×106个/L),生物量的最高值出现在童庄河(19.997mg/L).2项指标的最低值均出现在九畹溪.在春季,童庄河还出现了拟

饲料质量对丰鲤和奥尼罗非鱼氮及能量收支的影响

实验比较了丰鲤与奥尼罗非鱼摄食低质和高质两种等能饲料时的氮收支和能量收支。低质饲料的蛋白质含量为 34.2 5 %、蛋白质主要来源为豆粕 ,高质饲料的蛋白质含量为 4 5 .4 4 %、蛋白质主要来源为鱼粉。 5 3d的生长结果显示 :摄食低质饲料时 ,奥尼罗非鱼通过降低排泄氮、排泄能和代谢能的比例 ,使生长氮和生长能的比例显著高于丰鲤 ,摄食高质饲料时 ,则通过降低粪氮和粪能的比例取得快速生长的效果 ;丰鲤生长氮和生长能比例不受饲料质量的显著影响 ,但高质饲料使排泄氮和代谢能比例显著降低 ;奥尼罗非鱼的

海峡两岸淡水鱼类分布格局及其生物地理学意义

通过台湾大陆初级淡水鱼类区系的比较分析,将台湾与大陆间的淡水鱼类区系和组成归纳为3种生物地理分布格局:(1)台湾与大陆东南沿海诸水系的淡水鱼类有很高相似性;(2)台湾与东喜马拉雅具有一些相同的淡水鱼类分布;(3)包括台湾岛在内的太平洋西部岛链的淡水鱼类区系之间的相似度很低,这些岛屿与各自相邻大陆的淡水鱼类更相似.从历史生物地理学的角度看,这种分布格局的形成与台湾和大陆古地理、地质的变迁有关.简约分析(PAE)结果认为,以上格局可以用隔离分化的假说加以解释,进一步的研究将使用分子生物地理学方法和手段对海峡两

保安湖麦穗鱼种群生物学V.生产力

在 1 995年 1 0月至 1 996年 1 1月 ,依据有关种群参数估算了保安湖 1 # 试验围拦中麦穗鱼的生产力。月平均瞬时生长率的变化与年龄和季节有关 ,随着年龄增加生长率降低 ,在生活史的早期阶段生长最快 ,生长率一般在春、夏季较高。在研究期间 ,种群平均生物量为1 8 2 7kg·hm- 2 ,周年生产力为 36 53kg·hm- 2 ·a- 1 ,P/B系数为 2 0。 1 996世代对总生产力的贡献为 67 9%。种群月平均生物量及生产力均表现出了较明显的季节变化 ,生物量在秋季(9月 )

中华绒螯蟹幼蟹蜕壳的生态学观察

本文对河蟹幼蟹蜕壳过程及蜕壳后的特征进行了比较详细的观察，并初步探讨了蜕壳与光照、温度及生境的关系对于０．５－２ｇ的幼蟹，蜕壳期大约需要３－６ｈ，软壳期需要２ｈ，薄壳期需要１５ｈ．幼蟹特别喜欢选择有草的生境作为蜕壳地点，也喜欢在池塘浅水区蜕壳，但是在２ｍ以内水深对蜕壳成功率没有影响．蜕壳存在明显的昼夜节律，白天蜕壳的数量显著高干夜间（Ｆ（１．３０）＝ １３. ４， Ｐ＝ ０． ０００９），蜕壳高峰发生在上午（０７： ００－ １１： ００），低谷一般发生在夜间（２３： ００－ ０３：００）．协方差分析（昼夜

鸭儿湖地区六氯环己烷的残留动态与长期归宿

在１９９０—１９９３年期间，研究了历史上曾被ＨＣＨ严重污染的鸭儿湖地区的水生态系统和陆生生态系统中ＨＣＨ的残留动态与归宿，获得了ＨＣＨ在各种不同环境条件下的残留动态方程与环境半衰期．结果表明：鸭儿湖底泥是ＨＣＨ长期残留的主要归宿。尽管ＨＣＨ已禁用十几年，目前该地区环境中ＨＣＨ的残留已降至亚ｎｇ／ｇ级水平，然而它在淡水食物链中仍然存在很高的生物积累．残留的ＨＣＨ在各种环境中的分布和转移均与该地区有机质含量呈正相关。目前环境中ＨＣＨ残留的主要异构体是β-ＨＣＨ。同时各种环境中ＨＣＨ的残留动态可用指数方程来表示

受控生态生保系统中关键生物部件的筛选

生物部件是受控生态生保系统的核心部分 ,筛选的生物部件合适与否在很大程度上决定着试验的成败。为此 ,通过大量实验研究 ,为受控生态生保系统筛选出关键生物物种 1 5个 ,其中高等植物 (蔬菜类 ) 4个 ,微生物 5个 ,微藻 5个 ,低等植物 1个。这些结果为受控生态生保技术实验研究奠定了重要基础

中华双腔吸虫精子的超微结构

利用透射电镜技术，研究了中华双腔吸虫（Ｄｉｃｒｏｃｏｅｌｉｕｍ　ｃｈｉｎｅｎｓｉｓ Ｔａｎｇ ｅｔ Ｔａｎｇ， １９７８）的精子结构，探讨了它与其他复殖吸虫间的异同。结果表明：本种的成熟精于为细线状，共分为头部、中部和尾部，具两根并生的、结构为９＋１的轴丝。细胞核的致密程度有区域上的变化，细胞质较多，电子密度高，具一个线粒体，在单轴丝区域未观察到异常二联管及外周微管。

凤眼莲、水花生若干光合作用参数与酶类的研究

在正常的生长条件下，凤眼莲有较高的叶面系数、叶绿素含量和光合强度。叶片可溶性糖含量也高。在低温胁迫下，凤眼莲和水花生根系活力和过氧化物酶、过氧化氢酶、细胞色素氧化酶、淀粉酶等酶活性均明显下降。试验结果表明，凤眼莲对低温胁迫较水花生更为敏感。

保安湖浮游物和颗粒有机碎屑现存量及季节变动与渔业生产

1987年3月至1988年3月对保安湖所属大湖和桥墩湖浮游物和颗粒有机碎屑现存量作了测定。浮游物平均干重、无灰干重和颗粒有机碎屑量大湖分别为337.6、127.7和96.9t;桥墩湖分别为100.5、50.3和40.2t。浮游物和颗粒有机碎屑现存量具有明显的季节变动。黄丝草、聚草和苦草的碎屑分解对浮游物的形成起着重要的作用。用浮游物碳量估算鲢鳙鱼产潜力大湖为12.3kg/亩;桥墩湖为11kg/亩。

中国淡水鱼类寄生粘孢子虫角形科一新种

<正> 1979年8月25日,我们在江苏省洪泽湖进行鱼类寄生虫区系调查过程中,从岔尾黄颡鱼Pseudobagrus eupogon Boulenger 的胆囊中发现一种粘孢子虫。经鉴定,是属于角形科 Ceratomyxidae角形虫属Ceratomyxa的代表,不仅是科学上的新种,也是角形科角形虫属的种类在我国第一次发现,同时又为该属记录了在淡水鱼类中第二种寄主。 模式标本保存在中国科学院水生生物研究所。

Effects of tetrabrominated diphenyl ether and hexabromocyclododecanes in single and complex exposure to hepatoma HepG2 cells

This study was designed to determine cytotoxic effects of PBDE-47 and HBCDs individually or with a mixture of both compounds exposure to Hep G2 cells. The results showed PBDE-47 and HBCDs induced increase of nitric oxide synthase (NOS) activity, release of NO. dissipation of mitochondria membrane potential and cell apoptosis. Exposure to HBCDs induced ROS formation. Moreover, preincubation with PTIO (NO scavanger) and N-acetylcysteine (ROS scavanger) partially reversed cytotoxic effects of these compounds. The possible mechanism is that PBDE-47 and HBCDs could boost generation of NO and/or ROS, impact mitochondria, and result in start-ups of apoptosis program. Cells exposed to mixture of both compounds and each of them showed non-apoptotic rate significant difference, but the combination of them caused more adverse effects on cells. These results Suggest that PBDE-47 and HBCDs in single and complex exposure have the cytotoxic activity of anti-proliferation and induction of apoptosis in tumor cells in vitro. (C) 2008 Elsevier B.V. All rights reserved.

Microcystin-RR induced apoptosis in tobacco BY-2 suspension cells is mediated by reactive oxygen species and mitochondrial permeability transition pore status

When tobacco BY-2 cells were treated with 60 mu g/mL MC-RR for 5 d, time-dependent effects of MC-RR on the cells were observed. Morphological changes such as abnormal elongation, evident chromatin condensation and margination, fragmentation of nucleus and formation of apoptotic-like bodies suggest that 60 mu g/mL MC-RR induced rapid apoptosis in tobacco BY-2 cells. Moreover, there was a significant and rapid increase of ROS level before the loss of mitochondrial membrane potential (Delta Psi(m)) and the onset of cell apoptosis. Ascorbic acid (AsA), a major primary antioxidant, prevented the increase of ROS generation, blocked the decrease in Delta Psi(m) and subsequent cell apoptosis, indicating a critical role of ROS in serving as an important signaling molecule by causing a reduction of Delta Psi(m) and MC-RR-induced tobacco BY-2 cell apoptosis. In addition, a specific mitochondrial permeability transition pores (PTP) inhibitor, cyclosporin A (CsA), significantly blocked the MC-RR-induced ROS formation, loss of Delta Psi(m), as well as cell apoptosis when the cells were MC-RR stressed for 3 d, suggesting that PTP is involved in 60 mu g/mL MC-RR-induced tobacco cell apoptosis signalling process. Thus, we concluded that the mechanism of MC-RR-induced apoptosis signalling pathways in tobacco BY-2 cells involves not only the excess generation of ROS and oxidative stress, but also the opening of PTP inducing loss of mitochondrial membrane potential. (C) 2007 Published by Elsevier Ltd.

Spatiotemporal heterogeneity of plankton communities in Lake Donghu, China, as revealed by PCR-denaturing gradient gel electrophoresis and its relation to biotic and abiotic factors

The 16S and 18S rRNA genes of planktonic organisms derived from five stations with nutrient gradients in Lake Donghu, China, were studied by PCR-denaturing gradient gel electrophoresis (DGGE) fingerprinting, and the relationships between the genetic diversity of the plankton community and biotic/abiotic factors are discussed. The concentrations of total nitrogen (TN), total phosphorus (TP), NH4-N and As were found to be significantly related (P < 0.05) to morphological composition of the plankton community. Both chemical and morphological analyses suggested that temporal heterogeneity was comparatively higher than spatial heterogeneity in Lake Donghu. Although the morphological composition was not identical to the DGGE fingerprints in characterizing habitat similarity, the two strongest eutrophic stations (I and II) were always initially grouped into one cluster. Canonical correspondence analysis suggested that the factors strongly correlated with the first two ordination axes were seasonally different. The concentrations of TN and TP and the densities of rotifers and crustaceans were generally the main factors related to the DGGE patterns of the plankton communities. The study suggested that genetic diversity as depicted by metagenomic techniques (such as PCR-DGGE fingerprinting) is a promising tool for ecological study of plankton communities and that such techniques are likely to play an increasingly important role in assessing the environmental conditions of aquatic habitats.