主要外来鱼类对千岛湖生态系统的潜在影响及对策

生物入侵已在全球范围内广受关注,外来生物入侵现象日趋严重,不仅导致地区特有物种衰竭,还影响当地生物多样性、生态环境和经济发展。千岛湖(原名新安江水库)作为一个集渔业、水源、旅游、发电于一体的大型山谷型水库,其生态系统状况受到国内外生态学者的普遍关注。然而近年来,该水库也受到外来物种入侵威胁,对土著鱼类尤其是经济鱼类的资源构成了巨大的威胁。综合分析了千岛湖生态系统的主要特征和主要外来鱼种,结合这些外来鱼类的生物学特征,概述主要外来鱼类对千岛湖生态系统的潜在影响,并针对这些潜在风险,提出了相应的治理对策,为千岛湖水域生态系统的管理工作积累基础资料。     

池塘养殖斑鳢弹状病毒的分离与初步鉴定

从患暴发性死亡的斑鳢病灶中分离出一株弹状病毒。 取病鱼肝、脾、肾组织过滤液接种EPC、FHM细胞, 连续传至第3代后28℃培养35h出现细胞病变(CPE), 测得病毒半数细胞感染量为10-5.746/0.1 mL。将病变细胞制成超薄切片, 透射电镜下观察到细胞质中存在大量呈子弹状的病毒颗粒, 大小约53 nm140 nm。用上述组织过滤液及F3代细胞培养病毒液回归感染健康斑鳢均能显示与自然发病鱼相似的症状, 死亡率达100%。根据鳜鱼弹状病毒(Siniperca chuatsi rhabdovirus, SCRV)N蛋白保守序列设计的引物对斑鳢病毒的基因组RNA进行RT-PCR扩增, 得到大小约400 bp的阳性片段。对该片段克隆、测序后与GenBank中序列进行BLAST比对, 发现该基因序列与SCRV同源性最高, 为94%。选取GenBank中已登录的病毒性出血败血症病毒(VHSV)、鳢弹状病毒(SHRV)、鲤春病毒血症病毒(SVCV)、鳜鱼弹状病毒(SCRV)、传染性造血器官坏死病毒(IHNV)、狂犬病毒(RV)、牙鲆弹状病毒(HIRRV)相关序列构建系统进化树, 结果表明, 该基因序列与SCRV聚为一支。由于该病毒粒子的形态大小与SCRV(100 nm200 nm)存在一定差异, 暂将其命名为斑鳢弹状病毒(CHRV)。       

大斑啄木鸟对光肩星天牛幼虫捕食的功能反应和数值反应

光肩星天牛Anoplophora glabripennis（Motsch．）是我国重要林木蛀干害虫,造成了巨大的经济损失（张星耀、骆有庆,2003）。大斑啄木鸟Picoides major（L．）是林业蛀干类害虫的重要天敌,关于啄木鸟对蛀干类害虫的控制作用国内已有一些报道,     

六斑月瓢虫成虫捕食洋槐蚜的功能反应研究

在实验室条件下研究了六斑月瓢虫成虫对洋槐蚜的捕食功能反应,并进行了Holling-Ⅱ型功能反应模型拟合,拟合的圆盘方程为Na=0.9615 Nt/(1 0.00673 Nt),经χ2检验,圆盘方程理论值与实测值相符。六斑月瓢虫成虫的捕食率与个体间相互干扰作用的关系用Hassell模型拟合为E=0.935.P-0.169,其自身密度的功能反应用W att模型拟合为A=109.4.P-0.629。     

乌鳢和斑鳢微卫星制备及其对自交与杂交F1代的初步鉴定

通过磁珠富集法分离了乌鳢(Channa argus)和斑鳢(C.maculate)的微卫星DNA序列,根据这些微卫星DNA序列的两翼序列,采用Primer 3.0或Primer 5.O软件设计出乌鳢与斑鳢的微卫星引物各31对.用62对微卫星引物对乌鳢和斑鳢自交与杂交F1代的4个组合进行扩增,10对引物无扩增产物,其余5...     

外来鱼类革胡子鲶与本地鲶的功能反应及生物学特性的比较

珠江水系是中国遭受外来水生动物入侵最严重的水域之一,分布有许多种外来鱼类,然而这些外来鱼类对本地鱼类资源的影响尚缺乏有效的评估。比较功能反应被认为是量化外来物种生态影响的有效方法之一。本研究采用控制实验对外来鱼类革胡子鲶(Clarias gariepinus)和本地鲶(Silurus asotus)的功能反应进行了比较。实验以鲮(Cirrhinus molitorella)、广东鲂(Megalobrama hoffmanni)和草鱼(Ctenopharyngodon idellus)的幼鱼为饵料,按照1、2、4、8、16和32条的饵料密度进行投喂,设置3个重复组,研究了革胡子鲶和鲶的功能反应类型,建立了功能反应的曲线,并拟合了功能反应的参数;同时分析了革胡子鲶和鲶的食物转化效率并比较了二者的生物学特性。结果表明:革胡子鲶和鲶的功能反应类型均为Type II型。与鲶相比,革胡子鲶具有更高的单位资源消耗率即更强的袭击率(P0.05),而两种鱼对猎物的处理时间则无显著区别(P=0.272);革胡子鲶的食物转化效率显著低于鲶(P0.05),为鲶的0.57倍,两种鱼的相对生长率则无显著差异(P=0.762)。本研究为系统评估革胡子鲶的生态影响提供基础,同时为量化其他外来鱼类的资源消耗率及潜在的生态影响提供借鉴。     

拉萨河流域外来鱼类的分布、群落结构及其与环境的关系

为揭示当前拉萨河流域外来鱼类的现状及其主要影响因素,于2010、2012及2014年对该流域的鱼类群落结构及水体环境进行了调查。共捕获4目6科17属25种鱼类,包括13种外来鱼类和12种土著鱼类。在42个采样点中的19个发现了外来鱼类,包括12处的湿地、6处的河流及1处水库采样点。外来鱼类基本都分布在下游,除了鲫（Carassius auratus）分布到了上游,鲤（Cyprinus carpio）、鳙（Aristichthys nobilis）和泥鳅（Misgurnus anguillicaudatus）分布到了中游。分布最广、数量最多的土著鱼类是拉萨裸裂尻鱼（Schizopygopsis younghusbandi younghusbandi）、东方高原鳅（Triplophysa orientalis）和西藏高原鳅（Triplophysa tibetana）,最常见的外来鱼类为泥鳅、鲫和麦穗鱼（Pseudorasbora parva）。典范对应分析表明,该流域的鱼类群落同时受局域和区域环境因素的作用,二者对鱼类群落变异的总解释量为33.9%。海拔、圆石的比例和沙的比例与鱼类群落结构的关系最为紧密。今后应当开展外来鱼类的监控和清除工作,减少人为活动对河流生态系统的干扰,以促进该地区外来鱼类的防控工作及土著鱼类的保护。     

鱼类嗅觉器官的构造与功能

鱼类的嗅觉器官是其重要的化学感受器之一,由鼻孔、鼻腔和位于鼻腔内的嗅囊构成,鱼类嗅觉器官的进化与发展也经历了一个由低级到高级、由简单到复杂的过程。鱼类的嗅觉器官在鱼类的生活中,诸如摄食、御敌、生殖和集群等行为上发挥着重要的作用。     

小十三星瓢虫对苜蓿斑蚜的捕食功能反应

对小十三星瓢虫Adonia variegata(Goeze)捕食苜蓿斑蚜Therioaphis trifolii(Monell)的研究表明,其功能反应为Holling-Ⅱ型模型,方程为Na=0.967N/(1+0.0095N),捕食苜蓿斑蚜的数量随斑蚜密度增加而增大,日最大捕食量为102头。在10~25℃下,小十三星瓢虫捕食率y与温度x的关系为y=3.4x-7.9375;在25~35℃间的捕食率y与温度x的关系为y=137.08-2.25x。25℃下小十三星瓢虫捕食率最高,捕食率达79.4%。在种内干扰条件下,其捕食作用率E随天敌密度P的增加而减少,干扰反应数学模型为E=0.6063P-0.6743。随着叶片数的增多,小十三星瓢虫和斑蚜之间的距离相对增大,造成捕食率的下降。     

雄性中华乌塘鳢贮精囊的结构与功能

应用组织学、透射电镜及酶联免疫吸附分析法研究了雄性中华乌塘鳢贮精囊的形态结构 ,并探讨其功能。结果表明 ,贮精囊是一对精巢的附属腺体 ,结缔组织隔膜将贮精囊分隔成为许多小室腔。被膜和隔膜中含有平滑肌纤维、毛细血管、成纤维和纤维细胞以及间质细胞。隔膜上排列单层上皮细胞 ,呈柱形、立方形或扁平形 ,生殖季节粗面内质网、管状嵴线粒体和高尔基复合体发达 ,上皮细胞顶部聚集许多无膜包裹的分泌颗粒 ,分泌后细胞器退化 ,胞质中出现大量的大空泡。成纤维细胞具有合成分泌胶原蛋白的结构特征。贮精囊中的间质细胞与精巢中的Leydig型间质细胞形态特征相似。在生殖高峰期不论贮精囊的近端、中央或远端均先后贮存大量的精子 ,混合在分泌物中 ,贮精囊不同小室的上皮细胞发育并不同步。精液加贮精囊液的实验表明 ,贮精囊液有助于增强精子活率和延长精子寿命 ,并能促进受精率的提高。贮精囊纤维丝状分泌物呈深紫红色的PAS阳性反应 ,提示分泌物为粘多糖蛋白 ,贮精囊液含有 17α羟孕酮、PGE2 和PGF2α,能体外诱发雌亲鱼产卵 ,具有性外激素的重要作用     

外来入侵杂草薇甘菊及其伴生种基本光合特性的比较

以ＬＣＡ４光合蒸腾测定测定了植物叶片的气体交换过程。比较报薇基菊与周围其它藤本、草本和阔叶速生木本植物之间光合速率的差异。结果表明：（１）莆匐攀草质一城菊Ｍｍｉｋａｎｉａ ｍｉｃｒａｎｔｈａ具有较高的ＣＯ２固定能力,净光合速率２１．５６μｍｏｌ ＣＯ２ ｍ＾－２ｓ＾－１,高于草质藤本野葛Ｐｕｅｒａｒｉａ ｌｏｂａｔａ（１６．９７）,草质缠绕藤本五爪金龙Ｉｐｏｍｏｅａ ｃａｉｒｉｃａ（１４５５）,与     

ROOT PROFILES AND COMPETITION BETWEEN THE INVASIVE,EXOTIC PERENNIAL,CARPOBROTUS EDULIS,AND TWO NATIVE SHRUB SPECIES IN CALIFORNIA COASTAL SCRUB

The mat-forming succulent, Carpobrotus edulis (Aizoaceae), surrounds and grows over many native plant species in California coastal communities. Two shrub species, Haplopappus ericoides and H. venetus var. sedoides, were found to have shallow root systems that occupied the same soil depths as those of C. edulis. In the presence of C. edulis, the normal rooting profiles of the shrubs were displaced downward, although partial overlap with C. edulis remained. Removal of C. edulis from around individuals of both shrub species resulted in higher predawn xylem pressure potentials in shrubs from the removal treatments as compared to controls, suggesting that the surrounding C. edulis was utilizing water that would otherwise have been available to these shrubs. In H. ericoides, predawn xylem pressure potentials of removal treatment shrubs remained higher than those of the controls throughout the remainder of the dry season even though these shrubs showed a marked increase in canopy area after removal of surrounding C. edulis. Removal of C. edulis from around H. venetus also initially led to higher predawn xylem pressure potentials in the removal shrubs as compared to the controls and increased production of new leaves. After this initial period the predawn xylem pressure potentials of the removal shrubs were not significantly different from those of controls, suggesting that the demand for water by the increased leaf areas eventually matched the enhanced water availability resulting from C. edulis removal. Also, the morphology of H. venetus shrubs changed to that more typical of unaffected individuals. Thus, C. edulis significantly affected not only the water relations of these two shrub species but also their shoot sizes and overall morphologies.     

猕猴前额皮层神经元对信号刺激和无关刺激反应的比较研究

在两只已建立视觉分辨行为以及一只未经训练的猕猴上记录了前额皮层主沟区的单位放电,视觉分辨作业包括下列事件;（1）暗示信号红光（在R模式中）或蓝光（在B模式中）（1.30^s);(2）延缓期（2.10s);（3）反应期出现白光（1.88s)在R模式中动物必需在白光出现后立即拉杆以避免电击在B模式中不给予电击,要求动物不拉杆,共记录了127个前额皮层单位,其中80个单位的放电变化与视觉分辨作业的事件相关,占总数的63%,在测试间歇期内观察了前额皮尾神经元对无关的短声\闪光以及闪烁的红、蓝和白光的反应,总共对96个单位进行了短声和/或闪光刺激的测试,其中23个（24%）对上述刺激产生反应,并大部分（15个）是与行为作业中事件相关的单位,在对103个单位进行闪烁的红、蓝、白光测试中,发现只有12个（12%）单位有反应,在另一只未经训练的猕猴的前额皮层主沟区记录了100个单位,发现只有4个（4%）单位对无关的光刺激有反应,这些光刺激的物理性与上述实验中所采用的刺激相同,以上结果表明,通过学习具有行为意义的刺激能引起更多的前额叶神经元的放电活动,也就是说前额叶神经元对具有行为意义的刺激的反应是在学习过程中形成的,它们的活动是可塑的。     

准大羽羊齿Gigantopteridium中国种与美国种之间的叶结构比较

大羽羊齿植物是一个令人迷惑的类群,这类植物中,Gigantonoclea,Zeilleropteris和Cathaysiopteris是北美和东亚二叠纪植物群共有的3个属,但美国最早发现的大羽羊齿植物Gigantopteridium以前在中国的大羽羊齿植物群中未有确切记录,文中订正和详细描述Gigantopteridium的一个中国种,并对该属中国种的一些相关问题作详尽的讨论,美国大羽羊齿类植物采用小泉源一（Koidzumi,1936),的分类系统,只依据叶脉特征进行分类,它是一人为分类系统（Mamay et al.,1988),根据这一系统,文中涉及的中国和美国标本都应归入Gigantopteridium这一属内,这样,东亚和北美大羽羊齿植物群中的大羽羊齿类植物共同属的数目就由3个增加到4个,在对Gigantopteridium huapingense(Feng)详细描述和订正的基础上,对Gigantopteridium中国种与美国种在叶结构方面的异同进行较为详细的比较,虽然此属目前尚未发现过生殖器官和保存解剖结构的材料。     

CHROMATOGRAPHIC COMPARISON OF DICENTRA SPECIES AND HYBRIDS

Ten species of Dicentra were examined by two-dimensional descending paper chromatography. The flavonoid components, including anthocyanins, formed patterns which were specific to a species or a group of closely related species, and these confirmed certain natural relationships within the genus. Some of the components were hydrolyzed and close structural relationships among them were revealed. They were further characterized by spray reactions and R_F measurements in a variety of solvent systems. The inheritance of the components, especially of the anthocyanins, was studied in the hybrids. All parental substances appeared in some hybrids, but in others some parental components were missing. “Hybrid substances” which had not been present in either parent were found in certain hybrids. This is thought to represent either reconstruction of ancestral biosynthetic pathways, probably through genic complementation, or extension of existing synthetic routes through some type of interaction between parental genomes.     

CHROMATOGRAPHIC COMPARISON OF TRAGOPOGON SPECIES AND HYBRIDS

Approximately 1,700 plants representing five species of Tragopogon (Compositae) and their F₁ and F₂ hybrids were analyzed by two-dimensional descending paper chromatography. Each species, or population within a species, was chromatographically distinct. Often, however, the differences were more quantitative than qualitative. The chromatographic data generally supported the species relationships which had been determined from previous morphologic, hybridization, and fertility studies. Inheritance of the flavonoid compounds was usually additive in the F₁'s. Segregation and recombination of the genes controlling the synthesis of these compounds sometimes approximated 3:1 or 9:7 ratios in the F₂'s. Occasionally parental compounds were missing from some of the hybrids. “Hybrid” compounds which had not been found in either parent were absent from the F₁ but did occur in several F₂ populations. Two linkage groups were present. The first contains genes controlling the synthesis of three compounds and the second, four compounds.     

THE EQUILIBRIA BETWEEN NATIVE AND DENATURED HEMOGLOBIN IN SALICYLATE SOLUTIONS AND THE THEORETICAL CONSEQUENCES OF THE EQUILIBRIUM BETWEEN NATIVE AND DENATURED PROTEIN

The denaturation of hemoglobin by salicylate in neutral solution is completely reversible. There is a mobile equilibrium between native and denatured hemoglobin in neutral salicylate solution. The higher the salicylate concentration the greater is the percentage denaturation. When there is a mobile equilibrium between the native and denatured forms of a protein, denaturation is caused by the addition of any substance which has a greater affinity for the denatured than for the native form. Theoretically the heat of denaturation must vary with the denaturing agent and must depend on the heat of combination of the denaturing agent with the protein.     

DIFFERENTIAL RESPONSES TO MAGNESIUM AND CALCIUM BY NATIVE POPULATIONS OF AGROPYRON SPICATUM

Plants of Agropyron spicatum (Pursh) Scribn. and Smith. from populations native to serpentine and nonserpentine soils were grown at varying levels of magnesium and calcium in culture solutions. The yields of plants from the two populations were different. At high Mg levels (low Ca) the yield of the serpentine population was significantly higher than that of the nonserpentine population. At low Mg the yield of the serpentine population leveled off at a Mg: Ca ratio of 1:2, while the yield of the nonserpentine population increased up to a Mg:Ca ratio of 1:8 and showed no leveling off. Chemical analyses of tissue showed that the Ca uptake of plants from the serpentine population was significantly higher than that of the nonserpentine population. In addition, the serpentine population maintained a lower Mg concentration in the shoots than the nonserpentine population at comparable Mg substrate levels. The two populations showed differences in Ca and Mg uptake efficiency and Mg/Ca, Ca + Mg/K + Na, and Ca + Mg + K + Na in the shoots. The ecotypic differentiation with respect to Mg and Ca between native populations of serpentine and nonserpentine A. spicatum does not appear to be due to any single mechanism but, rather, a combination of several possible mechanisms, i.e., differences in root morphology, uptake mechanisms, translocation of nutrients, and interactions between cations.