长江中游鱼类资源量的估算

为了解长江中游的鱼类资源现状,于2018年5和6月以及9和10月在宜昌、石首、洪湖、武汉和湖口5个江段进行了渔获物调查工作。通过统计各江段的渔业捕捞情况,计算年捕捞量。用体长股分析方法,对铜鱼(Coreius heterodon)、鳊(Parabramis pekinensis)和瓦氏黄颡鱼(Tachysurus vachelli)的资源量进行估算,并以此推算各江段的鱼类总资源量。结果显示,宜昌江段的鱼类年总资源量1077.36 t,其中,铜鱼为623.25 t;石首江段的年总资源量为2190.74 t,铜鱼为698.19 t;洪湖江段的鱼类年总资源量为58.57 t,其中,瓦氏黄颡鱼为0.41 t;武汉江段的鱼类年总资源量1010.54 t,其中,鳊为148.65 t;湖口江段的年鱼类总资源量14.55 t,瓦氏黄颡鱼为0.032 t。估算结果可以为长江中游鱼类资源保护措施的制定提供数据参考。     

长江上游特有种长鳍吻鮈种群数量和资源利用评估

长鳍吻鮈(Rhinogobio ventralis)为长江上游特有种,由于过度捕捞和大坝建设,其种群生存受到极大威胁。为了解三峡工程蓄水后、金沙江一期工程蓄水前该物种的种群动态,作者利用2007–2009年长江上游江津和宜宾江段调查获取的体长频率数据,评估了其生长和死亡参数、种群数量及资源利用情况。结果表明,长江上游长鳍吻鮈渔获群体体长范围为52–250 mm,体重范围为2.7–307.2 g,平均体长为150.8±40.7 mm,平均体重为72.3±49.7g。江津江段长鳍吻鮈平均体长(168.6±29.5 mm)显著大于宜宾江段(125.6±41.2 mm)。长鳍吻鮈体长–体重关系为:W=6.06×10~(–6)L~(3.20)(R~2=0.98,P0.01,n=436)。由体长频率法拟合出渐近体长(L_∞)为338 mm,生长系数(k)为0.24/yr。由Pauly公式、Gunderson和Dygert公式、Jensen公式等3种方法估算出其平均自然死亡系数为0.43。由长度转渔获物曲线估算出江津和宜宾江段长鳍吻鮈的总死亡系数分别为2.26和2.09。江津和宜宾江段长鳍吻鮈资源开发率分别为0.81和0.79,已超过由Beverton-Holt动态综合模型估算出的最大开发率0.57和0.62。由体长实际种群分析估算出2007、2008和2009年江津江段长鳍吻鮈种群数量分别为68,247、67,432和176,266尾,平均为103,982尾;宜宾江段种群数量分别为22,953尾、46,340尾和34,021尾,平均为34,438尾,表明江津江段种群数量高于宜宾江段。长鳍吻鮈资源已被过度开发,建议加强种群动态监测,延长禁渔期及开展栖息地修复等措施保护这一特有物种。     

葛洲坝下游江段中华鲟产卵场食卵鱼类资源量估算

为定量评估食卵鱼类对中华鲟资源的危害,1997－2001年间,对中华鲟产卵场所在的葛洲坝水利枢纽坝址至下游庙嘴之间长约5km的江段,进行了渔业捕捞样本抽样和解剖检测,运用体长股分析方法并结合淦获物中不同种类的相对数量比例估算出食卵鱼类资源量,研究结果表明,吞食中华鲟卵的主要有圆口铜鱼,铜鱼,瓦氏黄颡鱼等11种鱼类,其年度资源量为197487－744487尾,多年平均444822尾。     

长江上游江津江段长薄鳅种群参数和资源量评估

长薄鳅(Leptobotia elongata)为长江上游特有种,由于过度捕捞和大坝建设,其种群生存受到极大威胁,已被《中国物种红色名录》列为易危物种。为了解三峡工程蓄水后该物种的种群动态,利用2007~2009年三峡库区以上江津江段的渔获量和体长频率数据评估了其生长和死亡参数、资源量及资源利用。长江上游江津江段长薄鳅体长范围为76~480 mm,体重范围为5~2 002 g,平均体长为(158.7±54.8)mm,平均体重为(72.4±148.8)g。优势体长组为90~210 mm,约占总数的77.9%(n=277)。长薄鳅体长(L,单位mm)与体重(W,单位g)幂函数关系为:W=7.28×10﹣6L3.09(R~2=0.95,P0.01,n=277)。由体长频率法拟合出长薄鳅渐近体长(L_∞)为555 mm,生长系数(k)为0.17/a。由Pauly经验公式估算出其自然死亡系数(M)为0.37。由长度转渔获物曲线估算出其总死亡系数(Z)为1.23。江津江段长薄鳅资源开发率为0.70,超过了其资源最大开发率0.43,表明其资源已过度开发。由体长结构实际种群分析估算出江津江段2007、2008和2009年长薄鳅年资源量分别为2 544尾/km(0.75 t/km)、2 405尾/km(0.42 t/km)和7 245尾/km(1.63 t/km),平均4 065尾/km(0.93 t/km)。与以往研究相比,本研究记录到了长薄鳅的最大个体(体长480 mm);本研究估算的长薄鳅总死亡系数和资源开发率较高,可能与江津江段的捕捞强度较高有关。建议加强长薄鳅种群动态长期监测,采取禁渔、人工增殖放流等措施促进资源恢复。     

长江上游三层流刺网渔业现状的调查

1997-1999年对长江上游宜宾江段和合江江段的三层流刺网渔业现状进行了调查。合江江段三层流刺网内网目在10-180mm之间,宜宾江段以50mm以下的网目为主。采集到的鱼类有59种,包括17种长江上游特有鱼类;渔获物组成存在区域、季节和年际之间的差异。目前长江上游的捕捞强度比70年代显著提高。     

长江宜宾江段铜鱼属鱼类种间食物关系

采用碳、氮稳定同位素技术对2012年4-5月长江宜宾江段铜鱼和圆口铜鱼的食物组成进行了分析,并利用多元统计分析方法探讨了铜鱼和圆口铜鱼种间食物关系,包括饵料相似性指数、重叠系数及2种鱼的摄食器官形态差异对食物组成的影响.结果表明:1)铜鱼的δ13C和δ15N变化范围分别为-21.15‰～-20.31‰和9.67‰～ 10.21‰,为偏动物性的杂食性鱼类;圆口铜鱼的δ13C和δ15N分别为-23.30‰～-21.18‰和7.40‰～ 9.21‰,相对铜鱼为偏植物性的杂食性鱼类,铜鱼和圆口铜鱼均与传统肠含物分析的结果存在一定的差异;2)两种鱼的食物相似性指数和食物重叠系数分别为78.7％和55.6％;3)主成分分析(PCA)表明,铜鱼和圆口铜鱼摄食器官形态特征存在一定的差异.长江宜宾江段铜鱼和圆口铜鱼种间竞争不激烈,作为向家坝蓄水前最后一次对长江宜宾江段铜鱼和圆口铜鱼食性及种间食物关系的调查,研究结果可为分析向家坝蓄水对宜宾江段鱼类营养结构的影响提供数据参考.     

长江宜昌江段三层流刺网对鱼类资源影响的分析

利用2004~2009年长江宜昌江段三层流刺网的渔获物数据,分析三层流刺网的主要捕捞对象和个体大小,探讨三层流刺网对长江鱼类资源的影响。结果显示,采集到5目8科40种鱼类,主要捕捞对象为铜鱼、圆口铜鱼、瓦氏黄颡鱼、长吻鮠和圆筒吻鮈等喜流水的种类。三层流刺网主要捕捞对象的体长明显小于初次性成熟体长。本研究的分析结果说明三层流刺网的主要捕捞对象为喜流水、中下层鱼类的幼鱼,对鱼类资源造成了过度捕捞。为了保护长江鱼类资源,建议在长江水系开展全面禁渔。     

长江上游朱杨溪江段圆筒吻鮈种群参数和资源量

圆筒吻鮈为长江上游特有种,三峡、向家坝、溪洛渡等梯级水利工程的建设,可能对其物种生存产生较大影响。为了解三峡工程蓄水后、金沙江一期工程蓄水前该物种的种群动态,2007-2009年对长江上游朱杨溪江段的圆筒吻鮈进行了调查,利用体长频率数据对其种群参数和资源量进行了估算。长江上游朱杨溪江段圆筒吻鮈渔获群体体长范围为69.0-268.0mm,体重范围为3.9-230.4 g,平均体长为(181.4±26.9)mm,平均体重为(78.5±33.0)g;优势体长组为125.0-225.0 mm,约占总数的93.0%。圆筒吻鮈体长体重关系为:W=1.58×10~(-5)L~(2.95)(R~2=0.94,P0.01,n=401),为匀速生长类型,可用Von Bertalalfffy生长方程描述其生长规律。圆筒吻鮈生长参数为,L_∞=361 mm、k=0.21a~(-1)、t_0=-0.68;死亡系数为Z=1.70、M=0.50、F=1.20。其开捕体长为163.4 mm资源开发率为0.70超过了其资源最适开发率(0.60)而接近最大开发率(0.75)。2007-2009年朱杨溪江段圆筒吻鮈年渔获量分别为6716尾(0.50t)、22772尾(1.87 t)和16139尾(1.20 t),平均值为15209尾(1.19 t)。由体长股分析法估算出2007-2009年朱杨溪江段圆筒吻鮈年资源量分别为16361尾/km(1.25 t/km)、13922尾/km(1.74 t/km)和26836尾/km.(1.93 t/km)均值为19040尾/km(1.64 t/km)。目前圆筒吻鮈资源开发率偏高,建议提高开捕体长至193.5 mm,降低其开发率。建议逐步引导渔民转产转业,实施全年禁渔措施,加强筒吻鮈等特有鱼类的保护。     

向家坝和溪洛渡蓄水对圆口铜鱼不同年龄个体下行移动的影响

拦河筑坝所导致的物理阻隔和生态阻隔是影响鱼类迁徙的关键因素。圆口铜鱼Coreius guichenoti(SauvageDabry de Thiersant,1874)作为长江上游重要的河流性洄游鱼类,其迁徙不可避免受到金沙江下游向家坝和溪洛渡大型水电站蓄水的影响。关于向家坝和溪洛渡蓄水是否会显著阻隔圆口铜鱼个体的下行以及不同年龄个体之间受阻隔的影响是否存在差异,迄今为止,还未有相关报道。本文拟通过2012—2014年对长江上游永善江段和宜宾江段圆口铜鱼年龄结构变动的研究,探讨向家坝和溪洛渡蓄水对圆口铜鱼不同年龄个体下行阻隔的影响程度。结果表明:1)向家坝和溪洛渡蓄水对圆口铜鱼下行产生了明显的阻隔效应;2)向家坝和溪洛渡蓄水对1龄个体的下行阻隔最明显且最严重;3)与单一的大型水库和大坝相比,多个梯级的大型水库和大坝会对圆口铜鱼的下行产生更为严重的阻隔效应。本文拟为金沙江下游圆口铜鱼的资源保护提供基础数据支持。     

长江中、上游铜鱼的生长特性

铜鱼是长江中上游的重要经济鱼类和天然捕捞对象,1990—1995年作者利用在长江中上游收集的1030尾标本,对铜鱼的生长特性进行了研究。其体重和体长的关系为W=0.005413L~(3.113)(r=0.9982),生长方程为L_t=60.0229[1-e~(-0.2325(t 0.6108))];W_t=3261.9137[1-e~(-0.2325(t 0.6108))]~(3.113),体重生长拐点t=4.2龄,相应的体长41.05cm、体重973.03g。按生长指标值分析,阶段生长可明显地划分为两个时期,即4龄前的生长迅速期和4龄后的生长减缓期。因此,天然渔业的捕捞规格应控制在约1000g以上的个体,目前在葛洲坝以下的中游江段主要捕捞幼鱼的现状应该改变。     

Photoregulation of seed germination of wild-type and of an aurea-mutant of tomato

Seed germination of an aurea mutant of tomato ( Lycopersicon esculentum Mill.) is promoted by continuous irradiation with red, far-red or long-wavelength far-red (758 nm) light as well as by cyclic irradiations (5 min red or 5 min far-red/25 min darkness). Far-red light applied immediately after each red does not change the germination behaviour. Seed germination of the isogenic wild-type, cv. UC-105, is promoted by continuous and cyclic red light while it is inhibited by continuous and cyclic far-red light and by continious 758 nm irradiation. Far-red irradiation reverses almost completely the promoting effect of red light. The promoting effect (in the aurea mutant) and the inhibitory effect (in the wild-type) of continuous far-red light do not show photon fluence rate dependency above 20 nmol m⁻² s⁻¹. It is concluded that phytochrome controls tomato seed germination throgh low energy responses in both the wild type and the au mutant. The promoting effect of continuous and cyclic far-red light in the au mutant can be attributed to a greater sensitivity to P_fr.     

六种藓类植物茎的比较解剖学研究

通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.     

真菌类遗传学分析的知识结构教学

本文以认知结构理论为指导,讨论了真菌类遗传分析与高等动植物遗传分析的内在联系,认为利用这种内在联系进行教学可收到好的效果并说明了作者的具体教学过程。 Abstract:In the paper, the relationship between genetic analysis of Fungi and genetic analysis of high animal and plant was discussed.A good results were obtained when we adopted this method in the teaching.     

Interconnection of parameters of regulation system of lipid peroxidation and of morphophysiological parameters of mouse liver

A complex analysis of seasonal fluctuations of the mean group parameters of the system of regulation of lipid peroxidation has been performed in liver of Balb/c mice. Association of lipid characteristics and morphophysiological parameters is studied in the Balb/c mouse liver. An inter-connection is revealed between the liver index and the amount of lysoforms of phospholipids, the scale and character of the interconnection differing essentially depending on proportion of phos-phatidylcholine in mouse liver phospholipids.     

History of the discovery of the mode of transmission of yellow fever virus

This essay documents and examines the historical circumstances and events surrounding the discovery of the mode of transmission of yellow fever virus in Cuba. Close scrutiny of the articles published by Walter Reed and his colleagues in 1900, 1901 and 1902 reveals their limitations as historic documents. Fortunately, other sources of information from that period survive in letters and documents written by individuals involved in the quest for the mode of transmission. Examination and comparison of those sources of information unveiled a fascinating story which reveals that misunderstandings engendered by published articles accorded merit where it was not fully due.     

Physiological characteristics of various species of strains of carboxydobacteria

Seven strains of aerobic carbon monoxide-oxidizing bacteria (carboxydebacteria) when growing on CO as sole source of carbon and energy had doubling times which ranged from 12–42 h. The activity profiles obtained after discontinuous sucrose density gradient centrifugation indicated that the CO-oxidizing enzymes are soluble and the hydrogenases are membrane-bound in all strains examined. The CO-oxidizing enzymes of Pseudomonas carboxydohydrogena, Pseudomonas carboxydoflava, Comamonas compransoris, and the so far unidentified strains OM2, OM3, and OM4 had a molecular weight of 230,000; that of Achromobacter carboxydus amounted to 170,000. The molecular weights of the CO-oxidizing and H₂-oxidizing enzymes turned out to be identical. The cell sonicates were shown to catalyze the oxidation of both CO and H₂ with methylene blue, thionine, phenazine methosulfate, toluylene blue, dichlorophenolindophenol, cytochrome c or ferricyanide as electron acceptors. Methyl viologen, benzyl viologen, FAD⁺, FMN⁺, and NAD(P)⁺ were not reduced. The spectrum of electron acceptors was identical for all strains tested. Neither free formate, hydrogen nor oxygen gas were involved in the CO-oxidation reaction. Methylene blue was reduced by CO at a 1:1 molar ratio. The results indicate that CO-oxidation by carboxydobacteria is catalyzed by identical or similar enzymes and that the reaction obeys the equation CO+H₂OCO₂+2H⁺+2e^- as previously shown for Pseudomonas carboxydovorans.Dedicated to Otto Kandler remembering almost three decades of enjoyable cooperation     

Modulation of allostery of pyruvate kinase by shifting of an ensemble of microstates

Since the introduction of the concepts of allostery about four decades ago, much advancement has been made in elucidating the structure-function correlation in allostery. However, there are still a number of issues that remain unresolved. In this review we used mammalian pyruvate kinase (PK) as a model system to understand the role of protein dynamics in modulating cooperativity. PK has a triosephosphate isomerase (TIM)(α/β)₈ barrel structural motif. PK is an ideal system to address basic questions regarding regulatory mechanisms about this common (α/β)₈ structural motif. The simplest model accounting for all of the solution thermodynamic and kinetic data on ligand-enzyme interactions involves two conformational states, inactive E^T and active E^R. These conformational states are represented by domain movements. Further studies provide the first evidence for a differential effect of ligand binding on the dynamics of the structural elements, not major secondary structural changes. These data are consistent with our model that allosteric regulation of PK is the consequence of perturbation of the distribution of an ensemble of states in which the inactive E^T and active E^R represent the two extreme end states. Sequence differences and ligands can modulate the distribution of states leading to alterations of functions. The future work includes: defining the network of functionally connected residues; elucidating the chemical principles governing the sequence differences which affect functions; and probing the nature of mutations on the stability of the secondary structural elements, which in turn modulate allostery.     

（鱼句）亚科花（鱼骨）型鱼类骨骼系统的比较

对我国花型Hemibarbuspattern鱼类作了骨骼系统比较,结果表明,此类型鱼类脑颅较长,副蝶骨平直或稍弯曲,眶蝶骨腹纵嵴发达(铜鱼Coreius septentrionalis例外),下颞窝和咽突中等大,基枕骨后突发达;脑颅中的上筛骨的后突、侧筛骨的外筛突,蝶耳骨的外突、上耳骨的后突、围眶骨和后颞窝等均有明显的差异;咽颅中的舌颌骨、尾舌骨、鳃盖骨和下咽齿的列数等又有显著的区别;附肢骨骼中的腰带骨、脊椎骨中的复合神经骨和第4椎骨腹侧的悬器等也有不同之处。据此,这些差异和区别可作为属间或种间的分类依据。