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1.
三角鲤的胚后发育过程可分为早期仔鱼、晚期仔鱼和稚鱼3个阶段共11个时期。与其他鲤科鱼类比较,三角鲤胚后发育具卵黄囊吸收迅速、鳔迅速发育成形(巡游模式迅速建立)及鳞片的较早出现、长齐和完成胚后发育时间较短等特点;在水温为25.0±0.7℃的条件下,全长5.2±0.2 mm的初孵仔鱼经过24～26 d的发育,全长达20.6±0.3 mm即完成胚后发育;仔鱼、稚鱼的全长随日龄呈线性生长,相关方程式为L=5.8591+0.6254 A(r=0.999 2,P<0.01),每日增长约为0.63 mm。根据三角鲤胚后发育特点讨论了鱼苗生产应注意的问题。 相似文献
2.
线纹尖塘鳢的胚后发育大致分为仔鱼、稚鱼、幼鱼和成鱼期。初孵仔鱼仅2.875mm。前期仔鱼混合营养期短,仅2～3d。后期仔鱼为器官发育、奇鳍条基本形成期,历时10d,平均全长从4.31mm增至8.97mm。稚鱼为器官分化完毕,奇偶鳍条分节、鳞被形成期,历时27～29d,长至平均全长27.79mm。早期幼鱼鳞被等发育完善,进入生长时期。仔鱼开口饵料为150～200μm轮虫,其摄饵大小与口宽呈正相关。15mm后稚鱼可驯饵摄食人工混合料。对仔、稚、幼鱼的生长测定结果显示,全长与日龄呈线性关系L=0.5289t-0.7354(r2=0.9720),体重与日龄呈指数函数关系,W=0.8236e0.1267t(r2=0.9611),全长与体重呈幂函数关系,曲线回归方程W=0.0045L3.2527,b=3.2527,属匀速生长型。采用池塘培水,添加外源饵料生物系列,稚鱼全长15mm时开始驯饵。2002-2005年共培育全长2.2～3.4cm早期幼鱼523.7万尾,仔鱼培育成15mm稚鱼的成活率为26.8%,培育成早期幼鱼的成活率为75.7%。 相似文献
3.
【目的】探明花鲈(Lateolabrax maculatus)早期主要形态性状对体质量的影响程度,为其良种选育提供参考。【方法】采用数理统计方法对500尾2月龄花鲈的全长(X1)、体长(X2)、体高(X3)、头长(X4)、头高(X5)、躯干长(X6)、吻长(X7)、眼径(X8)、尾柄长(X9)、尾柄高(X10)等10个形态性状和体质量(Y)进行测量分析。【结果】相关性分析结果表明,10个形态性状与体质量的相关性均达到了极显著水平(P<0.01)。通径分析结果发现,体高、全长、眼径、躯干长、吻长、体长等6个性状是影响2月龄花鲈体质量的主要形态性状,其中仅体高对体质量的直接作用大于间接作用,为影响体质量的核心变量。决定系数显示,体高对体质量的单独决定系数最大(0.324),全长和体高对体质量的共同决定系数最大(0.287),6个形态性状对体质量的总决定系数为0.947,表明本研究已将影响2月龄花鲈体质量的主要形态性状全部纳入。经逐步回归分析,拟合得到最优线性回归方程为Y=-1.468+1.314X3+0.160X1-0.307X8+0.149X6+0.305X7+0.046X2。【结论】除体质量外,还须将体高作为花鲈早期选育的目标性状。 相似文献
4.
描记采于贵州省茂兰自然保护区境内一洞穴的中国野鲮亚科(Labeoninae)一新属长臀鲮属Longanalus,spnov和一个新种大鳍长臀鲮Longanalus macrochiroussp nov。新属以臀鳍分枝鳍条为7根等特征,区别于该亚科所有属;新种以偶鳍发达,胸鳍后伸达到腹鳍基,腹鳍后伸超过臀鳍起点等显著特征命名大鳍长臀鲮。 相似文献
5.
【目的】研究弓背青鳉(Oryziascurvinotus)胚胎各阶段的发育特点,观察其自发荧光。【方法】使用正置荧光显微镜对弓背青鳉受精到孵化出膜过程进行连续观察。【结果】弓背青鳉胚胎发育历时10～12d,发育过程分为受精卵激活期、受精卵胚盘形成期、卵裂期、囊胚期、原肠胚期、神经胚期、器官形成期及孵化出膜期共8个时期;根据各时期胚盘形成、体节数量、器官发生、胚体大小和运动等特征的变化,进一步细分为35个阶段。其自发荧光主要开始出现于12肌节期,由虹彩细胞团内的物质在激发光下产生,主要分布于脑与脊索背面的皮肤表层。 相似文献
6.
罗氏沼虾的幼体变态发育需经过多次蜕皮,每次蜕皮均伴随形态及附肢特征的改变。采用显微观测摄像法对Z1-Z12各期幼体样本30尾进行观察测量,结果显示:Z2与Z1在复眼上存在较大的差异;Z3的主要特征为尾节与第六腹节分界;Z4尾扇分为内肢和外肢,均具羽状刚毛;Z5无腹足,尾节狭长,且末端平直;Z6的腹部出现腹足萌芽;Z7腹肢芽延长分为内外肢,Z7与Z8的分期特征主要位于第1触角的内鞭、外鞭的分枝上;Z8的第1、第2对步足具不完全的螯;Z9第1、2对步足具完全的螯;Z10后额角上缘的齿刻增多,Z11第1触角内鞭和外鞭分节数量比Z10多;Z12的形态与成虾相似,额角上、下缘均有齿刻。 相似文献
7.
鞍带石斑鱼人工繁殖及胚胎发育研究 总被引：2，自引：0，他引：2
为建立鞍带石斑鱼(Epinephelus lanceolatus)人工繁殖技术,研究了鞍带石斑鱼亲鱼培育、催产及胚胎发育过程。根据性腺检查及催产结果,判定鞍带石斑鱼在广东的繁殖季节为每年的7-9月份,产卵水温在28~31℃。使用10~12尾雌鱼和3尾雄鱼搭配进行催产实验,亲鱼未出现发情和追尾现象,虽能产卵但均未受精,通过人工授精可得受精卵。对鞍带石斑鱼胚胎发育进行了观察,详细描述从受精卵到初孵仔鱼的28个具体发育时期的形态特征和发育时间,结果表明,将鞍带石斑鱼胚胎发育划分为卵裂期、囊胚期、原肠胚期、神经胚期和器官形成期。在水温(27±0.5)℃、盐度31.0、pH 7.8的海水中,鞍带石斑鱼胚胎历时25 h 40 min完成整个胚胎发育孵化出膜。 相似文献
8.
苏氏圆腹胚胎发育的初步观察 总被引：1，自引：0，他引：1
观察两批苏氏圆腹受精卵的胚胎发育,描述并记录胚胎发育各期的形态特征及发育时间。结果表明:苏氏圆腹成熟卵呈圆球形,淡黄色,富有光泽,卵黄分布均匀,相对密度略大于水,卵径0.93～1.11 mm,平均0.98±0.19 mm。受精卵吸水后呈微黏性,属黏性卵,卵膜略膨胀,卵径0.99～1.15 mm,平均1.08±0.27 mm。苏氏圆腹胚胎发育属于盘状卵裂,与其他淡水硬骨鱼类基本相似。其发育过程可分为:受精卵、卵裂期、囊胚期、原肠期、神经胚期、器官分化期、出膜期和初孵仔鱼。在水温26±1℃的条件下,苏氏圆腹胚胎孵化历时24 h 45 min,总积温640.90 h.℃。初孵仔鱼体全长3.20～3.60 mm。 相似文献
9.
黄土地貌形态特征、发育机理及演化过程等一直是地学研究的热点和前沿。选取黄土高原洛河流域作为研究对象,从坡面尺度、流域尺度、区域尺度分类选取14项地貌因子,较为全面地构建了流域地貌发育形态定量参数体系;提取646个小流域为分析单元,利用主成分分析法,获得了描述流域黄土地貌形态特征的4个主因子;这4个主因子分别反映了4种地貌形态空间格局,即南北渐变型、单中心扩散型、东西过渡型、多中心扩散型。结合流域地貌类型和地貌发育程度特征,认为黄土地貌地形起伏和垂直侵蚀特征反映了研究区的总体地貌空间格局,洛河流域黄土地貌主要是在多种因素影响下,随着水系由下游向上游不断地溯源侵蚀、下切扩展,最终形成了现今形态空间分异格局。 相似文献
10.
【目的】研究云纹石斑鱼(♀)×蓝身大斑石斑鱼(♂)杂交子代胚胎发育与仔稚幼鱼生长特征。【方法】通过干法人工授精将云纹石斑鱼(♀)×蓝身大斑石斑鱼(♂)进行种间杂交,连续取样观察和系统记录杂交子代的胚胎发育过程和仔稚幼鱼期的生长发育和形态变化,同时培育云纹石斑鱼纯种进行比较。【结果与结论】杂交子代受精卵发育经过卵裂期、囊胚期、原肠胚期、神经胚期、器官形成期及出膜期,历时31 h 30 min完成胚胎发育。杂交子代的受精率为89.57%,孵化率为75.68%,受精率、孵化率均低于对照组(91.13%和87.59%);畸形率为24.55%,高于对照组(17.88%)。依据卵黄囊、背鳍第二鳍棘和腹鳍棘的伸长与收缩、体色的变化、鳞片的出现等特征将胚后发育分为仔鱼、稚鱼、幼鱼3个时期。孵化后33d仔鱼进入稚鱼期,孵化后60d稚鱼变态为幼鱼。与云纹石斑鱼纯种比较,杂交后子代生长快于后者,220日龄杂交子代全长(18.81±1.585)cm,体质量(9 173.42±3.537)g,均高于同期云纹石斑鱼纯种[全长(16.35±1.416)cm,体质量(110.80±2.379)g],杂交后代体色一致性较高,有明显的生长优势。 相似文献
11.
WANG Xichang Yutaka Fukuda CHEN Shunsheng Masahito Yokoyama CHENG Yudong YUAN Chunhong QU Yinghong Morihiko Sakaguchi 《中国海洋大学学报(英文版)》2005,4(3):229-233
According to the three-dimensional contour maps showing the gel-forming properties of surimi derived from freshwater fish, 8 species of surimi were classified into two types. The-valley type surimi （silver carp, big-head carp, Chinese snake head and blunt snout bream） shows easy setting, low resistance to gel collapse, high enhancement ability with two-step heating, and narrow optimum heating temperature and time area, which are of the same characteristics as the walleye pollack surimi. In contrast, the Plateau type surimi （tilapia, grass carp, mud carp and common carp） exhibits difficult setting, high resistance to gel collapse, no enhancement ability with two-step heating, and wide optimum heating temperature and time area. There are seasonal changes of gelling properties of silver carp surimi, and the setting ability of surimi gel is higher in winter and lower in summer. The marine fish meat gels and the freshwater fish meat gels have the same acceptability for inland Chinese according to the sensory evaluation results. A slight increase in sensory scorings of kamaboko gels occurred when the extract from walleye pollack muscle was added, especially in the odor scoring of silver carp kamaboko gels. 相似文献
12.
Study of the feeding capacity of silver carp and bighead carp by means of experimental ecologyshowed that the filtering frequency of silver carp was slightly greater than that of bighead carp,but thatthe latter's suction volume was much greater than the former's so the filtering rate(filtering frequency mul-tiplied by the suction volume)of silver carp was smaller than that of bighead carp.The filtering efficien-cy of silver carp for phytoplankton was greater than that of bighead carp for them.The removal ratesof silver carp for phytoplankton were greater than those of bighead carp,but for zooplankton the formerwere smaller than the latter.For food particles about 70 μm both removal rates were almost equal.The feeding habits of the two species in natural waters is also discussed in the paper. 相似文献
13.
海底泥底辟(泥火山)与周缘发育的天然气水合物存在着密切的关联,表现在静态要素和动态成藏2个方面。作为一种重要而有效的运移通道类型,泥底辟(泥火山)携带的气体将是天然气水合物的重要气体来源。同时,含气流体沿着泥底辟(泥火山)的上侵,可能会导致上覆地层中温压场和地球化学组分的改变,进而引起天然气水合物稳定带厚度的变化。因此,泥底辟(泥火山)将控制天然气水合物的成藏,如位于构造中心部位的矿物低温热液成藏模式和位于构造边缘的矿物交代成藏模式。另一方面,泥底辟(泥火山)的不同演化阶段将对天然气水合物的形成和富集产生不同的影响。早期阶段,泥底辟(泥火山)形成的运移通道可能并未延伸到天然气水合物稳定带,导致气源供给不够充分;中期阶段,天然气水合物成藏条件匹配良好,利于天然气水合物的生成;晚期阶段,泥火山喷发带来的高热量含气流体引起天然气水合物稳定带的热异常,可能导致天然气水合物的分解,直至泥火山活动平静期,天然气水合物再次成藏。 相似文献
14.
EFFECT OF SULPHATE-REDUCING BACTERIA ON ELECTRO-CHEMICAL CORROSION BEHAVIOR OF 16Mn STEEL IN SEA MUD
ＩＮＴＲＯＤＵＣＴＩＯＮＩｔｗａｓｇｅｎｅｒａｌｌｙｃｏｎｓｉｄｅｒｅｄｐｒｅｖｉｏｕｓｌｙｔｈａｔｔｈｅｃｏｒｒｏｓｉｏｎｏｆｓｔｅｅｌｉｎｓｅａｍｕｄｗａｓｎｏｔｓｅｒｉｏｕｓ.Ｈｏｗｅｖｅｒ,ｉｔｗａｓｌａｔｅｒｆｏｕｎｄｔｈａｔｔｈｅｃｏｒｒｏｓｉｏｎｒａｔｅｏｆｓｔｅｅｌｉｎｓｏｍｅｓｅａｍｕｄｗａｓｈｉｇｈｅｒｔｈａｎｔｈａｔｉｎｓｅａｗａｔｅｒ(Ｋｉｎｇ,1980;Ｓｅｈｍｉｄｅ,1982;Ｇｕｏｅｔａｌ.,1997;Ｈｏｕ,1998).Ｔｈｅｒｅａｒｅｓｏｍｅｒｅｐｏｒｔｓｔｈａｔｔｈｅｃｏｒｒｏｓｉｏｎｒ… 相似文献
15.
以宜来高速湾潭隧道为研究对象, 通过现场调查、地下水示踪实验、地下水流量监测, 以及采用大气降雨入渗法计算隧道的平均涌水量和丰水期涌水量, 同时采用RFPA渗流软件对隧道涌突水的可能性进行判别。现场调查及示踪试验结果显示湾潭隧道岩溶管道为多支, 混合型岩溶管道, 水文地质条件复杂, 丰水期涌水量约为平均隧道涌水量的4.6倍。数值模拟结果表明, 隧道涌水突泥破坏要历经裂隙萌生、裂隙扩展、裂隙进一步扩展、贯通破坏阶段。同时当岩溶管道处的过水流量达到初始值(37 248 m3/d)约2.7~3.5倍之间时便可出现涌水突泥破坏, 也即出水口2流量达到10 000~13 000 m3/d时, 湾潭隧道具有极高的涌水突泥风险。 相似文献
16.
建鲤与黄河鲤的RAPD分子标记及其杂交优势的遗传分析 总被引：3，自引：0，他引：3
利用RAPD技术对建鲤、黄河鲤及其杂交子代进行了遗传分析,筛选的33个引物共扩增出155条带,其中多态性片段为105条,片段S18-1600、S472-300具有种的特异性,可作为鉴别建鲤与黄河鲤的分子遗传标记。建鲤、黄河鲤及其正、反交子代群体内的遗传相似系数分别为0.8240、0.7921、0.7920、0.8569,黄河鲤与正交F1具有较高的遗传变异水平,反交F1变异最小。正交F1、反交F1与亲本(建鲤、黄河鲤)的遗传距离分别为0.2233、0.2436、0.1749、0.2026,说明子代均继承了较多的建鲤的遗传物质。分析了子代与亲本的RAPD标记类型以及各类型的条带数。应用PIT标记系统测定了子代的杂种优势并探讨了优势产生的遗传机理。 相似文献
17.
18.
Impact of the Three Gorges Dam on reproduction of four major Chinese carps species in the middle reaches of the Changjiang River 总被引：1，自引：0，他引：1
Silver carp (Hypophthalmichthys molitrix), bighead carp (Aristichthys nobilis), grass carp (Ctenopharyngodon idella), and black carp (Mylopharyngodon piceus) are the four major Chinese carps and are commercially important aquaculture species in China. Reproduction of these carp has declined since the construction of the Three Gorges Dam (TGD) due to an altered water flow and thermal regime in the Changjiang (Yangtze) River. However, details of the changes in reproduction of the four species are not well understood. To assess the impact of the TGD on reproduction of the four carp, we investigated their eggs and larvae at Yidu City, which is 80 km below the TGD, during 2005–2012. We examined diff erences in larval abundance of the four species in the Jianli section (350 km downstream of the TGD) before (1997–2002) and after (2003–2012) construction of the TGD. Based on these observations, the first spawning date of the four species was delayed a mean of about 25 days after the dam was constructed. Mean egg abundance in the Yidu section of the river was 249 million and mean larval abundance was 464 million, which were significant decreases since the 1980s. Moreover, larval abundance in the Jianli section after the dam was constructed was significantly lower than that before construction (ANCOVA, P<0.05). The observed larval abundance accounted for only 24.66% of the predicted value in 2003 when the dam was first inundated. The present spawning grounds between the TGD and Yidu section of the river are very similar to those described in the 1980s, and some spawning grounds exist upstream of the TGD. Large free-flowing stretches upstream of the TGD and the creation of artificially flooded downstream reaches are needed to stimulate spawning and eff ectively conserve these four major Chinese carps species. 相似文献
19.
On the origin of rice agriculture in southern China and its propagation in East Asia 总被引：1，自引：0，他引：1
Zhenguo Huang 《中国地理科学(英文版)》1994,4(4):289-294
Based on the archaeological rice cultivation with the14C dating of about 4000–5000 a B.P. the author holds that the plain at the lower reaches of the Changjiang (Yangtze) River
is one origin of rice cultivation in Asia and the other is Allahabad of India. The propagation of ancient rice cultivation
in China can be divided into three stages, namely 4000–3000, 2635–2420 and about 1000 a B.P. It is inferred that there were
two ways for propagating rice cultivation from China to Japan. One was from lower reaches of Changjiang River to Kyushu by
sea way and the other was from Shandong Peninsula to southern Korea and then to Kyushu. The age of propagating rice cultivation
into Vietnam from South China is about 1000 a B.P. Being influenced by climatic changes since about 5000 a B.P. the propagation
of rice cultivation was stagnated for two times at least, for example, the three warm climatic stages and the two cold stages
were quite in correspondence with the propagation and stagnation stages of rice cultivation, respectively, in China. During
the ancient times the development of paddy rice was directive related to the fluctuation of sea level which is in keeping
with the climatic changes. 相似文献
20.
以苏州城北路人民路段综合管廊矩形顶管工程为例，分析了影响矩形顶管顶进力的关键因素，提出了管节配重、管节涂蜡和管节注浆等综合减阻方法以降低管壁摩阻力。在管节内放置重物平衡管节所受周围泥浆的浮力；通过涂蜡和喷蜡使管壁光滑，降低管壁与周围介质的摩擦系数；选择合适的材料和配比配制适合地层的泥浆，调整注浆量和注浆压力，使管节周围形成完好的泥浆套。基于实测顶进力与理论计算值的对比分析表明，管壁单位面积摩阻力降低了40%左右，证实该综合减阻方法解决了人民路段矩形顶管顶进力过大的问题。 相似文献