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41.
A bloom of the green microalga Tetraselmis sp. in a small lagoon in Wellington Harbour, New Zealand, is considered to have caused a fish kill of pilchards (Sardinops sagax). The fish deaths are attributed to anoxia brought about by a combination of reduced dissolved oxygen levels and the microalgae sticking to and clogging the secondary gill lamellae of the fish.  相似文献   
42.
采用解剖及石蜡切片技术,观察研究了养殖光唇鱼(Acrossocheilus fasciatus)卵巢发育的形态及组织学结构特征。结果表明,第一次性周期内,4—5月龄鱼卵巢处Ⅰ期,内以第Ⅰ时相卵细胞为主;6—18月龄鱼卵巢处Ⅱ期,内以第Ⅱ时相卵母细胞为主,单层滤泡膜形成;19—20月龄鱼卵巢处Ⅲ期,内以第Ⅲ时相卵母细胞为主,双层滤泡膜及放射带形成,胞质内出现液泡及卵黄粒;21—22月龄鱼卵巢处Ⅳ期,内以第Ⅳ时相卵母细胞为主,胞质内充满卵黄粒;23—24月龄鱼卵巢处Ⅴ期,内以第Ⅴ时相卵母细胞为主,滤泡膜脱落;25月龄鱼卵巢处Ⅵ期,内以空滤泡和第Ⅱ、第Ⅲ时相卵母细胞为主。6—7月为主要产卵期,9月产后卵巢恢复至Ⅱ期,12月进入Ⅲ期,并以该期越冬,4月卵巢重新往前发育。光唇鱼属短期分批产卵类型鱼类。  相似文献   
43.
The reproductive cycle of the dwarf oyster Ostreola stentina (Payraudeau 1826) at Monastir in the south of the Gulf of Hammamet on the east coast of Tunisia was studied using condition indices and histological techniques. The species was shown to be a protandric hermaphrodite. Whereas males dominated the small shell length categories (12.45–34.99 mm), females (21.00–47.16 mm) and hermaphroditic individuals (30.00–57.95 mm) become more predominant with increasing size, suggesting that individuals may undergo protandric development. The overall male to female ratio was 1.0:1.7. Gametogenic development begins in February–March for females and in September for males, and spawning occurs during April and July for females and December and July for males. There was a clear relationship between the gonadal condition index and gametogenic stage for both sexes. Values increased from zero in their early stage of development and peaked during ripe and spawning stages, before decreasing in the spent stage. However, the meat condition index did not show any statistical differences between gametogenic stages.  相似文献   
44.
波纹龙虾雄性生殖系统的解剖学与组织学研究   总被引:1,自引:0,他引:1  
用解剖学和组织学方法研究了波纹龙虾雄性生殖系统,结果表明,波纹龙虾雄性生殖系统由精巢、输精管及生殖孔三部分组成。精巢横切面一般为圆形,外被一层结缔组织被膜,内部为许多圆形或椭圆形的生精小管,生精小管间充满了网状结缔组织。精子的发生经历精原细胞、初级精母细胞、次级精母细胞、精细胞和精子5个阶段。输精管管壁由外到内依次由结缔组织被膜、结缔组织、肌肉层和上皮细胞组成,管壁上的柱状上皮细胞、肌肉组织及结缔组织一起向管内延伸形成纵褶突。管壁和纵褶突上的柱状上皮细胞向管腔中分泌嗜酸性黏液。精荚呈管状,在中段输精管形成,并储存在管腔的黏液中。  相似文献   
45.
半滑舌鳎精子发生的组织学研究   总被引:6,自引:1,他引:5  
本文应用组织学方法对半滑舌鳎雄鱼精巢结构和精子发生过程进行了详细地研究.观察结果表明,它的精巢结构特点是随着精巢的发育可见它的精巢外面有一条管状贮精囊与输出管相连,在精巢发育成熟过程中,贮精囊中逐渐充满精子,这个特点有助于了解半滑舌鳎的受精生物学的复杂性.另外,从半滑舌鳎精子发生过程分析,它的精巢属于小叶型,精巢发育分为6期.精子发生经历精原细胞、精母细胞、精子细胞及精子.最后,文中还讨论了半滑舌鳎精巢中非生殖细胞(间质细胞和Sertoli细胞)的分布及其可能的生理作用.  相似文献   
46.
运用解剖学和组织学方法研究光裸星虫(Sipunculus nudus)消化系统结构。结果表明,光裸星虫消化系统由消化道和直肠盲囊组成,消化道可分为口、食道、下行肠、上行肠、直肠和肛门。口四周由具摄食作用的辐射状触手围绕。消化道管壁由黏膜层、黏膜下层和浆膜三层结构组成,黏膜层具有大量皱褶,黏膜下层和浆膜层中分布有大量颗粒细胞;无连续的肌肉层,只在黏膜下层内散布着数量不等的肌纤维。直肠盲囊细长,连接于上行肠末端,囊壁无分泌细胞,囊内充满黄色黏稠液状物质。  相似文献   
47.
对条纹斑竹鲨(Chiloscyllium plagiosum)的消化器官进行解剖和组织学观察。结果表明,条纹斑竹鲨消化道较短,其长度仅为鱼体全长的49.31%±2.60%。牙细小,三齿头型,多行在使用,每侧有12~14纵行。食道粗短,具有6~8条粗大的纵褶。胃呈"V"型,可分为贲门部和幽门部。小肠可分为十二指肠和回肠,回肠具有18片几乎平行的螺旋瓣。大肠可分为结肠和直肠,均较短。肝脏大,分为左右两叶,左叶较长而宽大,胆囊位于肝左叶近中央背侧,肝脏质量占鱼体质量的4.92%±1.22%。胰脏可分背、腹两叶,胰脏质量占鱼体质量的0.16%±0.04%。条纹斑竹鲨消化系统的组织学特征与其它鱼类基本相似,但大肠上皮为复层扁平上皮,其中含有大量大型粘液细胞。研究表明,条纹斑竹鲨的消化系统具有软骨鱼纲板鳃亚纲的消化系统的基本结构特征,同时又具有自身所特有的与其生活习性相适应的形态结构特征。本研究为条纹斑竹鲨的人工配合饲料的研制和投饵技术提供基础资料。  相似文献   
48.
Structure and function of the digestive system of a bivalve mollusc, Solen grandis, were studied using light microscopy and histochemical methods. The wall of digestive tube consists of four layers: the mucosal epithelium, connective tissue, muscular and fibrosa or serosa (only in the portion of rectum) from the inner to the outer. The ciliated columnar epithelial cells, dispersed by cup-shaped mucous cells, rest on a thin base membrane. There are abundant blood spaces in connective tissue layer. The digestive diverticula are composed of multi-branched duct and digestive tubules. The digestive tubules are lined with digestive and basophilic secretory cells, and surrounded by a layer of smooth muscle fibers and connective tissues. Activities of acid and alkaline phosphatases, esterase and lipase are detected in the digestive cells, and the epithelia of stomach and intestine, suggesting that these cells are capable of intracellular digesting of food materials and absorbing. Besides, acid phosphatase and e  相似文献   
49.
栉孔扇贝(Chlamys farreri)晶杆的形态结构和组织化学研究   总被引:1,自引:0,他引:1  
利用石蜡切片法、扫描和透射电镜技术及组织化学方法,对栉孔扇贝的晶杆进行了研究.晶杆分头部和杆部,横切面呈同轴圆环状,无细胞结构,头部边缘呈溶化状态,内含大量的吞噬细胞和嗜曙红颗粒,杆部表面有球状分泌颗粒.晶杆的电子密度较低,偶尔有带状高电子密度区、电子致密颗粒和电子透明小泡.晶杆内含粘蛋白、酸性粘多糖和蛋白质,无酸性磷酸酶、碱性磷酸酶、脂酶及酯酶活性.栉孔扇贝的晶杆无贮存食物的功能,大小与贝体的性别无关,长时间暴露的在空气中,晶杆消失  相似文献   
50.
Abstract. Samples of Mytilus galloprovincialis and Mullus barbatus were collected in eight coastal sites along the South Adriatic and Ionic coasts of Italy in spring 2000 for a survey of coastal pollution in the Mediterranean basin. Specimens were analysed using an integrated approach based on residue analysis of common aquatic pollutants like organochlorines such as hexachlorobenzene (HCB), DDTs and polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), heavy metals and nonylphenols (NPnE) and biomarker responses such as acetylcholinesterase (AChE) activity, and the two specific P450 activities benzo(a)pyrene monooxygenase (BPMO) and 7-ethoxyre-sorufin-(9-deethylase (EROD). Biological and morphological parameters like somatic liver index (SLI), gonadosomatic index (GSI) and gonadal and gamete histology (eggs and sperms) were also evaluated in red mullet samples. A contamination gradient in which several hot spots occur were revealed in this study. The hot spots account for high levels of organochlorines in both species near incinerators and of PAHs in harbour areas. Levels of both NPnE and AChE activity were highest in two protected marine areas and were within detectable limits in others. This finding was confirmed by P450 activities, in which maximum levels were detected in harbours and protected marine areas. No morphological alterations of male and female gonads were observed on the histological level.  相似文献   
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