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1.
The development of the anther wall follows Basic-type. The cytokinesis at the time of pollen mother cell meiosis conforms to successive type. The arrangement of the microspores in the tetrad is referred to isobilateral. The primary wall between the generative cell and the vegetative cell is callose. The callose wall is easily detected under the fluorescence microscope. The mature pollen grain is 2-celled type. The ovule is bitegminous, tenui-nucellar and anatropous. The development of the female gametophyte follows Fritillaria-type. The mature embryo sac. consists of the six cells including the seven nuclei. The fertilization is referred to the premitotic syngamy type. The fusion of the female and male nucleoli is not observed at the end of the fertilization. The division of the primary endosperm nucleus is earlier than that of the zygote. The development of the endosperm is referred to nuclear type. The division of the zygote is transverse of longitudinal, the development of the embryo conforms to Onagradtype. When the seed is mature, the embryo is at the proembryo stage without differentiation and the endosperm cells are not absorbed.  相似文献   

2.
本文详细描述了菱臼齿兽耳区各个部分的基本结构;并指出了耳区结构与某些啮齿类的相似性,以及中耳鼓泡组成成份与戈壁(犭亚)兽(Anagale gobiensis)的区别。  相似文献   

3.
本文就以下几方面对我国植物生态学和地植物学作了回顾与展望。一、回顾:1.亚热带和热带森林区的植被研究。2.温带森林区的植被研究。3.温带草原区的植被研究。4.温带荒漠区的植被研究。5.青藏高寒高原区的植被研究。6.中国植被及其地理、分区和植被图研究。7.环境植物学的研究等。二,展望1.植被基本理论的研究2.植被图志的编制和植被制图学研究 3.栽培植物群落和经济植物生态学特性研究4.实验群落学和植物生理生态学研究5.陆地生态系统的结构和功能的研究6.环境保护的植物生态学研究7.植物和植物群落指示性研究  相似文献   

4.
马蹄香大小孢子发生及雌雄配子体形成   总被引:1,自引:0,他引:1  
马蹄香(Sarumahenryi,Oliv.)花药壁的发育属双子叶型。花粉母细胞减数分裂为同时型,四分体主要为四面体形,少数为左右对称式排列。腺质绒毡层,其细胞可排列为不规则的两层,双核或多核。到单细胞花粉阶段,绒毡层细胞内切向壁上出现许多乌氏体。成熟花粉为2细胞型,圆球状,具单萌发沟。雌蕊6心皮,上部彼此分离、下部联合。倒生胚珠,双珠被,厚球心。胚囊发育蓼型。成熟胚囊为七细胞结构,但两个助细胞退化较早。  相似文献   

5.
The ultrathin structure of the amoeboid flagellate Thaumatomonas coloniensis Wylezich et al. has been studied. The cell is surrounded by somatic scales forming on the surface of the mitochondria. The heterodynamic flagella emerge from the small flagellar pocket. Both flagella are covered by pineal scales and thin twisted mastigonemes. The kinetosomes lie parallel to each other. The transitional zone of the flagella carries the thin-walled cylinder. The transversal plate of the flagella is above the cell surface. The flagellar root system consists of three microtubular bands and a fibrillar rhizoplast. The vesicular nucleus and Golgi apparatus are of the usual structure. The mitochondria contain tubular cristae. The extrusive organelles (kinetocysts) contain amorphous material and a capsule; they are located in cytoplasm. The capsule consists of a muff and cylinder. Osmiophilic bodies of various shapes contain crystalloid inclusions. The pseudopodia capturing the bacteria emerge from the ventral groove. The groove is armored by the two longitudinal groups of the close situated microtubules. Microbodies and symbiotic bacteria have not been discovered. The resemblance of Th. coloniensis with other thaumatomonads is discussed.  相似文献   

6.
荔枝的胚胎学研究   总被引:11,自引:1,他引:10  
  相似文献   

7.
鞑靼滨藜(Atriplex tatarica L.)药壁4层细胞,中层1层;绒毡层腺质型。孢原细胞1列或2弄;同花药异花粉囊小孢子母细胞减数分裂为同步,同花粉囊减数分裂大部分同步,部分非同步;四分孢子多为四面体形,少数是左右对称形,胞质分裂同时型;成熟花粉粒为风状饰纹,3-细胞型;单子叶型药壁。弯生胚珠,厚珠心型;双珠被,四分子孢子直线。反足细胞受精前退化,属蓼型胚囊。胚的发育为藜型,胚乳细胞在球  相似文献   

8.
长豇豆的胚珠具内外两层珠被,内珠被在种子发育早期退化消失,种皮仅由外珠被发育而成。外珠被的外表皮细胞径向伸长,外壁和经向壁增厚,形成约占成熟种皮厚度一半的栅栏层;亚表皮细胞发育为骨状石细胞层。第三层细胞类似于亚表皮层但细胞壁增厚不明显,其内方的多层薄壁细胞形成海绵组织。种脐具两层栅栏细胞,外栅栏层及其以外部分由珠柄组织发育而成管胞群。本文还对脐缝和管胞群的作用以及豆科种子的吸水机制进行了讨论。  相似文献   

9.
舞花姜花部维管束系统的解剖学研究   总被引:1,自引:0,他引:1  
关岚岚  邹璞  廖景平 《西北植物学报》2008,28(12):2385-2392
对舞花姜(Globba racemosa)花部维管束系统进行解剖学观察分析,以探讨其缺失雄蕊的去向及其唇瓣和腺体结构的属性.结果显示:(1)舞花姜花梗部的维管束分散排列在基本组织内.(2)子房基部的维管束排成2部分,中央区为分散排列的小维管束,外方为一轮大维管束环,且外环维管束发育为子房壁维管束,心皮背束和隔膜束均起源于中心区维管束,二者的分支在延长部形成一个维管束网结;在网结之上,近轴面的两束心皮背束分支分别进入到2枚侧生退化雄蕊中并成为其主束,远轴面心皮背束的内方分支则成为唇瓣中束,三束心皮背束的其余分支均上行入萼片.(3)唯一1枚功能雄蕊接受近轴面隔膜束的内方主支作为其主束,远轴面2枚隔膜束的主支最后进入唇瓣的两侧束,三束隔膜束的外分支均发育为花瓣束.研究认为:舞花姜的唇瓣是一个三重结构,其中央维管束代表1枚外轮雄蕊,两侧维管束则分别代表2枚内轮雄蕊;舞花姜的2枚花瓣状退化雄蕊与唇瓣的中央一起构成外轮雄蕊,唯一1枚可育雄蕊和唇瓣的两侧同属内轮雄蕊.本研究结果支持姜科子房延长部形成的腺体属于子房上部心皮边缘的维管化附属物的观点.  相似文献   

10.
吉林省满族体质特征调查   总被引:8,自引:2,他引:6  
  相似文献   

11.
严重缺碘对体质及遗传性状影响的研究   总被引:3,自引:2,他引:1  
对严重缺碘地区一个容貌特殊,身材较矮,智力低下的人群进行了体质特征及遗传性状的研究,并与国内有关本地区的调查资料进行了对照,提出人类体质特征和遗传性状除与人种、地理环境异同直接相关外,人体不可缺少的微量元素的摄入水平在一定程度上对其也产生影响。并且认为同一人种、民族居住同一地理位置所产生的体质差异应从水文、地质、生活方式、生活水平的不同进行综合分析。  相似文献   

12.
鳗鲡肝脏、脾脏显微与超微结构   总被引:27,自引:0,他引:27  
郭琼林  卢全章 《动物学报》1994,40(2):125-130
经光镜和电镜观察发现:鳗鲡肝脏的肝小叶不规则。肝细胞胞质内富含多种细胞器及包含物。胆小管由2—4个肝细胞围成,相邻肝细胞间有连接复合体封闭胆小管。肝血窦为有孔型、孔处无隔膜,内有巨噬细胞。窦周隙明显,未见贮脂细胞。肝细胞向胆小管腔与窦周隙面伸出许多指状微绒毛。脾脏内白髓中淋巴细胞聚集成群,未见明显脾小结、淋巴鞘。红髓由脾索与脾窦组成,动脉分支末端(壁厚的毛细血管)可开放于红髓,无明显巨噬细胞中心。脾窦及脾小动脉内皮细胞通常为长杆状、沿血管纵向平行排列。脾窦为有孔型,孔处可见薄的隔膜。脾小动脉内皮外为2—5层平滑肌(多数为纵行)。  相似文献   

13.
铃兰的胚胎学研究   总被引:4,自引:0,他引:4  
铃兰(Convallaria majalisL.)的花药四室,药壁发育为单子叶型。腺质绒毡层发育后期出现双核至多核。小孢子四分体主要呈左右对称型,偶见四面体型。胞质分裂为连续型。二细胞型花粉。子房三室,中轴胎座。胚珠倒生,双珠被,厚珠心。珠孔由内珠被形成。胚囊发育为葱型和英地百合型。受精以后,在子房壁、珠柄和外珠被细胞中含有草酸钙针晶。胚发育类似于石竹型,但基细胞发生纵裂形成两个子细胞。核型胚乳;合点端具巨形胚乳核  相似文献   

14.
长吻鮠精巢及精子结构的研究   总被引:11,自引:0,他引:11  
长吻鮠精巢高度分支呈指状。后1/3紫红色,由上皮细胞组成,既不产生精子,也不贮存精子。精巢的内部结构为叶型,由体细胞和生殖细胞构成,小叶的基本单位是小囊。精子头短而圆,主要为核占据,无顶体,核凹窝十分发达,有中心粒帽;尾极长,具侧鳍,轴丝基部有发达的囊泡状结构和线粒体。  相似文献   

15.
The flower develops in March and blossoms in early May in Nanjing. The cytokinesis of microsporocytes is simultaneous and most tetrads are tetrahedral. The tapetum is secretory and the nuclei become polyploid at last. The style is solid and most ovaries are unilocular, rarely bilocular. The ovule is pendulous, anatropous and unitegmic. The nucellus is pseudocrassinucellate. An obturator formed by transmitting tissue covers the micropyle. The raphe vascular strand extends into the integument when it reaches the chalaza and on a whole keeps a “U” shape. The endothelium cell is uninucleate. In most cases no nucellar cap is formed. No hypostase is found below the embryo sac. The archesporium is one-celled. The embryo sac development conforms to the Polygonum or Allium types. The degeneration of the megaspores in the linear tetrad usually occurs from the chalazal toward the micropylar end. Two synergids persist during fertilization. Three antipodal cells are uninucleate and ephemeral. Two polar nuclei fuse at the time of fertilization. The fertilization type accords with porogamy. The syngamy is premitotic. The development of endosperm is cellular. The initial four successive divisions of the primary endosperm cell are transverse-verticaltransverse-transverse subsequently, giving rise to sixteen cells of the early endosperm. The mature embryo is straight and nearly as long as the endospermous seed. The cotyledons are more or less cordate at base. The seedoat is thin and composed of 5-11 layers of compressed cells. Neither embryo nor endosperm contain the alkaloid camptothecine. The major similarities of Nyssa sinensis to the American nyssas in embryology, which may be a counted as the generic features, are the polyploid tapetum cells, the unitegmic ovule with U-shaped vascular strand, the direct enlargement of the archesporial cell to produce the megasporocyte, the pseudocrassinucellus, the usual absence of the nucellar cap, the Polygonum or Allium type of the embryo sac development, the first degeneration of the metachalazal megaspore, the ephemeral antipodal cells, a single nucleolus in the nucleus ofthe primary endosperm cell, the more or less cordate base of the cotyledons.  相似文献   

16.
应用扫描电镜(SEM)与透射电镜(TEM)观察了黄姑鱼和大黄鱼精子的超微结构。结果显示,黄姑鱼和大黄鱼精子无论在形态、大小还是超微结构上都十分相似。黄姑鱼和大黄鱼精子均由头部、中段和尾部(鞭毛)3部分组成。精子头部形状近似椭圆形,无顶体,细胞核呈肾形。中心粒复合体位于细胞核背侧,近、远端中心粒相互垂直,远端中心粒分化成基体并形成轴丝。中段的袖套呈筒状,4~5个圆形的线粒体围绕轴丝呈环形排列。精子尾部为单鞭毛,轴丝为典型“9+2”结构,鞭毛表面质膜形成不规则侧鳍。  相似文献   

17.
The bronchial ramification in one specimen of gorilla lung was examined from the viewpoint of comparative anatomy, on the basis of the fundamental structure of bronchial ramification in the mammalian lung (Nakakuki, 1975, 1980). The right lung of the gorilla consists of the upper, middle, lower, and accessory lobes. The right lung has the dorsal, lateral, and ventral bronchiole systems, but the medial bronchiole system is lacking. The upper lobe is formed by the first branch of the dorsal bronchiole system. The middle lobe is formed by the first branch of the lateral bronchiole system. The accessory lobe is formed by the first branch of the ventral bronchiole system. The remaining bronchioles constitute the lower lobe. The left lung consists of the middle and lower lobes; the upper and accessory lobes are lacking. The left lung has the dorsal and lateral bronchiole systems, but the ventral and medial bronchiole systems are lacking. The middle lobe is formed by the first branch of the lateral bronchiole system. The remaining bronchioles constitute the lower lobe. The bronchial ramifications of the gorilla lung are rather similar to those of the human lung.  相似文献   

18.
The trabeculae cranii are at first quite separate from each other, after few days their anterior two fifths are connected by a trabecular plate which is obliterated throughout development. The paired origin of the parachordal plate is not observed. The fused posterior orbital cartilages chondrify in the form of a wide short plate, traversed by the oculomotor and trochlear nerves. The basicranial fenestra and fenestra ovalis are formed by the degeneration of pre-existing cartilage. The cochlear portion is completely fused with the parachordal plate from the very beginning. The elements of the pterygoquadrate are fused together. The quadrate and Meckel's cartilage are in close contact from the very beginning. While the lower part of the interorbital septum is derived from the trabecula communis, its upper part is derived from the anterior orbital cartilages. The lateral parts of the fused posterior orbital cartilages give rise to most of the taeniae and pilae of the orbitotemporal region. There is only one commissure between the auditory capsule and parachordal plate. A cartilaginous connection between the distal portion of the columella auris and ceratohyal persists for some time. The parietotectal and paranasal cartilages are fused together from the very beginning. The processus paroticus originates from the columella auris. In the fully formed stage the notochord is completely embedded in the occipital condyle. The union between the condyle and odontoid process persists. The auditory capsules and occipital arches contribute to the formation of the tectum synoticum plus posterius. The prefacial commissure and facial foramen lie in front of the cochlear portion. The columella auris possesses a processus internus (connected with the quadrate), but the processes a dorsalis has completely disappeared. The orbitotemporal region is quite complete. A medial fenestra is formed in the planum supraseptale. A fenestra is observed in each of the interorbital and nasal septa. The lamina transversalis anterior is fused with the parietotectal cartilage. A complete zona annularis is present. The outer wall of the paranasal cartilage is perforated by a large fenestra lateralis. The parietotectal and paranasal cartilages and the posterior process of the lamina transversalis anterior contribute to the formation of the concha nasalis. There is a contact between the planum antorbitale and nasal septum. The pterygoid process has disappeared. The common characters of the lacertid chondrocranuium are deduced.  相似文献   

19.
C3、C4和CAM途径的生态学意义   总被引:3,自引:1,他引:2  
罗耀华 《生态学报》1985,5(1):15-27
本文通过C_3,C_4和CAM植物在不同环境中的分布,从3个方面阐述了这3种碳同化途径在利用环境资源时的生态学意义——资源分隔: 1.光合途径的空间分异:(1)不同光合类型植物的气候带(水平和垂直带)和地理区域分布;(2)不同光合类型植物在微环境中的分布。 2.光合途径的时间分异。 3.光合途径在资源分隔中的重叠。  相似文献   

20.
沉香叶解剖结构的研究   总被引:6,自引:2,他引:4  
唐为萍  陈树思 《广西植物》2005,25(3):229-232,i005
通过石蜡切片法,光学显微镜观察,研究了沉香叶的解剖结构。结果表明,沉香叶为典型的异面叶,但具有许多旱生特征。表皮由一层排列紧密的形状不规则的表皮细胞组成,细胞外壁角质膜较厚,上表皮角质膜较下表皮的厚3.48μm,下表皮上零星分布着单细胞表皮毛,气孔类型为无规则型,仅分布在下表皮上,微下陷;叶肉组织发达,其间分布着较多的长方晶体,其长轴与表皮垂直;栅栏组织由1~2层圆柱形细胞组成,其外层细胞转化为异细胞,栅栏组织∶海面组织为1∶3.5,下表皮内具有1~2层由异细胞组成的下皮层;主脉发达,有异细胞组成的维管束鞘,具内生韧皮部;叶内具有发达的木质部外纤维。以上特征反映出植物结构与环境的统一性。  相似文献   

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