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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.
新疆察布查尔锡伯族体质特征调查   总被引:44,自引:9,他引:35  
本文调查了新疆察布查尔锡伯族居民220人(男130人、女90人),年龄从20岁到78岁。观察22项,测量65项。调查结果表明,锡伯族居民具有典型的黄种人东亚人种的特征。如头圆宽且高,胡须少,眼裂狭窄、上眼睑褶皱多达睫毛处。耳大、鼻梁较直、鼻高中等,指距长、骨盆宽等。这些特征用等差级数法比较,与达斡尔族、华北地区汉族、蒙古族较接近,与苗族、黎族较远。  相似文献   

3.
掌裂橐吾的胚胎学   总被引:2,自引:0,他引:2  
首次报道了掌裂橐吾的胚胎发育过程。药壁发育双子叶型;绒毡层发育属、The Cosmos bipinnatus”型,成熟花粉为3细胞型;单珠被,薄珠心,倒生胚珠;具发达的珠被绒毡层;胚囊发育为4孢子型,类似德鲁撒型(Drusa);胚乳发育为核型,胚胎发育为紫菀型千里光变型。  相似文献   

4.
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   

5.
湖南土家族的体质特征   总被引:20,自引:8,他引:12  
以20至69岁的湖南土家族人为观察测量对象,根据1392人(男896,女496)的身高,1038人(男668,女370)的头部测量,364人(男235,女129)的五官测量和观察结果,分析该民族的体质特征,并与国内其他民族相比较。  相似文献   

6.
款冬的胚胎学   总被引:4,自引:0,他引:4  
刘建全 《西北植物学报》2001,21(3):T001-T003
系统报道了中藏药款冬大小孢子的发生、雌雄配子体发育和胚胎的发育过程,药壁发育双子中型,绒毡层发育接近菊科中的“The Comos bipinnatus”型;成熟花粉为3细胞型;单株被,薄珠心,倒生胚珠,具发达的珠被绒毡层;胚囊发育4孢子型,接近五福花(Adoxa)型胚囊,受精作用属于有丝分裂前配子体融合类型,胚乳发育为核型,胚胎发育紫菀型千里光变型。讨论了该种胚胎学特征的生态学及系统学意义。  相似文献   

7.
维吾尔族的体质特征研究   总被引:37,自引:12,他引:25  
艾琼华  肖辉 《人类学学报》1993,12(4):357-365
1991年5月,对新疆伊梨维吾尔族529人(男271,女258)进行了活体观察和测量。观察29项,测量92项。维吾尔族的主要特征是:黑直发,黑褐色眼,眉毛较浓密,大都有上眼脸皱褶,鼻根中等偏高,大多为直形鼻,鼻尖向前,鼻基部下垂,大多有达尔文结节,耳垢湿型。头面部指数分型,属于特短头型,阔头型和高头型。身材中等偏高,平均身高男168.6毫米,女1578.8毫米。  相似文献   

8.
酸性硫酸盐土中硫的形态含量分布和酸化特征   总被引:5,自引:2,他引:3  
对广东省台山市南部滨海平原酸性硫酸盐土(以下简称ASS)S的形态、含量、分布和酸化特征的研究表明,ASS全硫含量高达0.615%,比咸田高2~6倍,比砂泥田高3~9倍;其硫以无机硫为主,占全硫的82.3%~90.4%,其中,黄铁矿硫的含量最高,占全硫的30.3%~46.2%,黄铁矿硫在剖面中的分布与全硫含量同步。ASS硫含量的空间变异和剖面内部的分异十分显着。ASS发育过程中,适合黄铁矿累积的环境及其持续时间与地形地貌(山)的关系十分密切。ASS的主要致酸物质是黄铁矿的氧化,酸化的ASS的pH一般在5.5以下,最低达2.83.ASS可氧化总酸度一般比实际总酸度高2~3倍,潜在的环境风险极.  相似文献   

9.
大黄鱼精子的超微结构   总被引:43,自引:1,他引:43  
尤永隆  林丹军 《动物学报》1997,43(2):119-126
大黄鱼的精子由头产和尾部两部分组成。头部结构较为独特,其腹侧有一较大的细胞核,背部有中心粒复合体。头部的后端是袖套。细胞核的腹面稍向外突出背面则稍向内凹。细胞核中的染以质浓缩成致密的团块状。团块状的染色质之间分布着松散的纤维状染色质。植入窝位于细胞核的背部表面,由细胞核背面向内凹陷而成,呈一沟状,其走向与精子的长轴平行。  相似文献   

10.
A simple model is presented for the estimation of image blurring in X-ray microscopy of biological specimens in a hydrated environment. The model is essentially based on thermal diffusion of an object to be imaged. The degree of image blurring by diffusion depends on the following situations of the object. The object is free from, is tightly fixed to, or is partially connected to the surrounding structures. The proper imaging time required to achieve a given resolution in X-ray microscopy of biological structures was estimated with the present method. The results suggest that imaging time shorter than 3 msec (free) to 1.4 sec (tightly fixed) is required for the observation of a cell (30 microns in diameter) at the resolution of 100 nm. The model is also applicable to a fragmented object caused by imaging X-rays.  相似文献   

11.
The present paper reports the chromosome numbers and karyotypes of five species in Polygonatum from Anhui of China. The materials used in this work are listed in Table 1, Photomicrographs of somatic metaphase and karyograms of the five species of Polygonatum in Plate 1, 2, 3, the idiograms in Fig. 1-11 and a comparison of the karyotype of them is provided in Table 2. The results are shown as follows: 1. Polygonatum odoratum (Mill.)Druce Two materials were examined. One from Mt. Huangshan, Anhui, has 2n= 16 = 10m (3sc)+ 6sm (Plate 1 :A, B). The idiogram is shown in Fig. 1. The chromosomes range in length from 2.85 to 8.85 μm, with the total length 48.63μm and the ratio of the longest to the shortest 3.11, The karyotype belong to Stebbins’(1971) 2B. The two chromosomes of the first pair have arm ratios 1.01 and 1.29 respectively, and The first pair has one chromosome carrying a satellite attached to the short arm, showing heterozyosity .The chromosome num ber of 2n= 16 in P. odoratum and its karyotype are reported for the first time. The other from Langyashan, Chu - xian, Anhui, is found to have 2n = 18 = 10m (Isc)+2sm+6st(2sc) (Plate 1: C, D). The idiogram is shown in Fig. 2. The chromosomes range in length from 2.43 to 8.29μm, with the total length 46.67µm and the ratio of the longest to the shortest 3.41. The karyotype is also of 2B. In a somatic chromosome complement the 2nd pair have one chromosome carrying a satellite attached to the long arm, showing heterozygosity. 2. Polygonatum filipes Merr. Two materials were examined. One from the Huangshan, Anhui is found to have two cytotypes: 2n= 16 and 2n=22. This paper reports one of them. The karyotype formula is 2n=22=8m+8sm(2sc)+6st(Plate 3: Q, R). The idiogram is shown in Fig. 3. The chromosomes range in length from 2.55- 5.85μm, with the total length 45.01 μm and the ratio of the longest to the shortest 2.29. The karyotype belongs to 3B. The other material from the Fangchang, Anhui, is shown to have four cytitypes: 2n= 14, 2n= 16, 2n=20 (Plate 3: W) and 2n=22. This paper reports two of them. Type I: the karytype formula is 2n=14=10m+4sm (Plate 3: S, T). The idiogram is shown in Fig. 5. The chromosomes range in length from 2.59 to 7.61μm, the total length 37.44μm and the ratio of the longest to the shortest is 2.94. the karyotype belongs to 2B. Type II :The karyotype formula is 2n=16=8m+4sm+4st (Plate 3: U, V). The idiogram is shown in Fig. 4. The chromosomes range in length from 2.65 to 8.21 μm, the total length 46.01 μm and the ratio of the longest to the shortest 3.10. The karyotype belongs to 2B. The chromosome numbers of 2n=20, 2n= 14 and 2n=22, and karyotype of 2n= 14 and 2n=22 in P. filipes are reported for the first time. 3. Polygonatum cytonema Hua Two materials were examined. One from the Langyashan, Chuxian, anhui, is found to have 2n = 18 = 8m (2sc)+ 6sm+ 4st (Plate 2: K, L). The idiogram is shown in Fig. 7. The chromosomes range in length from 3.41 to 9.21 μm, the total length 56.34μm and the ratio of the longest to the shortest is 2.70. The karyotype belongs to 2B. The other material from the Huangshan, Anhui, has two cytotypes: 2n=20 and 2n= 22. Type I: The karyotype formula is 2n= 20= 8m+ 6sm+ 6st (Plate 2: M, N). The idiogram is shown in Fig. 8. The chromosomes range in length from 1.75 to 5.03μm, with the total length 32. 91μm and the ratio of the longest to the shortest 2. 87. The karyotype is also of 2B. Type II: The karyotype formula is 2n=22=6m+ 8sm+4st+ 4t (Plate 2: O, P ). The idiogram is Shown in Fig. 10. The chromosomes range in length from 1.75 to 4.95 μm, with total length 35.05μm and the ratio of the longest to the shortest 2.83. The karyotype brlongs to 3B. 4. Polygonatum desoulayi kom. The material from Xuancheng, Anhui, is found to have karyotype 2n = 22 = 10m (2sc) + 6sm (lsc) + 6st ( Plate 2. I, J). The idiogram is shown in Fig. 6. The chromosomes range in length from 1.86 to 5.61μm, with the total length 41.98μm and the ratio of the longest to the shortest 3.02. The karyotype is also of 3B. The first pair has one chromosome carrying a satellite attached to the long arm, showing heterozygosity. The chromosome number and karyotype of Chinese material are reported for the first time. 5. Polygonatum verticillatum (L.) All. The material from the Langyashan, Chuxian, Anhui is found to have two cytotypes. Type 1: the karyotype formula is 2n = 18 = 2m+ 2sm+ 10st+ 2t+ 2T (Plate 1: G, H). The idiogram is shown in Fig.9. The chromosomes range in length from 1.86 to 4.03μm, with total length 28.28μm and the ratio of the longest to the shortest 2.17. The karyotype classification belongs to 3B. Type II: The karyotype formula is 2n=24=6m+4sm+12st+2T (Plate 1: E, F). The idiogram is shown in Fig. II. The chromosomes range in length from 2.01 to 5.03μm, with total length 41.36μm and the ratio of longest to shortest 2.50. The karyotype is also of 3B. The chromosome numbers and karyotypes of Chinese material are reported for the first time.  相似文献   

12.
四种植物花蜜腺的解剖学研究   总被引:1,自引:0,他引:1  
通过对石竹、庐山小檗、活血丹和紫云英四种植物花蜜腺的外部形态、显微切片和扫描电镜观察,了解到石竹花蜜腺是雄蕊类型,蜜汁通过角质层间小孔分泌;庐山小檗花蜜腺是花被类型,其每个分泌表皮细胞的外切向壁中央向内凹陷与角质层之间形成角质层下空隙,蜜汁由表皮细胞分泌后贮存于角质层下空隙中,在蜜汁积累过程中不断增加对角质层的压力,最后冲破角质层分泌到体外;活血丹和紫云英花蜜腺属于花托类型,前者蜜汁从分泌表皮细胞通过角质层直接渗出,后者蜜汁通过变态气孔分泌。本试验的四种植物花蜜腺中维管组织有三种不同类型。  相似文献   

13.
The ultrastructure of the microfilaria of Brugia, Nematoda: Filarioidea   总被引:2,自引:0,他引:2  
The microfilaria of Brugia pahangi is a differentiated nematode larva. The basic nematode body plan is present showing cuticle, hypodermis, dorsal, ventral, and lateral cords, muscle cells, longitudinal nerves, papillary nerves, amphids and phasmids. Secretory granules are present in ganglionic cells and in axons in the nerve ring. There is no differentiated pseudocoelom. There is only a single row of muscle cells between each pair of cords. The excretory cell complex is similar in structure to the hypodermal gland cells of other nematodes. The alimentary canal of the microfilaria is very much modified. The pharyngeal cells are attached to the pharyngeal thread which is circular in cross section and there is no pharyngeal musculature. The intestine is represented by the solid mass of the inner body within paired intestinal cells. The intestine is separated from the rectum. The three rectal cells form a syncytium of villi in the anal vesicle. The structure in Brugia is related to the ultrastructure of other microfilariae and it is concluded that the evolution of the modifications of the basic larval structure is due to the small size of these nematodes as a consequence of their adaptation to a parasitic mode of life in the capillaries of the vertebrate host with transmission through an intermediate arthropod vector.  相似文献   

14.
The anatomical basis for the application of neurovascular pedicled muscle transfers of the digastric and stylohyoid muscles in the treatment of velopharynx incompetence is described. The fact that the neurovascular pedicle is located in the cranial third of the muscle bellies provides the safety of the operative procedure. The muscles have to be dissected with respect to that. The direction in which the transferred muscles pull is described. The muscle transposition is combined with the classic Wardill-Kilner operation to lengthen the soft palate. The transferred muscles have to avoid scar contraction and shortening of the soft palate and to gain a muscular function of the soft palate. The clinical use is justified in rare cases as demonstrated in one case.  相似文献   

15.
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   

16.
A study of the embryology of Plagiopteron suaveolens Griffith is presented in order to evaluate the affinities of the genus. Anther wall formation is of the dicotyledonous type. The anther tapetum is glandular and its cells become two to four nucleate. Cytokinesis in the microspore mother cell is simultaneous and the resultant tetrad is tetrahedral. The mature pollen grains are two-celled. The anther has 4-locules at anthesis. The ovule is anatropous, bitegmic and weakly crassinucellate with only one cell-layered parietal tissue. The micropyle is zig-zag in section and formed by both inner and outer integuments which are three and three to four cell layers thick respectively. The megaspore archesporium is one-celled and the embryo sac development is of the Polygonum type. An endothelium is formed with early disintegration of nucellar tissue. The antipodals multiply to 15 to 20 cells. Embryological evidence supports the placement of Plagiopteron in its own family, Plagiopteraceae, with closest relationship with Celastraceae and close relationship with Elaeocarpaceae, Rhizophoraceae and some families of the Geraniales.  相似文献   

17.
D-serine transport system in Escherichia coli K-12   总被引:8,自引:7,他引:1       下载免费PDF全文
The d-serine transport system in Escherichia coli K-12 was studied by use of a mutant unable to form d-serine deaminase, yet resistant to d-serine. The mutant is greatly impaired in its ability to accumulate d-serine, d-alanine, and glycine. Transport of l-alanine is partially affected but transport of l-serine is unaffected. The mutant is also resistant to d-cycloserine, indicating that d-serine is transported by the system responsible for uptake of d-cycloserine. The d-serine transport system is not inducible, but appears to be formed constitutively, as are the transport systems of most amino acids. The transport mutation appears to be multistep and maps to the right of malB on the E. coli linkage map.  相似文献   

18.
1. The selectivities of the ion channels underlying the action potential and the hyperpolarizing response to acetylcholine of the GH cell of Onchidium have been analysed. 2. The rising phase of the action potential is due to an increase in the permeability of the membrane to both Na+ and Ca2+. The Na+ channel is permeable to Li+ and is somewhat permeable to formamidinium, guanidinium and ammonium ions. The Ca2+ channel is permeable to Sr2+ and Ba2+, but not to Mn2+ and Mg2+. 3. The Cl- channel operated by ACh is permeable to chlorate, but not to formate and propionate ions. 4. The selectivities of these channels are similar to those of a number of other channels in other organisms.  相似文献   

19.
An object extraction problem based on the Gibbs Random Field model is discussed. The Maximum a'posteriori probability (MAP) estimate of a scene based on a noise-corrupted realization is found to be computationally exponential in nature. A neural network, which is a modified version of that of Hopfield, is suggested for solving the problem. A single neuron is assigned to every pixel. Each neuron is supposed to be connected only to all of its nearest neighbours. The energy function of the network is designed in such a way that its minimum value corresponds to the MAP estimate of the scene. The dynamics of the network are described. A possible hardware realization of a neuron is also suggested. The technique is implemented on a set of noisy images and found to be highly robust and immune to noise.  相似文献   

20.
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