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1.
用五叶风藤 (HolboelliafargesiiReaub)茎尖染色体制片 ,研究其染色体组型 ,结果表明 :五叶风藤的染色体组型公式为 2n =2x =16 =12m 4sm ,染色体基数x =8,第 4号染色体上有一对染色体随体 ,核型为 2B类型 ,其中 2n =4x =32 =2 4m 8sm的四倍性细胞相当普遍。  相似文献   

2.
大血藤科花粉形态及外壁超微结构的研究   总被引:6,自引:0,他引:6  
对大血藤科及木通科的八月瓜属HolboelliaWall.和木通属AkebiaDecne花粉进行了光镜及电子显微镜的观察研究。研究结果表明,其花粉形态具有较为明显的相似性,如花粉均为3沟,外壁表面具穴状纹饰,甚至大小也很近似。但从其外壁结构看,大血藤花粉的外壁内层为结均一的致密层组成  相似文献   

3.
Testa SEM characters of Lardizabalaceae and Sargentodoxaceae have not been used in former studies of taxonomy and phylogeny. In this work examined by scanning electron microscope (SEM). was the testa surface of 5 genera including 15 species of Lardizabalaceae and Sargentodoxaceae. Sargentodoxaceae is found quite different from Lardizabalaceae in its smooth test. The testa sculpture of Akebia, Holboellia and Stauntonia is basically striate, but that of Sinofranchetia, though striate, is verrucous on striations. Decaisnea is very isolated for its mosaic testa sculpture. The tesa examination confirms the rationality of the taxonomic treatment of Sargentodoxaceae by Stapf, the isolated taxonomic position of Decaisnea and Sinofranchetia in Lardizabalaceae, and the close interrelationship among Akebia, Holboellia, and Stauntonia.  相似文献   

4.
Stauntonia angustifolia (Wall.) Wall. ex Christenh., formerly Holboellia angustifolia Wall. is described and illustrated. Its recent history in cultivation in Cambridge is discussed.  相似文献   

5.
基于广义形态学性状对木通科的分支系统学分析   总被引:3,自引:1,他引:2  
基于43个广义的形态学性状,对木通科进行了分支系统学分析。经过简约性分析,得到了68个同等简约的分支树。50%多数规则一致树的分支结构与以前建立的族划分系统基本一致。外类群大血藤属与木通科的勃奎拉藤属形成姐妹群,与以前的分支分析结果一致,但在分子系统发育树中,大血藤属却是整个木通科的姐妹群;除此之外,形态分支树的结构与分子树的结构差别不大,但一致性指数、保持性指数和各分支内部支持率均较低。单型的猫儿屎族和串果藤族位于分支树的基部,拉氏藤族与木通族是姐妹群,在木通族内,长萼木通属和木通属是姐妹群,作为一个分支;另一分支是PHS(牛藤果属、八月瓜属和野木瓜属)复合群,牛藤果属位于八月瓜属和野木瓜属各类群的基部。但八月瓜属和野木瓜属的属内系统发育关系仍有待进一步研究。  相似文献   

6.
木通科、大血藤科花粉壁的超微结构研究   总被引:3,自引:0,他引:3  
夏泉  孔杰 《植物研究》1991,11(4):93-98
应用透射电子显微镜(TEM)观察了木通科Decaisnea,Sinofr-anchetia,Holboellia,Stauntonia属以及大血藤科Sargentodoxa属共18种植物花粉壁的超微结构。所观察的木通科和大血藤科植物具较发达的覆盖层和柱状层;外壁内层以及内壁均在萌发沟处明显增厚;基层通常不甚发达。与扫描特征相对应的覆盖层结构特征,显示出类群的特异性。在Stauntonia属,覆盖层富于形态变化,反映出该属在木通科中较进化的地位;大血藤(Sarg-entodoxa cuneata)花粉壁结构隶属木通型花粉结构,表明大血藤科与木通科的密切关系。  相似文献   

7.
报道了黄山地区18种木本植物的染色体数,分属于15个科中的18个属,其中14种和2个属为首次报道;同时对Aphananthe,Fortunearia,Loropetalum,Holboellia,Platycarya属的染色体数及其在分类上的意义作了简单讨论。  相似文献   

8.
基于叶绿体trnL_F序列单独分析以及trnL_F和rbcL序列联合分析重建了木通科的分子系统发育。本研究的系统发育拓扑结构与覃海宁和塔赫他间的族划分系统非常一致。猫儿屎族和串果藤族在系统发育树上位于本科的基部。由分布于南美的勃奎拉藤属和拉氏藤属组成的拉氏藤族得到了trnL_F序列分析 (10 0 % )和联合序列分析 (99% )的很好支持。木通族在两个分析里都得到了 10 0 %的靴带支持率。新建立的长萼木通属在trnL_F树上嵌套在木通属内 ;然而 ,在联合分析的树上 ,它与木通属形成姐妹群并得到很高的支持率。在系统发育上关系密切的 3个属 :牛藤果属、八月瓜属和野木瓜属之间的关系仍未解决。牛藤果与八月瓜在两个分析里都形成姐妹群 ,但支持率低。小花鹰爪枫嵌套在野木瓜属内 ,并与西南野木瓜形成姐妹群。木通族内这 3个属可能都不是单系 ,它们的属间界限和属的界定需要更多的分子和形态数据的进一步研究。  相似文献   

9.
Six new species of the genus Zingiber from Borneo are presented. Z viridiflavum was collected in primary lowland forest, while Z chlorobracteatum was collected in hilly secondary forest. Both are characterized by their slender fusiform inflorescences with yellow-green bracts. Z. flagelliforme found in primary lowland forest displays a peculiar reproduction habit in its tapering leafy shoots which bend over to trail on the ground where plantlets produced in the leaf-axis take root. Z velutinum was found in mid-elevation secondary forest. It is a tall plant with large ovate inflorescences and bright red, densely hairy bracts. Z phillippsii was found in a gulley in montane primary forest. It is vegetatively characterized by its purple stems and glabrous leaves while the inflorescence has a similarity to the common Bornean species Z. coloratum. Z. georgeii is distinct by its procumbent inflorescences with orange bracts. Z viridiflavum, Z. chlorobracteatum, Z. flagelliforme, Z. phillippsii and Z velutinum are from Sabah and Z georgeii is from Sarawak.  相似文献   

10.
A. Y. Sun  E. J. Lambie 《Genetics》1997,147(3):1077-1089
The gonad of the Caenorhabditis elegans hermaphrodite is generated by the postembryonic divisions of two somatic precursors, Z1 and Z4, and two germline precursors, Z2 and Z3. These cells begin division midway through the first larval stage. By the end of the fourth larval stage, Z1 and Z4 produce 143 descendants, while Z2 and Z3 give rise to ~1000 descendants. The divisions of Z2 and Z3 are dependent on signals produced by Z1 and Z4, but not vice versa. We have characterized the properties of five loss-of-function alleles of a newly described gene, which we call gon-2. In gon-2 mutants, gonadogenesis is severely impaired; in some animals, none of the gonad progenitors undergo any postembryonic divisions. Mutations in gon-2 have a partial maternal effect: either maternal or zygotic expression is sufficient to prevent the severe gonadogenesis defects. By cell lineage analysis, we found that the primary defect in gon-2 mutants is a delay (sometimes a complete block) in the onset and continuation of gonadal divisions. The results of upshift experiments using a temperature-sensitive allele suggest that zygotic expression of gon-2 begins early in embryogenesis, before the birth of Z1 and Z4. The results of downshift experiments suggest that Z1 and Z4 can generate the full complement of gonadal tissues even when gon-2 function is inhibited until the end of the second larval stage. Thus, gon-2 activity is probably not required for the specification of gonadal cell fates, but appears to be generally required for gonadal cell divisions.  相似文献   

11.
The winter moth (Operophtera brumata L., Lepidoptera: Geometridae) utilizes a single hydrocarbon, 1,Z3,Z6,Z9-nonadecatetraene, as its sex pheromone. We tested the hypothesis that a fatty acid precursor, Z11,Z14,Z17,19-nonadecanoic acid, is biosynthesized from ??-linolenic acid, through chain elongation by one 2-carbon unit, and subsequent methyl-terminus desaturation. Our results show that labeled ??-linolenic acid is indeed incorporated into the pheromone component in vivo. A fatty-acyl-CoA desaturase gene that we found to be expressed in the abdominal epidermal tissue, the presumed site of biosynthesis for type II pheromones, was characterized and expressed heterologously in a yeast system. The transgenic yeast expressing this insect derived gene could convert Z11,Z14,Z17-eicosatrienoic acid into Z11,Z14,Z17,19-eicosatetraenoic acid. These results provide evidence that a terminal desaturation step is involved in the winter moth pheromone biosynthesis, prior to the decarboxylation.  相似文献   

12.
13.
Recent collections from Sabah and Sarawak have revealed a wide species diversity among the Bornean members of the genus Zingiber. Four previously unknown and one incompletely known species of the genus are presented. Z. vinosum is a lowland species characterized by its burgundy colour of the lower surface of the leaves. Z. lambii was collected in primary lowland forest on ultramafic soil while Z. argenteum was collected in primary lowland forest on limestone. Both are characterized by their silvery leaves and orange inflorescences. Z. pendulum, found in primary mountain forest, has pending leafy stems and a deeply split labellum with very well developed side-lobes. Z. latifolium, found in secondary mountain forest, is vegetatively distinct by its broad leaves with a densely pubescent margin Z. vinosum, Z. Iambii, Z. pendulum and Z. latifolium are from Sabah and Z. argenteum is from Sarawak.  相似文献   

14.
New geometric isomers, methyl (9Z,11Z)-13-hydroperoxy-9,11-octadecadienoate and methyl (10Z,12Z)-9-hydroperoxy-10,12-octadecadienoate, were proved to be present in methyl linoleate hydroperoxide produced by autoxidation. They were identified from their UV, MS, and 1H-NMR spectra after conversion to the corresponding oxo derivatives: methyl (9Z,11Z)-13-oxo-9,11-octadecadienoate and methyl (10Z,12Z)-9-oxo-10,12-octadecadienoate. Their chromatographic behavior is described.  相似文献   

15.
In a previous study we have reported that both (E,Z)-8,10-dodecadienol (E,Z) and (Z,Z)-8,10-dodecadienol (Z,Z) isomers inhibit the attraction of male codling moth, Cydia pomonella L. when added to (E,E)-8,10-dodecadienol (E,E) while the (Z,E)-8,10-dodecadienol (Z,E) isomer induces slight increase in the number of males attracted to the pheromone source. In the present study, we have tested the behavioral activity of the individual geometrical isomers E,Z; Z,E and Z,Z. A few number of codling moth males flew to the Z,E-isomer while the other two isomers (i.e. E,Z and Z,Z) did not elicit any upwind orientation. Analysis of the flight behavior to the E,E- and Z,E-isomer showed significant differences in most of the flight parameters evaluated. Based on the biological observations and molecular modeling, we suggest that the behavioral activity of the Z,E-isomer is due to presence of specific receptors for this isomer on male antennae and not to its structural resemblance to the E,E-isomer. These results underline the importance of the Z,E-isomer in sex attraction of male codling moth.  相似文献   

16.
THE ULTRASTRUCTURE OF THE Z DISC IN SKELETAL MUSCLE   总被引:30,自引:30,他引:0       下载免费PDF全文
This electron microscopic study deals with the structure of the Z disc of frog's skeletal muscle, with special regard to the I filaments—whether they pass through the Z disc or terminate at it. In most longitudinal sections the I filaments terminate as rod-like projections on either side of the Z disc, one I filament on one side lying between two I filaments on the opposite side. This indicates that the I filaments are not continuous through the Z disc. The rod-like projections are often seen to consist of filaments (denoted as Z filaments) which meet at an angle. In cross-sections through the Z region the I filaments and Z filaments form tetragonal patterns. The I filaments are situated in the corners of the squares; the oblique Z filaments form the sides of squares. The tetragonal pattern formed by the Z filaments is rotated 45 degrees with respect to the tetragons formed by the I filaments on both sides of Z. This structural arrangement is interpreted to indicate that each I filament on one side of the Z disc faces the center of the space between four I filaments on the opposite side of Z and that the interconnection is formed by four Z filaments.  相似文献   

17.
山东莱芜地区晚寒武世炒米店组牙形石生物地层学研究   总被引:1,自引:0,他引:1  
本文报道了山东莱芜地区黄羊山剖面炒米店组的牙形石生物地层学研究成果。在该剖面上寒武统的炒米店组建立了9个牙形石带,自上而下分别是Cordylodusangulatus带,C.lindstromi带,C.intermedius带,C.proavus带,Eoconodontusnotchpeakensis带,Proconodontusmuelleri带,P.posterocostatus带,P.tenuiserratus带和Prooneotodusrotundatus-Muelleroduserectus带。牙形石动物群的面貌显示该地区炒米店组顶部在时代上已属早奥陶世,表明该地区的寒武-奥陶界线与三山子组白云岩的底界并不一致,后者在层位上稍高。建立并描述了一副牙形石新种Westergaardodinahuangyangshanensissp.nov.。  相似文献   

18.
Analysis of sex pheromone glands of the apple leafroller Bonagota cranaodes Meyrick by gas chromatography coupled with mass spectrometry or electroantennographic detection showed the presence of 14 structurally related acetates and alcohols of the chain length 10-18, including the main pheromone component (E,Z)-3,5-dodecadienyl acetate (E3,Z5-12Ac). Male antennae responded to the main compound, its Z,Z isomer, (E,Z) -3,5-tetradecadienyl acetate (E3,Z5-14Ac), and the monoenes (Z)-5-dodecenyl acetate (Z5-12Ac) and (Z)-9-hexadecenyl acetate (Z9-16Ac). Traps baited with a four-component blend of E3,Z5-12Ac, Z5-12Ac, E3,Z5-14Ac, and Z9-16Ac in a 100:5:5:100 ratio were significantly more attractive than the main compound alone. This improved trap lure is more suitable for monitoring population densities of B. cranaodes, and for detection of the onset of the seasonal flight period. A more complete pheromone blend is of importance also with respect to current attempts to develop mating disruption for control of this major pest of apple in Brazil.  相似文献   

19.
In skeletal muscle Z bands, the ends of the thin contractile filaments interdigitate in a tetragonal array of axial filaments held together by periodically cross-connecting Z filaments. Changes in these two sets of filaments are responsible for two distinct structural states observed in cross section, the small-square and basketweave forms. We have examined Z bands and A bands in relaxed, tetanized, stretched, and stretched and tetanized rat soleus muscles by electron microscopy and optical diffraction. In relaxed muscle, the A-band spacing decreases with increasing load and sarcomere length, but the Z lattice remains in the small-square form and the Z spacing changes only slightly. In tetanized muscle at sarcomere lengths up to 2.7 micron, the Z lattice assumes the basketweave form and the Z spacing is increased. The increased Z spacing is not the result of sarcomere shortening. Further, passive tension is not sufficient to cause this change in the Z lattice; active tension is necessary.  相似文献   

20.
涉及近年来采集自青岛沿海的自由生聚缩虫属纤毛虫14种,包括9个国内新纪录:交替聚缩虫Zoothamnium alternans Claparède & Lachmann,1859,弗氏聚缩虫Z. foissneri Ji et al.,2005,黑凯聚缩虫 Z. hiketes Precht,1935,海洋聚缩虫 Z. marinum Mereschkowski, 1879,霉聚缩虫Z. mocedo Entz,1884,倪氏聚缩虫 Z. nii Ji et al.,2005,拟树状聚缩虫 Z. pararbuscula Ji et al., 2005,王氏聚缩虫Z.wangi Ji et al., 2005,许氏聚缩虫 Z. xuianum Sun et al.,2005;以及其他5个已知种:群栖聚缩虫Z. commune Kahl, 1933,双缘聚缩虫Z. duplicatum Kahl,1933,巨大聚缩虫Z.maximum Song,1986,羽状聚缩虫Z.plumula Kahl,1933,中国聚缩虫Z.sinense Song,1991.对以上各种作了简要的综合性描述,并给出了种检索表.  相似文献   

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