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1.
百花山植物群落物种多样性研究   总被引:7,自引:0,他引:7  
基于百花山50个样方的调查资料,从不同类型群落的物种多样性及其与海拔的关系等方面对百花山植被进行了分析,并且用DCA排序和海拔高程排序对物种多样性在环境梯度上的分布格局进行了初步研究。结果表明:群落内不同生长型的物种丰富度指数在森林群落中大小顺序为草本层>灌木层>乔木层,灌丛群落主要表现为草本层﹥灌木层,只有荆条灌丛表现为灌木层>草本层;Shannon-Wiener指数在山杨—华北落叶松群落中表现为灌木层>草本层>乔木层,其他森林群落为草本层>灌木层>乔木层,在灌丛群落中主要表现为草本层>灌木层,只有荆条灌丛表现为灌木层>草本层;均匀度指数在灌丛群落中表现为灌木层>草本层,在辽东栎林和山杨—华北落叶松林中表现为灌木层>乔木层>草本层,而其他森林群落表现为乔木层>灌木层>草本层。物种多样性在DCA第一轴排序和海拔高程梯度上都表现出单峰曲线变化趋势,但拟和效果的显著程度不同:丰富度和均匀度指数在海拔高程上曲线的拟和效果优于DCA环境梯度排序效果;而多样性指数则相反。  相似文献   

2.
The wrinkle layer the inner prismatic layer are described in three Triassic ceratid genera: Phyllocludiscites. Megaphyllites Proarcestes. Both layers have their counterparts in the shell wall of the recent Nautilus: the wrinkle layer corresponds to the mantle-adhesive layer the inner prismatic layer to the myostracal layer in Nautilus. A detailed structural functional comparison between these layers is given. The wrinkle layer is also compared with the oblique prismatic layer in recent gastropods.  相似文献   

3.
对水生萤火虫——条背萤Luciola substriata(Gorham)成虫和幼虫发光器的超微结构进行研究。结果表明,成虫发光器由明显的2层组成:反射层和发光层。反射层由排列紧密的“尿酸囊泡”构成,具有发达的气管结构,对光起反射作用;发光层由大量发光细胞构成,内含典型的发光颗粒、线粒体、内质网及大量糖原,该层通过发光细胞胞质内的生化反应而发光。2层均由非细胞层膜包被,间距25~30μm。发光器腹节由外向内依次为表皮、发光层、反射层和内部细胞层。幼虫发光器球形,由背射层和发光层构成,由非细胞层膜包被。背射层由单层柱状细胞构成,内含大量“尿酸囊泡”。发光层细胞膜相互绞缠,含有2种类型的发光颗粒:“致密”型和“凋亡”型,含有大量的线粒体和无定形颗粒,发光细胞之间分布着大量的气管、微气管及神经末梢,可观察到神经突触。与条背萤相比,陆生种成虫反射层和发光层均无非细胞层膜包被,2层间无明显间距,发光颗粒形状不规则,气管通常形成2分支;陆栖种幼虫发光层形状差异较大,背射层由单层或2~4层细胞构成;相似点在于,成虫发光器都由均由反射层和发光层构成,发光细胞内都含发光颗粒、线粒体及大量糖原,都具有发达的气管结构,发光颗粒相似。幼虫发光器都由背射层和发光层构成,都具有发达的气管和直接的神经支配,发光颗粒相似,都由非细胞层膜包被。  相似文献   

4.
Some ultrastructural features of the muscular coat of human small intestine   总被引:3,自引:0,他引:3  
The muscular coat of human small intestine is constituted by a 'special' layer, by the main component of the circular layer, by the region between the circular and the longitudinal layers and by the longitudinal layer. The 'special' layer is made up of the innermost 4-6 rows of muscle cells of the circular layer and is separated from the main component of the circular layer by a space in which an abundant connective tissue and numerous nerve fibers rich in nerve endings are located. Cells identified as interstitial cells of Cajal are located inside the 'special' layer, the space between it and the main component of the circular layer and in the region between the circular and the longitudinal layers. In this region small bundles of obliquely orientated muscle cells, apparently bridging the circular to the longitudinal layer, are found.  相似文献   

5.
D A Wharton 《Parasitology》1979,78(2):145-154
The egg of Aspiculuris tetraptera is an ellipsoid measuring 93 x 40 microns. The shell consists of 5 layers: the external uterine layer, internal uterine layer, vitelline layer, chitinous layer and the lipid layer. This nomenclature is based upon the formation and histochemistry of the shell layers. The internal uterine layer contains a system of interconnecting spaces, partly filled by uterine secretion, which open to the exterior of the egg via breaks in the external uterine layer. The surface of the egg is covered by a system of interconnecting grooves. Freeze-etching reveals that the internal uterine layer is open to the exterior via pores, which open into the grooves. Rod-shaped particles are also revealed in the external uterine layer. The operculum of the egg consists of a modification of the uterine and chitinous layers of the shell.  相似文献   

6.
Experiments were conducted to examine the location of oviposition by the phorid fly Megaselia halterata (Wood) (Diptera: Phoridae) in uncased and cased compost. Clearly, a majority of the gravid females choose oviposition sites directly after entering the top layer of the compost. In uncased compost, 60% of all adults emerged from the top of four compost layers of equal thickness. When the compost was covered by a casing layer which was still uncolonized by Agaricus bisporus, oviposition was further concentrated in the top compost layer. In this situation, 91% of all adults emerged from the top compost layer whereas only 1.5% emerged from the casing. When the casing layer was colonized by mushroom mycelium, 45% of all adults emerged from the casing layer and 53% emerged from the top compost layer. Further concentration in the top compost layer and the casing layer occurred as a result of upward migration of larvae. When compost was cased after oviposition, up to 43% of all adults emerged from the casing layer. We concluded that in the control of phorid infestations with insect pathogenic nematodes, applications in uncased compost can be restricted to the upper compost layer. When compost and casing are filled simultaneously, nematode applications in the casing layer only could be considered.  相似文献   

7.
宋海燕  刘再群  郑磊 《四川动物》2012,31(2):232-235,239,337
采用普通染色及免疫组化SABC染色法研究皖西白鹅小脑皮质的发育和多巴胺受体1(DRD1)阳性细胞在其发育中的表达.结果表明,小脑皮质在胚龄13 d(E13)由外向内分为外颗粒层(EGL)、浦肯野细胞层(PCL)和内颗粒层(IGL),E19由外向内分为EGL、分子层(ML)、PCL和IGL.随发育天数的增加,EGL的厚度和细胞层次呈先升后降的变化趋势,细胞密度逐渐下降;ML厚度逐渐增大,在E24到E28时增值最大;浦肯野细胞(PC)在E13、E19、E24和E28时随胚龄增大逐渐增大,在E28后趋于稳定,细胞密度随着发育天数的增加逐渐下降,在小脑皮质发育中还发现有一部分PC呈多层排列,且细胞层次逐渐变少;IGL厚度呈先升后降的变化趋势,细胞密度呈上升趋势.外颗粒层和内颗粒层在E13、E19、E24和E28时有DRD1阳性细胞表达,分子层在E24、E28、日龄7 d(P7)和15d(P15)有阳性细胞表达,PC在所检测的6个时段均有阳性表达.研究表明,小脑皮质的发育主要与细胞增殖、迁移和凋亡有关,外颗粒层的逐渐消失是以细胞迁移和凋亡为主,多层PC逐渐退化成单层是与细胞凋亡和正常突触联系的建立有关;DRD1在皖西白鹅小脑皮质发育中对外颗粒层细胞和PC起着重要作用.  相似文献   

8.
西藏色季拉山暗针叶林凋落物层化学性质研究   总被引:9,自引:1,他引:9  
The storage and chemical properties of the forest litter in dark coniferous forest of Sejila Mountain were studied. The results showed that the existing storage was 5. 863t·hm^-2 and the annual litter fall was 0. 3205 t·hm^-2 It implied that the forest litter decomposed slowly and accumulated quickly, and the turnover of nutrient circles was slow. The contents of N, Ca, Na, and Mn nutrient elements in litter layer were in the order of un-decomposed layer (U layer) > semi-decomposed layer (S layer) > decomposed layer (D layer), those of K, Fe, and Mg were in the order of D layer > S layer > U layer, and P element content was in the order of U layer > D layer> S layer. The pool of elements was 78. 483 kg·hm^-2 N, 3. 843 kg·hm^-2P, 48. 205 kg·hm^-2 K, 23.115 kg·hm^-2 Ca, 13. 157 kg·hm^-2 Na, 30.554 kg·hm^-2 Fe, 2. 113 kg·hm^-2 Mn and 27. 513 kg·hm^-2 Mg. The turnover of forest litter was the total of nutrient release accumulation. K, Fe, and Mg were enriched, and N,Ca, Na, Mn, and P were released with the turnover rate in the order of N > Ca > Na > Mn >P.  相似文献   

9.
李朝婵  钱沉鱼  全文选  唐凤华  欧静 《生态学报》2018,38(13):4909-4916
探明野生杜鹃群落不同层次土壤浸提物的化学成分及其含量差异,为阐明杜鹃群落天然更新障碍与化感作用之间的关系提供基础数据,从化学生态学角度解释群落天然更新障碍的原因。通过种子发芽试验,比较凋落物层(L层)、腐殖质层(H层)和土壤表层(S层)浸提液对自身种子萌发的化感效应,采用内标法结合气相色谱-质谱(GC/MS)联用等技术鉴定土壤浸提液所含的有机化合物。(1)种子发芽试验显示,露珠杜鹃不同土壤层浸提液的化感效应不同。L层的抑制作用最为强烈,其浸提液显著抑制自身种子的萌发。H层和S层对自身具有一定的抑制作用,与对照相比不显著;(2)鉴定了不同层次土壤浸提液中所含的有机化合物,L层、H层和S层均检测出31种组分,其中相对含量大于5%的组分分别有6、8和8种。L层浸提液主要化感成分为丙三醇和棕榈酸,分别达到总量的19.56%和19.17%;H层主要化感成分为2-羟基丙酸和棕榈酸,分别达到总量的14.05%和12.48%;S层土壤浸提物的主要化感成分为棕榈酸和2-羟基乙酸,分别达到总量的14.91%和12.79%。野生露珠杜鹃不同土壤浸提物的化感物质含量以L层最高,L层作为群落土壤化感物质的主要来源;从化感物质组分来分,长链脂肪酸和有机酸类是H层和S层主要的化感物质种类,长链脂肪酸类和醇类是L层主要的化感物质种类。杜鹃群落林下土壤中存在的化感物质可能是其天然更新障碍的重要原因之一。  相似文献   

10.
The telencephalic medial wall of the lizard Psammodromus algirus was studied using Golgi and conventional light microscopic techniques. The area is formed by two different cytological fields—medial cortex and dorsomedial cortex. These two cortices possess three layers dorsoventrally: a superficial plexiform layer, a cellular layer, and a deep plexiform layer. The alveus, a deep fiber system, runs adjacent to the ependyma. Four classes of neurons are found in the cellular layer of the medial cortex on the basis of soma shape, dendritic pattern, and position in the layer: horizontal, double pyramidal, and candelabra cells. Solitary cells are present in the superficial and deep plexiform layers of the medial cortex. Those of the superficial plexiform layer are stellate cells. Horizontal and vertical cells are found in the deep plexiform layer. Double pyramidal cells are the most frequently impregnated in the cellular layer of the dorsomedial cortex. In addition, candelabra cells are present at the lateral end of the layer. Two cell types are found in the deep plexiform layer of the dorsomedial cortex: solitary pyramidal cells and, among the fibers of the alveus, horizontal cells. Ependymal tanycytes line the ventricular surface, and protoplasmic astrocytes are found in the plexiform layers of both medial and dorsomedial cortices.  相似文献   

11.
福建永定县笔架山桫椤群落物种多样性研究   总被引:8,自引:0,他引:8  
对福建省永定是笔架山桫椤群落的不同样地,不同层次的物种丰富度,物种多样性指数和群落均匀度进行了分析。结果表明:在群落垂直结构的5个层次中,桫椤的物种多样性除物种丰富度外其他各项指标在各层次中是最大的;草本层的物种丰富度,多样性指数和种间相遇机率分居第2位,群落均匀度则居第3位;灌木层的物种丰富度居第1位,但群落均匀度最小;乔木层第1亚层的物种多样性各项指标除群落均匀度居第2位外,其他均最小;藤本的物种多样性各项指标要私居第3位,要私居第4位,样地间,乔木层,灌木层的各项多样性指标差异较小,草本层和藤本的差异较大,结果还表明;永定桫椤群落的Simpson指数和种间相遇机率(PIE)的数值几乎相等。  相似文献   

12.
为满足全国医院服务能力和医疗质量评价需求,针对复杂的病案首页源数据,设计实现了自下而上包含数据集成层、存储与管理层、分析与挖掘层、分析结果展现层,以及贯穿整个系统的数据安全和质量控制的病案首页数据集成与分布式管理平台。系统平台已应用于全国多家医院的病案首页数据的集成与处理,获得了很好的效果。  相似文献   

13.
茴香砂仁种子的解剖学和组织化学研究   总被引:3,自引:1,他引:2  
茴香砂仁种子的假种皮膜质,由内、外表皮及其间的数层薄壁细胞构成,种皮黑褐色,由外种皮、中种皮和内种皮组成,外种皮为1层表皮细胞;中种皮由1层细胞的下皮层,1层细胞的半透明细胞层、3-4层薄壁细胞的中种皮薄壁细胞层和1层细胞的色素细胞层组成,内种皮由1层径向延长的细胞构成,内切向壁与部分径向壁非常增厚,种子珠区分化出珠孔领,孔盖和珠孔区薄壁细胞,合点区内种皮出现缺口,缺口间的合点区色素细胞群整体轮廓呈刺叭状,珠孔端的则为1层细胞,细胞内含蛋白质、多糖、脂类物质,胚含量脂类物质,还含有蛋白质与多糖。  相似文献   

14.
漂白湿润淋溶土表层的有效钾、全磷、有效磷含量显著高于表下层,其它养分上下两层的含量差异尽管没有达到的显著性水平,但都有向表层集中的趋势.主分量分析结果表明,第一主分量是含氮有机质形成过程强度的量度,表层和表下层有机质、全氮、全磷、有效氮、表下层有效磷均对第一主分量有较大的正向负荷量.第二主分量表示含氮有机质形成过程强度大致相同的情况下,各种养分对红薯产量促进作用的量度,其中表层和表下层有效钾、表下层有效磷对第二主分量的负荷量最大,远远超出其它因素的作用.相关分析也表明,三者与红薯产量呈极显著正相关.这间接表明,将钾肥施入表层和表下层均能提高红薯产量,磷肥只有施入表下层才有增产效果,而氮肥目前不表现增产作用.以上结论为肥料三要素组合试验所证实.这意味着在不改变变量属性的前提下,把多个变量按照变量的特性组合成少数新变量用来解决多因素复杂问题的主分量分析方法,能够科学地、合理地指导作物施肥。  相似文献   

15.
The ultrastructural characteristics of ciliary epithelium from bovine, pigmented rabbit, and fetal albino rabbit were studied in cultured explants. The tips of ciliary processes were cultured in plastic dishes with Dulbecco Modified Eagle Medium (DMEM) containing 5% fetal bovine serum. More than half of the explants adhered to the plastic culture dish, and epithelial cells spread as monolayers within a few days. Initially the explant contains two layers, the outer (nonpigmented cells) and the inner (pigmented cells). Later the explant exhibits three layers: 1) outermost lightly pigmented flattened cells, 2) an outer layer of non-pigmented cells, and 3) an inner layer of densely pigmented cuboidal cells. The cells of the outermost layer are continuous with the cells of the inner layer. A narrow space lies between the outermost layer and the outer layer. The columnar cells in the outer layer contain well developed organelles but no pigment granules; they possess a basement membrane, lateral interdigitations, and junctional complexes near their apices. Numerous focal junctions and some ciliary channel-like structures were detected between the columnar cells of the outer layer and the cuboidal cells of the inner layer. The cuboidal cells of the inner layer are filled with pigment granules. These observations suggest that the columnar cells of the outer layer are nonpigmented epithelium, the cuboidal cells of the inner layer are pigmented epithelium, and the flattened cells in the outermost layer are derived from pigmented epithelium.  相似文献   

16.
浙江天台山七子花群落物种多样性研究   总被引:10,自引:0,他引:10  
金则新 《生态学杂志》1999,18(2):1-4,35
浙江省天台山主峰华顶山(29°15′N、121°06′E)北侧的狮子岩坑处,沿山沟两侧呈带状分布的一小片以七子花(Heptacodiummiconioides)为优势的群落。作者曾对该群落的特征和种群结构作了初步的研究[1,2]。本文通过对七子花群...  相似文献   

17.
Cell walls of Clostridium thermohydrosulfuricum and C. thermosaccharolyticum have a two-layered structure, consisting of a thin, lysozyme-sensitive murein layer and a surface (S) layer composed of hexagonally or tetragonally arranged subunits. The subunits can be removed from the murein layer by treatment of cell wall preparations, are composed of a fragile, pH-sensitive monolayer of macromolecular subunits. In both organisms the first stage of the cell division process involves only the plasma membrane and the murein layer. During the subsequent cell separation, a surplus of S-layer subunits appears at the site of division, and consequently the newly formed cell poles remain completely covered by the s layer throughout the separation process. In autolyzed cells an additional layer of subunits assembles on extended areas of the inside of the mucopeptide layer. These observations indicate that the biological function of the S layer depends on its ability to maintain a complete covering of the cell surface at all stages of cell growth and division.  相似文献   

18.
A comparative study of immunoglobulin G (IgG) immobilization was performed, both on a thiolated protein G layer, where this immobilization was due to affinity binding with an Fc fragment of IgG, and on 11-mercaptoundecanoic acid (11-MUA), where the immobilization was due to chemical bonding. The change of IgG layer formation on the two base layers as a function of the IgG concentration was investigated by surface plasmon resonance (SPR), atomic force microscopy (AFM) in a non-contact mode, and spectroscopic ellipsometry (SE). It was observed that the IgG layer was immobilized more evenly on the thiolated protein G layer than on the 11-MUA layer, based on the SPR measurements. The surface topology analysis by AFM indicated that the IgG layer was immobilized on the protein G layer according to the envelope profile of the base layer. Based on the SE analysis, it was determined that the IgG layer thickness on the thiolated protein G layer increased with increasing IgG concentration. Based on the above analyses, the scheme for orientation of IgG immobilized on the thiolated protein G layer was proposed.  相似文献   

19.
樟树人工林生态系统不同层次穿透水水化学特征   总被引:12,自引:0,他引:12  
对樟树人工林生态系统的大气降水、林冠层穿透水、灌木层穿透水和草本层滴透水中N、P、SiO2、K、Ca、Mg、Cu、Fe、Zn和Mn共10种养分元素含量进行了测定。结果表明,不同月份大气降水养分元素含量不同,各元素各月平均含量按大小排序为Ca>SiO2>Zn>NH4-N>K>NO3-N>Fe>Mg>Mn>P>Cu。大气降水经过林冠层后,林冠层穿透水、灌木层穿透水、草本层滴透水中各养分元素含量变化基本一致,均表现季节动态变化,大多数元素含量增加。林冠层穿透水、灌木层穿透水、草本层滴透水中各元素各月平均含量按大小排序分别为Ca>K>Zn>SiO2>NH4-N>NO3-N>Mg>Mn>Fe>P>Cu、Ca>K>Zn>SiO2>NH4-N>NO3-N>Mg>Fe>Mn>P>Cu和Ca>NH4-N>K>SiO2>NO3-N>Mn>Mg>Zn>Fe>P>Cu。林冠层穿透水和灌木层穿透水中Fe,草本层滴透水中Fe、Zn为负淋溶,其余各元素浓度有所增加。在上述3项中,除NO3-N、Fe、Zn外,草本层滴透水中其它养分元素的富集作用都强于其它2项。  相似文献   

20.
采用HE染色和Holmes银染法对蟾蜍中脑的显微结构进行了研究.中脑背侧,视叶可分为顶盖和被盖,顶盖从外侧到内侧依次分为:带状层、外灰质层、浅白质层、中灰质层、中白质层、深灰质层、深白质层和中央灰质.被盖前端分层与顶盖相同,后端分层不明显.中脑腹侧包括被盖和大脑脚,HE染色和Holmes银染法显示,大脑脚从外向内颜色由浅变深,存在大量纵向神经纤维束,两脚底分界处有横向交错的神经纤维.被盖外侧细胞不分层,聚集形成核团.被盖内侧,细胞和纤维以中脑水管为中心,呈同心圆环分8层.通过比较蟾蜍中脑背腹差异程度,了解背腹功能不同.同时对中华蟾蜍中脑同其他脊椎动物的进行了比较.  相似文献   

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