亚高山次生桦木林地表苔藓组成与多样性

桦木林(Betula spp.)是我国原始冷杉林(Abies spp.)皆伐后自然恢复形成的主要次生林之一,为揭示其发育过程中地表苔藓组成与多样性差异,评估其自然恢复状况,我们选择了四川省金川县507林场地形条件基本一致的3个桦木林地以及1个原始岷江冷杉(Abies faxoniana)林地,调查了地表苔藓层结构和物种组成.结果显示:(1)桦木林的地表苔藓植物盖度低于原始林,不同年龄的桦木林之间其盖度没有差异(P>0.05),但优势种的组成差异及物种替代明显;(2)桦木林地表苔藓物种丰富度较原始林高,不同年龄相比,9年生和22年生较42年生桦木林地表苔藓种类丰富;(3)未郁闭桦木林(9年生)与郁闭林(22年生和42年生)间的地表苔藓物种组成相似程度(相似性系数为0.24-0.29)低于它与原始林间的相似程度(0.51);22年生和42年生桦木林间地表苔藓物种组成相似程度(相似性系数为0.50)高于它们与原始林间的相似性程度(0.13-0.24),在自然恢复过程中,桦木林与原始林下地表苔藓共有种数量逐渐减少,相似程度降低.原始林下35种地表苔藓植物中只有25种存在于迹地桦木林地.上述分析表明:迹地上自然恢复9-42年的桦木林下地表苔藓多样性虽然较云杉人工林高,但仅保存约70%的原始林下种类,而约有29%的敏感苔藓种类无法通过次生林自然恢复过程得以保育或恢复.     

6种人工针叶幼林下地表苔藓植物层片的物种多样性与结构特征

 为了评估人工林苔藓植物发育状况,同时为人工林生态功能评价提供依据,采用样地取样方法,调查分析了岷江上游大沟流域6种人工幼龄针叶林（川西云杉(Picea balfouriana)林、日本落叶松(Larix kaempferi)林、油松(Pinus tabulaeformis)林、华山松(Pinus armandii)林、油松-华山松混交林和川西云杉-华山松混交林）林下地表苔藓植物层片物种组成、多样性以及结构特征及其异同。6种人工林下共发现了19种苔藓,各林下组成数量在7～13种。除云杉林外,纯林下苔藓种数均小于或者等于混交林下;6种人工林下地表苔藓植物平均盖度、平均密度、平均厚度分别在0.41%±1.49%～17.79%±1.67%、(27.99±367.95)～(3 807.11±412.90)株•m-2和(1.80±1.51)～(19.89±1.69) mm之间。无论是多样性指数,还是结构参数,均以川西云杉林最高,而华山松林最低。总体说来,岷江上游人工针叶幼林下地表苔藓组成物种较少、物种多样性指数（物种丰富度指数、Shannon-Wiener指数）低、Simpson指数高、结构参数（密度、盖度、厚度）较小,说明林下地表苔藓植物组成单一、结构相当简单,发育不良。综合分析表明,具有相对较低林冠郁闭度与林木密度的云杉林是6类人工林中恢复状况相对最好的类型,暗示出疏伐、修枝等管理措施可促进人工密林下地表苔藓植物生物多样性以及地表苔藓植物层片结构的改善。     

高海拔区云杉林皆伐迹地早期自然恢复进程中苔藓组成与发育程度评估

为评估皆伐迹地地表苔藓组成与特点,同时为苔藓生物多样性的保护与恢复提供理论依据,作者于2006年7–10月调查了四川省阿坝藏族羌族自治州地区壤塘二林场云杉（Picealikiangensis var.rubescens）林皆伐迹地自然恢复过程中苔藓植物和维管植物的组成和结构;采用方差分析法对苔藓层结构参数进行差异性检验,对苔藓层结构参数和环境因子作非参数Spearman相关性分析,并对显著性因子进行回归分析。结果表明：（1）在9–27年植被自然恢复过程中,不同阶段苔藓植物群落优势物种组成发生了更替。一些个体较小、易产生孢子、喜阳、抗干扰的顶蒴藓物种侵入并占据优势;而一些出现于早期采伐迹地、喜湿、对环境变化较敏感的侧蒴藓物种消失。（2）随着迹地植被自然恢复,苔藓植物群落物种丰富度、多样性指数和均匀度指数总体上呈下降趋势;迹地上样方间苔藓层盖度和生物量波动较大,但随着自然恢复进程而迅速减少,群落结构趋向简单化;（3）维管植物发育程度与苔藓层发育关系密切;草本层生物量对苔藓盖度和种丰富度起主导作用,草本层高度是对苔藓生物量有显著影响的主导因子。综合分析表明,早期采伐迹地的自然恢复进程中由维管植物群落结构变化导致的生境差异对苔藓植物发育影响较大。     

蒙古栎群落交错带(ecotone)的研究

通过群落学的样地法对蒙古栎(Quercus mongolica)群落和核桃楸(Juglans mandshurica)群落、蒙古栎群落和长白落叶松(Larix olgensis)群落、蒙古栎群落和杂灌丛群落及其交错带进行了研究,分析了在三个地点的几种群落结构和物种组成方面的差异,计算了各群落的物种丰富度指数(d_Gl)、Simpson 物种多样性指数(D)、Shannon-Weiner物种多样性指数(H′)及Pielou均匀度指数(J)。研究发现在通化和大青沟两个地区群落交错带的物种丰富度及Shannnon多样性指数最高;而在桦甸群落交错带的物种丰富度和物种多样性指数要比核桃楸群落低,比蒙古栎群落高,没有表现出特别强烈的边缘效应。本文也分析了群落乔木层、灌木层和草本层盖度之间的关系。     

高海拔幼林地表苔藓组成与结构——皆伐与造林实践的影响评估

 对壤塘县二林场4个不同时间皆伐和造林后形成的幼林地, 开展了苔藓植物和维管植物多样性调查, 采用方差分析法对苔藓植物特征进 行差异性检验, 对苔藓植物结构特征和环境因子作偏相关性分析。结果表明: 1)幼林地4个阶段的发展进程中苔藓物种组成变化显著。优势种相 似, 为喜光耐旱的侧蒴藓物种; 一些耐阴喜湿的种类种群扩大成为林下局部生境优势物种; 同时由于干扰造成地表裸露后产生耐旱土生或石生 性广泛分布的藓类。2)随着幼林地植被恢复进程, 苔藓物种丰富度(22～37)和多样性指数(0.37～1.08)呈增长趋势。结构特征在4个幼林地表现 出较强的差异性。3)乔木与灌木层盖度与苔藓植物的发育呈正相关, 灌木层盖度的发育明显促进了苔藓植物丰富度的增加, 而基于喜光先锋的 禾草为主的草本发育程度很高, 与凋落物生物量一起抑制了苔藓的发育。随幼林地发展, 乔、灌、凋落物发育性质及其相互作用发生动态变化 。因此加速幼林地乔、灌层片的发育对于促进地表苔藓植物多样性的恢复与层片发育具有重要作用。     

基于RAPD标记的丽江云杉遗传多样性及谱系地理

由于青藏高于独特的地理环境,第四纪冰期反复的退缩和扩展对目前该地区生物物种的地理分布及居群结构产生重要的影响。本文对这一地区特有分布物种丽江云杉(Picea likiangnsis)3个变种丽江云杉变种(var. likiangensis)、川西云杉变种(var. rubescens)和林芝云杉变种(var. linzhiensis)共11个种群228个个体进行RAPD分析,研究其遗传多样性及谱系地理。结果表明,该种具有较高的总体遗传多样性,多态位点达85.42%;然而在群体水平上却保持了相对低的多态性,种群间差异不显著,种群平均多态条带百分率为62.31%,Nei’s平均遗传多样性指数(H_E)为0.250,Shannon’s多样性指数(H_pop)从0.267到0.421 1。Nei’s基因多样性(G_ST=0.256)和AMOVE分析(Phi_st=0.236)表明,群体间有较高的遗传分化,群体间基因流有限(N_m=1.453 2),远远低于已报道的其它松科植物。UPGMA聚类分析表明3个形态上分离的变种没有单个聚成一枝,形成单系群。本研究认为,在第四纪冰期丽江云杉这一种在南部可能存在至少3个不同的避难所,北边和西边的居群应该是南方避难所里的居群经过不同的回迁路线而产生的,有可能是由于种内亚种间的反复杂交造成了目前的种群分布模式。     

北京野鸭湖湿地地表甲虫群落组成与空间分布格局

2007年4–10月在北京野鸭湖湿地两种保存较好的湿地植被类型和3种主要的退化植被类型中设立了32个样地, 采用陷阱法调查地表甲虫群落的组成, 并在科级水平上探讨了湿地退化及植被类型变化对地表甲虫群落组成的影响。整个采样周期共采集甲虫标本42科, 其中步甲科和隐翅虫科为优势科, 蚁形甲科、肖叶甲科和薪甲科为亚优势科。在所研究的5种植被类型中, 湿地景观保存较好的芦苇(Phragmites communis)带与球穗莎草(Cyperus glomeratus)带的甲虫群落活动密度、科丰富度和Shannon-Wiener多样性指数(H’)均无显著差异, 而上述两种植被类型的甲虫活动密度以及球穗莎草带的甲虫科丰富度均显著高于3种退化的植被类型。对地表甲虫群落组成与9个环境因子进行的典范对应分析(CCA)表明, 32个样地在CCA排序图中的分布与植被类型之间存在明显的对应关系, 土壤含水量、植物盖度、植物生物量和枯落物盖度是影响地表甲虫群落组成及空间分布的主要环境因子。相关和回归分析结果也显示, 甲虫群落的活动密度与土壤含水量、植物生物量和植物盖度均极显著或显著正相关, 科丰富度与植物生物量显著正相关, 多样性指数(H’)与植物盖度极显著负相关; 其中土壤含水量的变化能够解释甲虫群落活动密度总方差的57%。此外, 通过主成分分析获得了反映土壤含水量、植物生物量和植物盖度综合作用的环境变量WBC (Water-Biomass-Coverage)。依据地表甲虫活动密度与WBC的关系, 可将5种植被类型分为彼此差异极显著的3组。研究结果表明保持良好的湿地景观对于保护湿地甲虫具有重要意义。     

普洱市亚热带季风常绿阔叶林区蚂蚁多样性

为揭示云南省普洱市亚热带季风常绿阔叶林区蚂蚁群落多样性, 作者于2008年采用样地调查法及生物多样性分析方法研究了刺栲(Castanopsis echidnocarpa)+华南石栎(Lithocarpus fenestratus)+红木荷(Schima wallichii)群落(I)、思茅松(Pinus kesiya var. langbianensis)+小果栲(Castanopsis fleuryi)+红木荷群落(II)、披针叶楠(Phoebe lanceolata)+粗穗石栎(Lithocarpus grandifolius)+刺栲群落(III)、西南桦(Betula alnoides)+红木荷群落(IV)和人工植被(V)的地表及乔灌草层蚂蚁群落多样性。运用陷阱法采集地表蚂蚁4,660头, 隶属于7亚科61种; 运用震落法和网扫法采集乔灌草层蚂蚁1,403头, 隶属于6亚科92种。地表蚂蚁群落物种丰富度的排序为: III>II>IV>V>I, 物种多样性的排序为: III>IV>V>I>II; 乔灌草层蚂蚁群落物种丰富度的排序为: II>I>III>IV>V, 物种多样性的排序为: III>I>II>IV>V。5个样地蚂蚁群落Jaccard相似性系数在0.217–0.488, 均为中等不相似水平。思茅松+小果栲+红木荷群落(II)受到的人为干扰最严重, 急需保护; 披针叶楠+粗穗石栎+刺栲群落(III)的多样性水平最高, 具有优先保护价值。地表蚂蚁能较好地指示植物群落受干扰状况, 而乔灌草层蚂蚁能更好地指示植物多样性。     

荒漠生境油蒿根围AM真菌多样性

为了阐明荒漠生境主要植被油蒿(Artemisia ordosica)根围AM真菌多样性, 2007年8月从毛乌素沙地和腾格里沙漠选取榆林、盐池、研究站和沙坡头4个样地, 按0–10、10–20、20–30、30–40、40–50 cm 5个土层采集油蒿根围土壤样品, 研究了油蒿根围AM真菌物种多样性和生态分布。在分离的4属28种AM真菌中, 球囊霉属(Glomus)16种, 无梗囊霉属(Acaulospora)7种, 盾巨孢囊霉属(Scutellospora)4种, 多孢囊霉属(Diversispora)1种。4个样地的共同优势种为摩西球囊霉(G. mosseae), 共同常见种为双网无梗囊霉(A. bireticulata)和网状球囊霉(G. reticulatum), 共同稀有种为缩球囊霉(G. constrictum)。地球囊霉(G. geosporum)仅出现在盐池, 蜜色无梗囊霉(A. mellea)、帚状球囊霉(G. coremioides)、浅窝无梗囊霉(A. lacunosa)和宽柄球囊霉(G. magnicaule)仅出现在研究站, 黑球囊霉(G. melanosporum)仅出现在榆林。盐池与研究站样地AM真菌种类最多, 榆林样地孢子密度最大, 沙坡头样地种类和孢子密度显著偏低。总体上, 孢子密度、分离频度、相对多度和重要值依Glomus >Acaulospora > Scutellospora> Diversispora呈现显著减小趋势。结果表明, 油蒿与AM真菌之间有良好共生性, 这对进一步利用菌根生物技术维护荒漠生态系统结构的完整性具有重要意义。     

天山北部拟南芥生存群落特征及其与环境的关系

为了解拟南芥在天山北部的分布状况及环境依赖特点, 分析拟南芥的自然选择特征, 本文对天山北部分布的13个拟南芥(Arabidopsis thaliana)生存群落结构、组成及其与环境关系进行了研究, 并分析了拟南芥与群落主要物种的种间联结性。结果表明: 拟南芥生存的群落结构简单, 其中天山北坡中段的石河子、一四三团、沙湾、独山子地区的8个群落均为草本类型, 优势种相似, 而与伊犁果子沟、额敏和阿勒泰的5个群落差别较大。属的区系成分分析表明世界分布、北温带分布以及地中海、西亚至中亚分布型成分占大多数, 具有典型的地中海旱生植物区系分布特征, 体现了本地拟南芥分布及演化的干旱、半干旱的地理环境特点。采用双向指示种分析(TWINSPAN)将13个群落分为新疆绢蒿–猪毛菜–角果毛茛(Seriphidium kaschgaricum–Salsola collina–Ceratocephalus testiculatus)、新疆绢蒿–猪毛菜(S. kaschgaricum–S. collina)、新疆绢蒿–狭果鹤虱(S. kaschgaricum–Lappula semiglabra)、新疆绢蒿–旱麦草(S. kaschgaricum–Eremopyrum triticeum)、勿忘草–草原苔草(Myosotis sylvatica–Carex liparocarpos)5个群落类型。去势典范对应分析(DCCA)表明纬度、坡向、土壤有机质及pH值是决定天山北部拟南芥种群分布的主导因子。拟南芥分布与群落内其他物种有极强的依赖关系, 与13个群落62个主要物种的种间联结性分析表明, 共有119个正关联性种对, 明显高于72个负关联性种对, 与各群落优势种呈显著正关联。拟南芥种群分布数量在群落间差异较大, 分布于降雨较少的天山中部浅山地带拟南芥种群数量均高于降雨较丰富的天山西部伊犁果子沟地区, 是否发生适应性分化需要深入研究。     

Anthropology and genetics of the caucasus peoples and the problem of the origin of the caucasoids

The electrophoretical polymorphisms of some blood proteins were studied in the Talysh population of Pirasora situated in South-East Azerbaidjan. We calculated the gene frequencies of these polymorphisms and determined the genetic distances between the Talyshes and some Iranian populations of North, Central and South Iran, Afghans, and three populations of Azerbaijan. The Talyshes are very close to Iranians of Shiraz, whereas they are distant from the Azerbaijanians. Anthropological investigations showed that the Caucasoids and Mongoloids lived in the Aragvi Basin since the Eneolithic period. This was stated by Alexeev (1974), who emphasized the mixture of the Caucasus populations from ancient times on. We calculated the genetic distances between the Caucasus populations and numerous populations of other geographic regions, considering 28 alleles of 12 loci of blood group, serum protein and red cell enzyme polymorphisms and constructed the dendrogram of these populations. The position of the Caucasus populations in the dendrogram corresponds on principle to the earlier anthropological observations. The clustering of the Caucasoid populations corresponds completely with anthropological and historical data, and supports our earlier hypothesis (Nazarova 1999) concerning the differentiation of Caucasoids, Northern Mongoloids and Amerinds from the populations, which inhabitated Asia in palaeolithic times.     

Kinematics and dynamics of the temporomandibular joint and of the movements of the mandible

In order to analyze the complicated movements of the mandible as the open-closing movement and the protrusio are, it is useful to evaluate the basic kinematic principles and reduce them to simple technical constructions. Both the open-closing movement and the protrusio could be reduced to 4-bar links, which were used to simulate the movements with help of a computer. Besides, the polodes and the curves of points in the muscular attachments could be constructed. The 2 entirely different 4-bar links have 3 things in common: The resting system - cranium, the moving system - mandibula, and 1 of the 2 arms connecting these 2 systems - the ligamentum laterale. As this ligament is taut during movements it can be considered a "guiding ligament" representing 1 of the 3 determining components of the mandibular movements. The other of the 2 arms has no anatomical equivalent; this arm, however, is "replaced" by the 2 other determining components of the mandibular movements: the joint and the muscles. The curves, which the Caput mandibulae describes, are practically identical for the open-closing movement and the protrusio despite of the different 4-bar links and these curves exactly correspond to the Discus articularis, taut by the upper part of the M. pterygoideus lateralis. The muscles do not only just move the mandibula, but they are also the component, which can choose between the different mandibular movements. By means of the curves, which points in the muscular attachments describe, the function of the masticatory muscles could be analyzed exactly.     

On the structure and dynamics of the complex of the nucleosome and the linker histone

Several different models of the linker histone (LH)–nucleosome complex have been proposed, but none of them has unambiguously revealed the position and binding sites of the LH on the nucleosome. Using Brownian dynamics-based docking together with normal mode analysis of the nucleosome to account for the flexibility of two flanking 10 bp long linker DNAs (L-DNA), we identified binding modes of the H5-LH globular domain (GH5) to the nucleosome. For a wide range of nucleosomal conformations with the L-DNA ends less than 65 Å apart, one dominant binding mode was identified for GH5 and found to be consistent with fluorescence recovery after photobleaching (FRAP) experiments. GH5 binds asymmetrically with respect to the nucleosomal dyad axis, fitting between the nucleosomal DNA and one of the L-DNAs. For greater distances between L-DNA ends, docking of GH5 to the L-DNA that is more restrained and less open becomes favored. These results suggest a selection mechanism by which GH5 preferentially binds one of the L-DNAs and thereby affects DNA dynamics and accessibility and contributes to formation of a particular chromatin fiber structure. The two binding modes identified would, respectively, favor a tight zigzag chromatin structure or a loose solenoid chromatin fiber.     

人类基因组及后基因组研究进展及其应用与开发研究现状

人类对自身基因组的研究,随着人类基因组工作草图的绘制完成和对基因功能研究的深入已加快进入了实质性、关键性的开发利用阶段。本文概述了人类基因组及后基因组的研究进展及依此开展基因治疗及基因（组）药物研制等应用开发研究的现状。     

Biophysics and Structure of the Patch and the Gigaseal

Interpreting channel behavior in patches requires an understanding of patch structure and dynamics, especially in studies of mechanosensitive channels. High resolution optical studies show that patch formation occurs via blebbing that disrupts normal membrane structure and redistributes in situ components including ion channels. There is a 1-2 μm region of the seal below the patch where proteins are excluded and this may consist of extracted lipids that form the gigaseal. Patch domes often have complex geometries with inhomogeneous stresses due to the membrane-glass adhesion energy (E_a), cytoskeletal forces, and possible lipid subdomains. The resting tension in the patch dome ranges from 1-4 mN/m, a significant fraction of the lytic tension of a bilayer (∼10 mN/m). Thus, all patch experiments are conducted under substantial, and uneven, resting tension that may alter the kinetics of many channels. E_a seems dominated by van der Waals attraction overlaid with a normally repulsive Coulombic force. High ionic strength pipette saline increased E_a and, surprisingly, increased cytoskeletal rigidity in cell-attached patches. Low pH pipette saline also increased E_a and reduced the seal selectivity for cations, presumably by neutralizing the membrane surface charge. The seal is a negatively charged, cation selective, space with a resistance of ∼7 gigohm/μm in 100 mM KCl, and the high resistivity of the space may result from the presence of high viscosity glycoproteins. Patches creep up the pipette over time with voltage independent and voltage dependent components. Voltage-independent creep is expected from the capillary attraction of E_a and the flow of fresh lipids from the cell. Voltage-dependent creep seems to arise from electroosmosis in the seal. Neutralization of negative charges on the seal membrane with low pH decreased the creep rate and reversed the direction of creep at positive pipette potentials.     

Serology and systematics of the Ebenales and the Theales

The systematic position ofthe Ebenaceae, Sapotaceae, Styracaceae, Ochnaceae, Stachyuraceae, Dipterocarpaceae, Clusiaceae and Hypericaceae has been investigated using serological comparisons of sets of antigenic determinants. The results show that the Sytracaceae and Sapotaceae are undoubtedly more closely associated with the Actinidiaeceae and Theaceae, respectively, than with each other. We found no corresponding determinants betnween antigen systems from the Ebenaceae and systems from any other family whose relations to this family have been proposed. As discovered previously, investigations of antigen systems from the Ochnaceae, Dipterocarpaceae, Stachyuraceae, Clusiaceae and Hypericaceae are against the idea of a natural order “Theales” in which these families, or at least some of them, are combined with the Theaceae and Actinidiaceae. This paper completes our previous investigations which largely support a superorder Ericanae sensu Ehrendorfer and Takhtajan. We propose to include the Actinidiaceae and Theaceae in this superorder, assigning them a central position laong with the Sapotaceae and Sytracaeae on one side and the Primulales and Ericales on the other. Another most interesting finding is that there are corresponding determinants between antigen systems from the members of the Ericanae and representatives of the Polemoniaceae and Loasaceae.     

Comparison of the Effects of Flexion and Extension of the Thumb and Fingers on the Position and Cross-Sectional Area of the Median Nerve

Objective

To assess the separate effects of thumb and finger extension/flexion on median nerve position and cross-sectional area.

Methods

Ultrasonography was used to assess median nerve transverse position and cross-sectional area within the carpal tunnel at rest and its movement during volitional flexion of the individual digits of the hand. Both wrists of 165 normal subjects (11 men, 4 women, mean age, 28.6, range, 22 to 38) were studied.

Results

Thumb flexion resulted in transverse movement of the median nerve in radial direction (1.2±0.6 mm), whereas flexion of the fingers produced transverse movement in ulnar direction, which was most pronounced during flexion of the index and middle fingers (3.2±0.9 and 3.1±1.0 mm, respectively). Lesser but still statistically significant movements were noted with flexion of the ring finger (2.0±0.8 mm) and little finger (1.2±0.5 mm). Flexion of the thumb or individual fingers did not change median nerve cross-sectional area (8.5±1.1 mm²).

Conclusions

Volitional flexion of the thumb and individual fingers, particularly the index and middle fingers, produced significant transverse movement of the median nerve within the carpal tunnel but did not alter the cross-sectional area of the nerve. The importance of these findings on the understanding of the pathogenesis of the carpal tunnel syndrome and its treatment remains to be investigated.     

Schistosoma haematobium: the effect of Astiban on the cell composition and ultrastructure of the vitelline gland and the ultrastructure of the tegument and gastrodermis

Treatment of Schistosoma haematobium (Nigerian strain) in hamsters with a single dose of 40 mg/kg of Astiban caused a reduction in the number of S1, S2, and S3 vitelline cells and an increase in S4 cells. Following seven daily doses of the drug, a marked reduction in S1 cells and a complete loss of S2 and S3 cells occurred such that 95% of the cells were S4 cells, all of which were structurally abnormal. Coagulation and disintegration of the protein granules of the vitelline droplets occurred with increase in lipid droplets, swelling of the nuclear membrane and an increase in cytosegresomes. Blebbing of the tegument in both sexes occurred following a single treatment and vacuolation of the basal infolds and alterations to the mitochondria also resulted, but severe erosion of the tegument was rare even following repeated drug treatment. Damage to the gastrodermis was severe with the development of autophagic vacuoles containing whorls of myelin and sequestered portions of damaged tissue. The degree of damage increased with the number of drug treatments.