359 resultados para Tibet


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青藏高原为冷杉属(Abies)的多度中心,共分布有10种,9变种和4亚种。其中苍山冷杉复合体(Abies delavayi complex)包括3种,5变种和2亚种。它们的形态性状变异较小,且分布区重叠。迄今对该复合体的遗传多样性水平、分化程度以及进化历史仍缺乏了解。 本研究对苍山冷杉复合体的14个居群、302个个体进行取样,并对193个个体的母系遗传线粒体DNA nad1 intron2区和276个个体的父系遗传的叶绿体DNA trnS-trnG区进行了序列分析。该复合体的线粒体DNA nad1 intron2区的序列为675bp,其中有4个单碱基变异和1个插入/缺失,可分为6种线粒体单倍型。这14个居群的线粒体总核苷酸多态性(π)为0.00114,单倍型多态性(Hd)为0.627,居群间的遗传变异(FST)高达84.034%。叶绿体DNA trnS-trnG区的序列排列后为718bp,共有8个单碱基变异和4个插入/缺失,可分为12种叶绿体单倍型。这14个居群的总核苷酸多态性(π)为0.00116,单倍型多态性(Hd)为0.590,居群间的遗传变异(FST)为65.830%。以上结果显示苍山冷杉复合体居群间已经产生了强烈的遗传分化。叶绿体的3种主导单倍型(H1、H2和 H3)在YLXS、SKXS、GS和WX 4个居群中都有分布;而其它居群则只有主导单倍型(除SJLS外)中的1种或2种。造成边缘居群(如JZS)多样性较低的主要原因是冰期后群体在迁移过程中的遗传漂变和奠基者效应。根据谱系关系线粒体H1型和叶绿体H3型均为较古老的单倍型,线粒体和叶绿体的谱系关系均支持上述分析。 本研究初步推测青藏高原的东南部—横断山区(包括YLXS、SKXS、GS、WX、BMXS、ELS和EMS)可能为苍山冷杉复合体的冰期避难所,群体存在冰期后向西和向南扩张的过程。间冰期群体隔离和扩张过程中的奠基者效应是形成目前居群分化和遗传多样性分布格局的重要因素。

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本文通过在林周唐古地区的定位性调查和历史资料的分析,对红景天植物的资源生态学特性进行了如下几个方面的探讨和研究。 1、分析了调查区的自然概况,探讨了调查区红景天的地理分布规律及特点。 2、对调查区的植被进行分析,划分了22个群落种组,八个群落类型。并对群落种组,群落学特征进行了分析。同时,还探讨了群落的分布规律以及生态系统与环境因子的关系。 3、分析了红景天种子的生物学特性、种子的撒播、萌发和幼苗建成过程以及自然条件下的无性繁殖方式。并进一步的也进行了人工繁殖实验。 4、通过物种间关系的研究,对三种红景天的指示植物种进行了初步确定,其结果在种的排序图上得到了进一步的分析和解释。 5、对红景天不同部位化学成分的测定结果表明:不同部位化学成分的分布量不同。建议开发利用过程中,应根据利用目的针对性开发。 6、对不同海拔带的红景天生物量进行了测定分析,并对其生长过程进行了生物量的动态研究和生长分析。 7、就红景天植物资源的利用历史、利用现状和开发利用过程中存在的问题做了概括性论述。并对今后合理利用和保护等问题提出了一些建议。

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青藏高原是世界上最高的高原,被称为“地球第三极”,环境条件相当严酷。本研究通过ISSR标记的方法研究青藏高原两种相对克隆构型的克隆植物紫花针茅(Stipa purpurea Griseb.)和青藏苔草(Carex moorcroftii Falc. ex Boott)不同种群的遗传多样性及克隆格局,在分子水平上揭示两种植物对极端环境适应的机理。主要结果如下: 与其它针茅属植物相比,紫花针茅各种群平均遗传多样性相对较低,其遗传变异主要存在于种群之内;与其它苔草属植物相比,青藏苔草各种群平均遗传多样性也较低,而总的遗传多样性较高,其遗传变异主要存在于种群之间。紫花针茅各种群平均遗传多样性高于青藏苔草各种群平均遗传多样性,尽管差异不显著。紫花针茅和青藏苔草各种群间具有较高的遗传分化。 紫花针茅具有与其它分蘖型克隆植物相当的克隆多样性,说明有性生殖在其生活史中起着重要作用。青藏苔草具有与其它克隆植物相当的克隆多样性,而与北极地区苔草属植物相比,其克隆多样性则较低。 Pearson相关显示,紫花针茅遗传多样性与纬度、经度均成显著负相关,而与海拔高度相关关系不显著;青藏苔草克隆多样性及遗传多样性与纬度、经度、海拔高度均不相关,而克隆多样性与遗传多样性的比值则与纬度显著相关。唐古拉山对紫花针茅遗传格局未产生显著影响,山南北地区遗传多样性无显著差别;唐古拉山对青藏苔草遗传格局产生了重要影响,唐古拉山南北地区基因交流有显著隔离,唐古拉山以北地区种群遗传多样性显著高于以南地区,推测其种群自北向南迁移过程中的瓶颈效应起着重要作用。青藏苔草种群的克隆多样性与遗传多样性成显著正相关。Mantel test检验显示,紫花针茅和青藏苔草的地理距离与遗传距离间的关系均不显著。 紫花针茅以分蘖生长的方式由源株向外扩展,有明确、致密的边界,野外观察和室内检测的结果显示其环上其它基株也可进行生长成活,可形成一种克隆环镶嵌格局,克隆环或其边界可能是幼苗定居有利的生境;空间自相关也显示在较小的尺度内紫花针茅遗传相关性强,推测克隆繁殖在其中也起重要作用。青藏苔草种群不同尺度的取样其克隆多样性不同,小面积(1 × 1 m2)的克隆多样性均小于大面积的(10 × 10 m2),空间自相关也显示克隆生长在其中起重要作用;尽管青藏苔草有较强的克隆生长能力,在环境条件较好时其呈密集分布,表现出较强的可塑性。 总之,尽管青藏高原环境非常严酷,紫花针茅与青藏苔草仍有较高水平的克隆多样性和一定的遗传多样性;高原严酷的环境造成了两种植物较大的遗传隔离。紫花针茅环状结构对其有性更新有重要作用,青藏苔草克隆生长具有较大可塑性,这些都是植物对高原严酷环境的适应形式。

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通过气体交换、荧光猝灭动力学以及反射光谱等技术研究了两个青稞(Hordeum vulgare L.)品种的光合特性及激发能分配。结果表明,青稞的光饱和点1000 μmol m-2 s-1左右。在0~500 μmol m-2 s-1的光强范围里,青稞叶片的光呼吸(Pr)随着光强升高而增加;光强超过500 μmol m-2 s-1以后,光呼吸变化不明显。光呼吸占总光合的比例(Pr/Pm)随光强增强下降。随着光强增强,PSⅡ有效光化学量子效率(Fv′/Fm′),PSⅡ反应中心的实际光化学量子效率(ΦPSⅡ),光化学猝灭系数(qP)不断降低而青稞叶片的非光化学猝灭(NPQ)不断升高,说明越来越多的光能以热耗散的形式耗散掉。光谱分析表明△PRI 随着青稞叶片暴露于光下的时间迅速增大。因此,我们认为光呼吸不是青稞主要的光破坏防御机制,依赖叶黄素循环的热耗散可能是田间青稞耗散过剩光能的主要途径。 通过气体交换、荧光猝灭动力学等技术研究了四种乔木在拉萨和那曲的光合特性及激发能分配。结果表明,四种乔木藏川杨(Populus szechuanica var. tibetica schneid.),银白杨(Populus alba L.),左旋柳(Salix paraplesia var. subintegra C. Wang et P. Y. Pu),墨竹柳(Salix maizhokunggarensis N. Chao)在拉萨市的光合速率(Pn),叶片气孔导度(Gs),蒸腾速率(Tr)均显著高于那曲。藏川杨和墨竹柳的光下实际光化学效率(ΦPSⅡ)在拉萨显著高于那曲,银白杨和左旋柳的光下实际光化学效率在拉萨和那曲没有显著差异。四种乔木开放反应中心激发能捕获效率(Fv′/Fm′)和天线热耗散(1-Fv′/Fm′)在拉萨和那曲的差异不显著。测量光合时的气温(Tair)拉萨显著高于那曲,除墨竹柳外叶温(Tleaf)也显著高于那曲,墨竹柳的上述两参数在两地间无显著差异。除藏川杨外其余三种乔木在拉萨的胞间二氧化碳浓度(Ci)显著高于那曲,气孔限制值(Ls)显著低于那曲,藏川杨的上述两指标在两地间无显著差异。除墨竹柳外,其余三种乔木在两地的光合(Pn)与叶温(Tleaf)成显著正相关。对银白杨和左旋柳来说,低叶温通过降低气孔导度(Gs)从而降低胞间二氧化碳浓度(Ci)是造成那曲光合低的主要因素之一。对于墨竹柳来说,可能有其他非温度的环境条件影响其气孔导度进而造成气孔限制。此外,叶温可能主要通过非气孔限制来影响藏川杨的光合速率。因此,我们认为在西藏地区不同乔木对海拔高度的响应机制可能不同,但具体机制还需要进一步研究。

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By using 19 Y chromosome biallelic markers and 3 Y chromosome microsatellite markers, we analyzed the genetic structure of 31 indigenous Sino-Tibetan speaking populations (607 individuals) currently residing in East, Southeast, and South Asia. Our results showed that a T to C mutation at locus M122 is highly prevalent in almost all of the Sino-Tibetan populations, implying a strong genetic affinity among populations in the same language family. Furthermore, the extremely high frequency of H8, a haplotype derived from M122C, in the Sino-Tibetan speaking populations in the Himalayas including Tibet and northeast India indicated a strong bottleneck effect that occurred during a westward and then southward migration of the founding population of Tibeto-Burmans. We, therefore, postulate that the ancient people, who lived in the upper-middle Yellow River basin about 10,000 years ago and developed one of the earliest Neolithic cultures in East Asia, were the ancestors of modem Sino-Tibetan populations.

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The phylogenetic relationships among worldwide species of genus Ochotona were investigated by sequencing mitochondrial cytochrome b and ND4 genes. Parsimony and neighbor-joining analyses of the sequence data yielded congruent results that strongly indicated three major clusters: the shrub-steppe group, the northern group, and the mountain group. The subgeneric classification of Ochotona species needs to be revised because each of the two subgenera in the present classification contains species from the mountain group. To solve this taxonomic problem so that each taxon is monophyletic, i.e., represents a natural clade, Ochotona could be divided into three subgenera, one for the shrub-steppe species, a second for the northern species, and a third for the mountain species. The inferred tree suggests that the differentiation of this genus in the Palearctic Region was closely related to the gradual uplifting of the Tibet (Qinghai-Xizang) Plateau, as hypothesized previously, and that vicariance might have played a major role in the differentiation of this genus on the Plateau, On the other hand, the North American species, O. princeps, is most likely a dispersal event, which might have happened during the Pliocene through the opening of the Bering Strait. The phylogenetic relationships within the shrub-steppe group are worth noting in that instead of a monophyletic shrub-dwelling group, shrub dwellers and steppe dwellers are intermingled with each other. Moreover, the sequence divergence within the sister tars of one steppe? dweller and one shrub dweller is very low. These findings support the hypothesis that pikes have entered the steppe environment several times and that morphological similarities within steppe dwellers were due to convergent evolution. (C) 2000 Academic Press.

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黑白仰鼻猴(Rhinopithecus bietz)分布在我国金沙汀和澜沧江之间的横断山脉的一个狭小区域内(26°14'N-29°20'N,99°15'E-99°37'E),海拔分布范围2600(南部)-4200m(北部);目前大约有15群,约1700只.本文所研究的西藏米拉卡猴群分布在我国西藏藏族自治区芒康县的南部,数量约50只.基于野外调查和过去的报道,此地的暗针叶林和针阔叶混交林是猴群的适宜栖息地,而由于人口数量增加所导致的夏季牧场和农田面积不断扩增正在逐渐侵蚀着这里的暗针叶林.为了评估该猴群的柄息地现状、变化趋势和变化原因,我们通过野外调查工作,利用GIS和RS技术,分别解译了当地过去5年(1986-2006年)冬季的Landsat TM卫星影像,并对解译结果进行了分析和计算,得到了该猴群栖息地的主要结果有:1)2006年暗针叶林面积是13600hm2,夏季牧场面积是4900hm2,农田面积是3300hm2;2)在过去20年(1986-2006年),暗针叶林面积减少了15.5%(2500hm2),牧场面积增加了58.1%(1 800hm2),农田面积增加了17.8%(500hm2);3)暗针叶林的斑块数量增加了75.6%,平均斑块面积下降了51.8%(从1986年的15.3hm2到2006年的7.4hm2),最大斑块指数下降了54.7%;景观丰富度并没有变化,但Shannon多样性指数和Shannon均匀度指数分别增加了4.0%;4)暗针叶林面积变化与当地的人口数量呈显著负相关(r=-1.000),而夏季牧场和农田面积分别和当地人口呈显著正相关(r=1.000).表明黑白仰鼻猴米拉卡猴群栖息地的丧失和破碎化程度较为严重;栖息地丧失和破碎化是当地传统生产方式和人口增长共同作用的结果.

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Random amplified polymorphic DNA (RAPD) markers are used to investigate genetic variation and evolutionary relationships of 29 samples of Cordyceps sinensis from different geographical populations on the Qinghai-Tibet plateau. Out of 137 RAPD bands scored, 100 are polymorphic. A correlation is revealed between geographical distance and genetic distance. The molecular phylogenetic tree suggests that the 29 samples are divided into three notable clusters, corresponding to the geographical populations, i.e., the north population (NP), middle population (MP), and south population (SP). The NP consists of 7 northern samples from Menyuan, Maqu, and Luqu, the MP consists of 8 samples from Yushu and Chengduo, and the SP consists of 14 samples from Byma Snow Mountain, Renzhi Snow Moutain, Chongcaoxiwa, and Dacaodi. It is demonstrated that extensive genetic diversity is found among different geographical populations of C. sinensis. The genetic diversity pattern of C. sinensis may be caused by the founder effects. The taxonomic status of NP, MP, and SP populations should be that they are different subspecies rather than different species.

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The phylogenetic relationship of several subspecies of Ovis ammon were analyzed by comparing DNA sequences within the entire mitochondrial D-loop region. Five putative subspecies of ammon (dalai-lamae, darwini, hodgsoni, sairensis and adamerzi) were sampled from four provinces in China [Xinjiang, Qinghai, Gansu and Xizang (Tibet)] and two (servertzovi and nigrimontana) from Uzbekistan. The argalis sampled represent most of the currently recognized putative Subspecies of argali. Analysis of mtDNA sequences revealed high variability within ammon (7.7%), ranging from 2.4 to 11.5%. MaxiMUM-Parsimony tree indicated that nigrimontana from Uzbekistan diverged First, followed by severtzovi from Uzbekistan. The dispersal of argalis into China gave rise to three clades, suggesting that the argali originated in Western Asia and then dispersed throughout the central Asian highlands on a southeastward course. Among the Chinese argalis, mtDNA analysis places dalailamae genetically closer to hodgsoni than to darwini. Severtzovi and.. nigrimontana are two separate subspecies and genetically distinct from the Chinese argali.

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To search for compounds with superior anti-human immunodeficiency virus type 1 (HIV-1) activity, ten 5,5'-(p-phenylenebisazo)-8-hydroxyquinoline sulfonates (4a-j) were synthesized and preliminarily evaluated as HIV-1 inhibitors in vitro for the first time. Some compounds demonstrated anti-HIV-1 activity, especially 5,5'-(p-phenylenebisazo)-8-hydroxyquinoline p-ethylbenzenesulfonate (4g) and 5,5'-(p-phenylenebisazo)-8-hydroxyquinoline p-chlorobenzenesulfonate (41) showed the more potent anti-HIV-1 activity with 50% effective concentration (EC50) values of 2.59 and 4.01 mu g/ml, and therapeutic index (TI) values of 31.77 and 24.51, respectively.

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在西藏墨脱采集到1种与Odorrana graminea、O.chloronota和O.livida体背绿色和指端膨大具沟的湍流蛙类相近的物种,经鉴定为新种,命名为墨脱臭蛙Odorrana zhaoi.新种具有以下主要特征:上唇缘具有金黄色条纹;鼓膜圆形,显著,TD:ED为0.56;背侧褶弱,背部皮肤除后部有小疣粒外光滑,体侧有疣粒和小刺;4肢背面有横斑纹;无外蹠突;雄性具1对外声囊和咽胸部椭圆形小刺团,无肱腺.

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In order to understand how mandibular structure differs among the Chinese cercopithecoids (Rhinopithecus, Trachypithecus and Macaca), particularly the uniqueness of the snub-nosed monkeys (Rhinopithecus), we analysed ten mandibular measurements by principal components analysis (PCA), and examined scaling patterns. The results provided by the PCA illustrated differences due to size among the cercopithecoids and the relationship between colobines (Trachypithecus and Rhinopithecus) and cercopithecines, in which macaques (Macaca) are included. Allometric analysis indicated that, biomechanically, there is not a marked difference between macaques and leaf-eating monkeys. This may be associated with the fact that both share some similar ecology and niches in south and southwest China. The snub-nosed monkeys exhibit a significantly more robust mandible, evident in the symphysis, corpus, condyle, and masticatory momentum arm. This supports the hypothesis, based on the study of dental structure, that Rhinopithecus is a unique group in Asian Old World monkeys (OWMs) and has developed some unique characteristics in order to adapt to the tough food available in the severe cold climate of the Plateaux of Qinghai-Tibet, Yun-Gui and Qingling in China.

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 通过两次考察,证实西藏芒康县目前存在3个滇金丝猴群,即小昌都群、米拉卡群和木尼群,个体数 量约为300~400只。另有一个群,即下火拉群尚待证实。其中,小昌都群是芒康的最大猴群,其数量约为160~ 200只。芒康滇金丝猴以地衣为主要食物,所占比例可达47%~64% ,而其社会结构与云南各群一致,为多个单雄 多雌群(OMU)聚合为大群。这说明生境和食性等生态学差异并未改变滇金丝猴的社会结构。日趋严重的生境破 碎化和人类活动干扰对滇金丝猴的生存构成了威胁,加强芒康地区的滇金丝猴保护区的建设和管理是目前最急迫 的保护对策。

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In order to study the differentiation of Asian colobines, 14 variables measured on 123 skulls, including Rhinopithecus, Presbytis, Presbytiscus (Rhinopithecus avunculus), Pygathrix and Nasalis were analyzed by one-way, cluster and discriminant function analyses. Information on paleoenvironmental changes in China and southeast Asia since the late Tertiary was used to examine the influences of migratory routes and range of distribution in Asian colobines. A cladogram for 6 genera of Asian colobines was constructed from the results of various analyses. Some new points or revisions were suggested: (1) Following one of two migratory routes, ancient species of Asian colobines perhaps passed through Xizang (Tibet) along the northern bank of the Tethys sea and through the Heng Duan Shan regions of Yunnan into Vietnam. An ancient landmass linking Yunnan and Xizang was already present on the east bank of the Tethys sea. Accordingly, Asian colobines would have two centers of evolutionary origin: Sundaland and the Heng Duan Shan regions of China. (2) Pygathrix shares more cranial features with Presbytiscus than with Rhinopithecus. This differs somewhat from the conclusion reached by Groves. (3) Nasalis (karyotype: 2n = 48) may be the most primitive genus among Asian colobines. Certain features shared with Rhinopithecus, e.g. large body size, terrestrial activity and limb proportions, can be interpreted as symple-siomorphic characters. (4) Rhinopithecus, with respect to craniofacial features, is a special case among Asian colobines. It combines a high degree of evolutionary specialization with retention of some primitive features thought to have been present in the ancestral Asian colobine.

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Black-and-white snub-nosed monkeys (Rhinopithecus bieti) are endemic to the Trans-Himalayas in Northwest Yunnan and Southeast Tibet between the upper Yangtze and Mekong Rivers. Based on field surveys and previous reports, we identified the dark-coniferous forest, the mixed coniferous and broadleaf forest, and oak patches as suitable habitats (SH) for the monkeys. Summer grazing lands (SGL), which were made by local people cutting and burning the dark-coniferous forest at the high altitude belt, replaced SH. To have a general view of the status of the SH in Yunnan, we estimated the areas of SH and SGL from satellite images in 1997, and compared with areas estimated from aerial photo-based maps (ca. 1958). The work resulted in: 1) the area of SH was 4,169 km(2) in 1997; 2) SGL was 1,923 km(2); 3) during the past 40 years, the area of SH decreased by 31% (1,887 km(2)), and SGL increased by 204% (1,291 km(2)); and 4) the mean size of forest patches decreased from 15.6 to 5.4 km(2). In addition, the area of SGL is positively correlated to local human population (R-2 greater than or equal to0.53), implying that the reduction and fragmentation of habitat for Rhinopithecus bieti is a result of population growth of humans, who mostly employ traditional modes of production. Only 11 monkey groups remained in the changing habitat. Considering that forests at lower elevation were also encroached upon by farmlands in a similar way, the forest ecosystem is highly threatened. The destruction will continue unless there is a change in the mode of production in the region.