【作者】 王一峰；

【导师】 杜国祯；

【作者基本信息】 兰州大学 ， 生态学， 2009， 博士

【摘要】 青藏高原高寒草甸是一个独特的生态系统,其特殊的地理区域和气候条件,孕育了许多种独特的植物类群。风毛菊属植物主要分布于横断山至青藏高原及其边缘地区,为高寒草甸重要组成植物,本项目以分布在青藏高原东缘（甘肃）的风毛菊属植物为材料,从形态学水平（对植物体各器官的描述和测量）,器官水平（叶的形态解剖特征,花粉的电镜扫描,种子表皮纹饰等）、细胞水平（染色体数目观察、核型分析）、生态学研究并结合区系地理分析对青藏高原东缘风毛菊属植物进行较为系统全面的研究,以期对风毛菊属植物系统演化、属内分类单位的系统位置和生态适应机制等方面的研究提供理论依据,其结果不但对解决风毛菊属植物系统演化、属内分类单位系统位置和生态适应机制具有重要意义,而且,对资源植物的利用方面亦具有十分重要意义。主要结论如下:1.本地区风毛菊属植物共有36种,隶属于4个亚属,占全国总种数的13.64%,占甘肃总种数的62.07%,多样性程度高。2.本研究区风毛菊属植物有三个分布的丰富区,分别位于33.8°N、102°E; 34.3°N、103°E和35°N、103°E附近。3.青藏高原东缘风毛菊属植物可划为4个分布型和1个变型,区系成分以温带成分为主,同时,甘肃特有种和中国特有种比例较高。4.推测中亚至喜马拉雅一带为风毛菊属植物的起源中心。5.风毛菊属植物的气孔类型为无规则型,表皮细胞的形状为多边形或不规则形,垂周壁为平直、弓形或波状弯曲,下表皮气孔的长宽比大约在1.10-1.54之间,气孔密度在61.35 -410.43mm^-2之间,气孔指数在11-30%之间。6. 25种风毛菊属植物中只有星状雪兔子为等面叶且无表皮毛,其余24种植物均为异面叶且都有表皮毛;表皮细胞单层,角质层厚;叶肉的栅栏组织和海绵组织中普遍形成发达的通气组织。这表明了25种植物的叶片既具有中生植物又兼有旱生和湿生植物的部分结构特征,这些现象说明了这些特征是这些植物对高寒地区低氧、低温、强辐射等自然条件长期适应的结果。7.叶表皮气孔的长宽比,气孔指数,气孔密度,叶表皮形状,垂周壁式样,叶栅栏组织层数,叶缘的形状,叶片类型,表皮毛等这些特征在种间存在着差异,同时在有些种之间又有相似性;因此,这些特征即可以作为区分种的证据,又是研究风毛菊属植物系统演化的性状指标。8.花粉近球形或长球形,极面观三裂圆形,三孔沟,外壁表面具刺状突起,刺间纹饰可分为四种类型穴状、颗粒状、网状-颗粒状和网状。花粉形态没有大的差异,但刺间表面纹饰、萌发沟的宽窄、刺的大小、分布密度和花粉大小在种间有着一定的差异,可以做为种的分类依据。9.风毛菊属中,果皮纹饰类型为:条纹型,有隔条纹型,网纹和负网纹型四种;果实表皮显微特征在同组内的种间表现出较大相似性和在不同亚属间存在一定差异性。说明果实表面显微特征可以作为划分亚属和组的分类学特征,它们在系统分类上有着重要的意义。10.利用花粉和果实的性状所作的聚类分析表明,所研究风毛菊属植物（除星状风毛菊外）大致划分为明显的4个类群,所包含的种分别隶属于风毛菊属的四亚属:雪兔子亚属、雪莲亚属、附片亚属和风毛菊亚属,与传统分类相一致,但各类群所含种类差别很大,各物种的系统位置有待进一步研究。11. 25种风毛菊属植物的染色体数目极为丰富,共有6种类型,分别是2n=24、26、28、30、32和34,核型类型也较为丰富,共有4种类型,它们是2A、3A、2B和3B,染色体长度变异范围（1.63:1-2.96:1）和核型不对称系数均较大,显示了该属植物丰富的遗传多样性,表明了风毛菊属是一个起源较早且内部分化剧烈的属。12. 25种风毛菊属植物中均末发现随体,与前人的研究结果一致。同时,我们首次首次在禾叶风毛菊中发现一对B染色体。13.风毛菊属植物对雌性投入、雄性投入和吸引结构（花瓣）的投入都随着植物个体大小增加而增加;14.随海拔的升高,18个种的小花重量并没有表现出一致的规律性,存在着种间差异;风毛菊属植物个体大小随着海拔的增高而减小;随着海拔的升高风毛菊属植物的种子并没有一致的增加或减小,与以往结果不一致。15.风毛菊属植物表现出大小依赖的性分配,大个体表现出偏雌的性分配,小个体表现为偏雄的性分配。与以往结论一致。16.植物体越大,繁殖投入越大,而其相对的繁殖分配越小。繁殖体内部也存在资源分配间的权衡,即资源分配在种子的数量和质量间存在权衡关系。17.种内花部特征和地上生物量并不随海拔的改变而改变,它们在种内是相对稳定的。18.当个体大小的因素被排除后,海拔对花柱分枝的长度和花粉的数目有着重要的和有意义的影响,花柱分枝的长度随着海拔的升高而增长,而花粉的数目则随海拔的增高而减少,同时,海拔对整个花柱的长和雄蕊的长度没有影响。在种间随着植物个体的增大,花柱分枝的长度增加,而花粉数在减少,其他的花部特征并不随个体大小的变化而变化。增长的花柱分枝能够弥补昆虫稀少和花粉数降低所带来的传粉限制,它对高山地区风毛菊属植物的有性繁殖成功有着重要的适应意义。根据我们调查,生活在青藏高原东缘的多数风毛菊属植物都具有无性繁殖方式,它保证了风毛菊属植物物种的个体数量,而花柱分枝的变长保证了风毛菊属植物的有性繁殖成功,为风毛菊属植物在该地区的进化提供了遗传变异的基础,增加了风毛菊属植物的物种多样性,使得风毛菊属植物的多数物种都成为该地区的常见种,也可能是青藏高原地区是风毛菊属植物的现代分布中心的原因之一。19.花粉受限在植物里是普遍存在的。从上述的结果,我们证实了风毛菊属植物的花粉数随着海拔的升高而减少,它说明了在高山地区另外一个可能的对花部特征进行选择的因素,这些结果支持了对花粉的竞争能够影响对花部特征的进化选择的理论和预测（Burd, 1994）。更多还原

【Abstract】 There are a lot of unique plants in Alpine Meadow of Qinghai-Tibetan Plateau,aspecific ecological system.The Saussurea plants distributed in Henduan mountainand Qinghai-Tibetan plateau and some places around them.Those distributing in theeastern of Qinghai-Tibetan plateau were studied systematicly based on themorphology,organs,cytology,encological characristics and analysing about floralgeography for systematic evolution,systematic relationship of taxonomic unit in thegenus and adaptive magnism of ecology and etc.It has important significant not onlyfor resolving systematic evolution,classification of Saussurea,but also for ultilizationof resource plants.The results are as follow:1.36 species that belong to 4 subgenera distribute in the studied region,13.64% ofthe sums of China and 62.07% of Gansu respectively.2.The three abundance of distribution existed in the region.3.4 areal type and 1 sub type were decised about the Saussurea plants in the region;temperature zone is a decisive factor of florastic characristics;The ratio ofendemic species of China and Gansu is higher.4.It may be that the region C.Asia-Himalaya is possible location of its origin.5.Type of stoma apparatus is irregular;The shape of epidermal cells aremultiangular and irregular.And their anticlinal wall are straight,arched andsinuate.The ratio of length and wide of stoma is between 1.10 and 1.54,stomadensity is between 61.35 mm^-2 and 410.43mm^-2,and stoma index is between 11%and 30% in lower epidermis.6.25 pecies plants leaves of Saussurea DC.was studied,we have discovered that onlyS.stella Maxim.is isolateral leaf and no trichome,24 plant species are bifacial leafand exist trichom.The single-layer epidermis cell,thicker cutide,well-developdepalisade tissue and aerenchyyam in palisade and spongy.Our results indicated thatthe seven kinds plants leaves is a mesophytes with part leaf structural characters ofxerophytes and liydrophytes.All of these above showed that the characteristics ofthese plants leaves are the results of adaptation to the stressful environment of the severe lack oxygen,cold climate and high solar radiation ect.7.We find these microscope characters through research are as follows:ratio betweenstoma’s length and wide,stoma density and stoma index,the shape of epidermalcells,the anticlinal wall,palisade’s layer,the type of ventilating cavity,type of limb,trichome ect.These characters are different from those of species in Saussurea,meanwhile these characters are similar to those of some species in Saussurea.Sothese characters can be used as the character indexes for differentiating species andresearching systematic evolution of Saussurea.Based on cluster analysis,we couldbe divided 25 species plant into five groups belonging to S.Subgen.Eriocoryne（DC,）Hook.f.,S.Subgen.Amphilaena（Stschegl.） Lipsch,S.Subgen.Theodorea （Cass.）Lipsch and S.Subgen.Saussurea respectively.8.The pollen morphology in this genus is highly unanimous.The pollen grains aresub-spherical or prolat with 3_colpora,3_lobate circular in polar view.The surfaceof1exine is spinulate.Some interspecific differences exist in exine ornamentation,colpus width,spinulate size,distribution density and pollen size.9.In the genus of Saussurea,the pollen grains of the genus can be divided into 4types,fovedate,granules,reticulate-granules and reticulate and the achen surfacefeature can be divided into four types,striate ornamentation,septate striateornamentation,reticulate ornamentation and negative reticulate ornamentation.Theachene ultrastructure features were constant in infraspecies.At the same time,interspecific features were similar in same section and distinctive in different ones.Therefore,it seemed to be useful to use ultrastructures in S.saussurea taxonomyboth at species and sectional level.10.Based on cluster analysis,this genus could be divided into four groups belongingto S.Subgen.Eriocoryne （DC.） Hook.f.,S.Subgen.Amphilaena （Stschegl.） Lipsch,S.Subgen.Theodorea （Cass.） Lipsch and S.Subgen.Saussurea respectively.11.Chromosome numbers of body cell for 25 species of Saussurea DC.are changedin number for different species,they are 2n=24、26、28、30、32、34;karyotypeis also abandent,they are 2A、3A、2B and 3B.The index of karyotypic asymmetryand the rang of longe of chromsome are bigger.It showed that hererity diversity ofSaussurea plants is higher and is a origin early and differentiation acutely genera. 12.No satellites have been found.But B chromosome have been found only in S.graminea of 25 species of Saussurea DC.for the fisrt time.13.The resources allocate for the female function,the male function and the attractionstructure （petal） all increase with the increase of the plant size.14.The weight of 18 species floret didn’t present accordant change trend with thehoist of elevation,the interspecific difference existed;With the hoist of elevation,the plant size decreased;15.As the plant size increased,so did the reproduction devotion,but the reproductionallocation decreased.16.There was trade-off of resources allocation between the seeds number and sizewhich indicated the existence of trade-off within the capitulum.17.The intra-specific traits are correspondingly steady.18.elevation has significant effect on length of stylar ramification,pollen number（P-values are 0.003,0.005 respectively） among species when influence ofabove-ground-biomass was removed.With increasing altitude,pollen numberdecreased and length of stylar ramification increased gradually.Increased stylarramification of plants of Saussurea with increasing altitude has importantadaptive significance of evolutionary ecology.It ensured sexsual reproductivesuccess,provided a foundation of hereditary variation and increased specificdiversity.In addition,asexsual reproduction of most species of Saussurea assuredindividual quantity.Most species of Saussurea are dominant or constructivespecies in Qinghai-Tibet plateau.19.From the results above,decreased pollen with increased altitude is another fact tochoose the flower traits in the stressful environment.更多还原