Studies On Encology And Biology Of The Genus Of Saussurea (Compositae) In The East Of Qinghai-Tibetan Plateau

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.