Pollen Morphology And Taxonmic Significance In Changbaishan Area,China

Palynology can be divided into two directions,one is the modern palynology,another is paleopalynology.It mainly studies the spores and pollen,according to the study of the pollen morphology can help solve the problems in the plant taxonomy,stratigraphic identification of strata correlation,research on the vegetation is mainly used in the paleovegetation ancient climate and ancient ecological aspects.Changbai Mountain has large tracts of virgin forest intact,provides a good material for the study of Botany and ecology.We were collected flowering plants of the Changbai Mountain nature reserve for several times.By using light microscope(LM)and scanning electron microscope(SEM)to study on the pollen morphology of flowering plants in Changbai Mountain area,the pollen morphology and its characteristics were statistically analyzed:In this paper,pollen morphology of 225 species of flowering plants(including 13 varieties and two subspecies)from the Changbaishan area are described and illustrated under light microscope and scanning electron microscope,which belong to 59 families and 155 genera.The differences of pollen morphology in different plant species were mainly in shape,size,apertures and exine ornamentation.There were significant differences in pollen morphology among different families,and the pollen morphology of one family was mainly different in size,apertures and ornamentation,but the pollen morphology in the same genus was similar,mostly,they were different only in ornamentation.The results show that pollen grains were nearly subspheroidal(35.1%),subprolate(28.9%),prolate(13.3%)or spheroidal(8.9%),respectively has 79 species,65 species,30 species and 20species,and also contain subolate(3.1%),oblate(3.1%),pererect(1.8%),peroblate(1.2%),tetrahedral tetrads(2.2%),bottle-like pollen(1.2%),pollinium(0.4%)and cocoon shape pollen(0.4%),etc.The maximum pollen grain is Malva ohileviensis Downar in Bull.,107.4(82.5?118.0)?m;and the minimum pollen grain is Astilbe chinensis(Maxim.)Franch.et Savat.,13.9(12.5-15.8)×11.1(10.3?14.0)?m;P/E value of Coelopleurum saxatile(Turcz.)Drude was the maximum(average 2.15,up to 2.35),and the smallest for the Balsaminaceae,pollen grains are ultra oblate;Aperture type is mainly 3-colpate and 3-colporate with a percentage of 41.3%and 22.2%,and also contains single-apeture,6-colpate,4-apeture,single-colpate,3(-4)colporate,4-colpate,etc.The outer wall thickness difference of different genera is large,the most thick wall is Polygonum thunbergii Sieb.et Zucc.(wall thickness 8 ?m),the thinest is Brachybotrys paridiformis Maxim.ex Oliv.(wall thickness of 0.5 ?m).Under the light microscope,there are six types of extine ornamentation,including reticulate(39.6%),spinulose(15.1%),granulate(16.9%),coarsely reticulate(15.6%),striate(4.4%)and striate-perforate(3.1%),others also have cellular ornamentation and smooth ornamentation.Under the scanning electron microscope are mainly coarse reticulate exine ornamentation,finely reticulate,granular,massive,spiny,wrinkled,brain striated streak-perforation,perforation,wrinkle-particles block hole perforation,perforation,perforation,spiny-messy rod stripes 12 types.Pollen morphology in different genera of the same family,different species of the same genera,and different regions of the same species were also discussed in this study.In addition,the pollen morphology of the genus Salix were classified and discussed.According to the types of aperture,Salix were divided into 4 types,respectively:3-colpate type,3-colporoidate type,3-colp(oroid)ate type and syncolpate type,and a key of Salix taxa were list based on the characteristics of exine ornamentation.We also studied the paleoenvironmental significance of some pollen assemblages,when a large numbers of Salix,Ulmaceae,Betulaceae and Fagaceae pollen were appeared in the strata,it indicated for broad-leaved forest,where the climate is warm and humid climate;When Caryophyllaceae,Polygonaceae,Lythraceae,Ranunculaceae,Cruciferae,Leguminosae,Rosaceae,Labiatae,Umbelliferae,Compositae,Liliaceae,Urticaceae,Rubiaceae etc.pollen were appeared in the strata,it indicated for mixed coniferous broad leaved forest or broad-leaved forest,indicating the type of climate is warm and moist climate;When lots of Ericaceae pollen appeared in the strata,it indicated that the cold environment,and the vegetation types were alpine meadows,tundra or coniferous forest.Observation and description on pollen morphological characteristics of these species are important keys to the identification of fossil pollen grains of related taxa,and also could provide some basic data for pollen researches of the Quaternary Strata.