Biosystematics Of Three Populations Of Christolea Crassifolia And Palynology Of Partial Genera And Species In Brassicaceae

The karyotype,pollen morphology,stoma traits of epidermis,and exterior appearance of Christolea crassifolia in three different populations of the Parmirs have been investigated completely by the principles and methods of populations in this paper.Pollen morphology of 13 species(including Ch.crassifolia in three populations) belonging to 8 genera of 4 tribes(Arabideae,Matthioleae,Hesperideae,Sisymbrieae) were studied.The results indicated that:(1) Three populations of Ch.crassifolia①The karyotype formula of Kalasu population is:K=2n=2x=14=10m+2sm(SAT)+2sm,the karyotype formula of Bulunkou population is:K=2n=2x=14=6m+2m(SAT)+6sm,the karyotype formula of Waqia population is:K=2n=2x=14=12m+2sm(SAT).The karyotypes of the 3 populations are all Stebbins's 1A type,and the asymmetric coefficients are Kalasu's 60.30%,Bulunkou's 60.86%,Waqia's 60.17%.②The observations of scanning electron microscope showed that the pollens of the three poulations are all three-colpate,with reticulate ornamentation and the polar views are all three-lobed circle,but there are significantly differences in the shape of pollen,the diameter of areole and the width of murus.③The shape of upper and lower epidermis cells of Ch.crassifolia in three populations are all polygons with 3～6 sides,the anticlinal walls are straight,and stomatic distributed in upper and lower epidermis.The stomatal density of upper epidermis is denser than that of lower epidermis in Kalasu population comparing with Bulunkou and Waqia populations.The stomatal apparatus of three populations are all irregular types,and the guard cells are all kidney-shaped and there are no subsidiary cell.④The UPGMA dendrogram using 32 traits for 3 populations of Ch.Crassifolia shows that,Kalasu population formed one group alone,Bulunkou and Waqia populations formed another group.Variance analysis of 32 traits among 3 populations of Ch.crassifolia indicates that 25 traits have evident difference, and seven traits have no evident difference. ⑤The chromosome numbers,asymmetric coefficient,the type of germinal aperture,polar view,exine sculpture,the shape of upper and lower epidermis cells,anticlinal wall,the distribution of stomatal,the type of stomatal apparatus,the shape of guard cells,leaf shape index,petal length,petal width,filament length of Ch.Crassifolia have good stability.(2) The pollen morphologyThe pollen morphology of 13 species belonging to 8 genera of 4 tribes is very similar,their shape varies from prolate to perprolate with reticulate ornamentation,the pollen grains are most tricolpate(rarely teracolpate).Five pollen types can be distinguished based on the shape of pollen grains,the size of the areole and the number of the aperture:①Pollen grains three-colpate,prolate,with reticulate ornamentation;②Pollen grains three-colpate,perprolate,with reticulate ornamentation;③Pollen grains three-colpate, prolate,with microreticulate ornamentation;④Pollen grains three-colpate,perprolate,with microreticulate ornamentation;⑤Pollen grains three-colpate or four-colpate,prolate,with reticulate ornamentation.