Studies On The Chromosome Ploidy Level And Karyotype Of Miscanthus

The species of Miscanthus are tall perennial C₄-type grasses in gramineae,which has a high potential as a kind of biomass resources and has attracted wide interests in recent years.In this study,the chromosome ploidy levels and karyotypes of M.sinensis,M.floridulus, T.sacchariflora and M.lutarioriparia in the China Mainland had been analyzed by the chromosome squashing method as well as the flow cytometry.The main results are as follows:1.The parameters of chromosome squashing method for Miscanthus species had been optimized,for example the reagent and time for pretreatment or the reagent and time for dissociation and a technique of chromosome preparation for Miscanthus species had been preliminarily established.The root tips were pretreated in the solution of 0.2% colchicin and 0.002 mol/L 8-hydroxyquinoline under the room temperature for 2 h,and then fixed in Carnoy's liquid for 20 h at 4?; After fixation,the root tips were treated in 1 mol/L hydrochloric acid for 15 min at 60?and then processed with 2%cellulase for 1h at 28?to dissociate;Finally,after fixed for the second time,the root tips were produced into chromosome slides and stained with the improved carbol fuchsin solution. 2.The karyotypes of Miscanthus populations,including 10 populations of M.sisensis,4 populations of M.floridulus,1 populations of T. sacchariflora and 1 populations of M.lutarioriparia were analyzed.In M.sisensis,the karyotype formula of populations from Chenggu Shaanxi,Zhuhai Guangdong,Baise.Guangxi,Xingshan Hubei, Qingzhen Guizhou,Menghai Yunnan and Leshan Sichuan was 2n=2x=38=30m+8sm,and 2n=3x=57=45m+12sm for population from Fengxian Shaanxi,2n=2x=38=32m+6sm for population from Changsha Hunan,2n=2x=38=28m+10sm for population from Wuzhishan Hainan. The karyotype formula of M.floridulus population was 2n=2x=38=30m+8sm,and 2n=2x=38=28m+10sm for T.sacchariflora population as well as for M.lutarioriparia population.3.On the basis of karyotype analysis,the flow cytometry was used to measure the chromosome ploidy levels of Miscanthus species in China mainland.The results showed that in the populations,comprising of 96 M.sisensis,51 M.floridulus,15 M.sacchariflora and 5 M. lutarioriparia,most were diploids except for a triploid found in M. sisensis and T.sacchariflora respectively,and a tetraploid population in M.lutarioriparia.There was a little difference in the DNA content among different species as well as different populations in the same species.