Rapid Identification Of Chromosome Ploidy In Hordeum Bulbosum And The Initial Screening Of Salt Tolerance

This study used flow cytometry to estimate the DNA content in the wild barley nucleus.This method involves the preparation of an aqueous suspension of intact nuclei using DNA propidium iodide(PI).Nuclei are classified according to their relative fluorescence intensity or DNA content.Due to the ease and speed of sample preparation and analysis,DNA flow cytometry has become a common method for identifying plant ploidy,aneuploidy,cell cycle analysis,multiplicity assessment,reproductive pathways and estimating genomic size.The estimated nucleic acid content of this experiment is the ratio between the nuclear fluorescence intensity of the sample stained with propidium iodide(PI)and the external standard.The known tetraploid wild barley variety(PI 320196)was used as an external standard,and its fluorescence value was located at 400,and other unknown ploidy wild barley varieties were identified.After screening 8 nuclear separation buffer solutions,the Galbraith nuclear separation buffer,which is most suitable for wild barley flow cytometry to identify ploidy,was selected.Among the 52 wild barley varieties,two diploid wild barley varieties and 50 tetraploid wild barley varieties were identified.Furthermore,the changes of proline content in barley leaves under different salt stress were analyzed by osmotic stress in different regions.The proline correlation of barley under high salt stress was analyzed by RT-PCR.The expression of synthetic(P5CS)and decomposition(PDH)genes was screened out.In the face of osmotic stress,the proline-synthesis-related gene P5CS responded positively,and the proline accumulation rate was faster.When osmotic stress,these three varieties also had higher initial proline concentration than other varieties,and had better tolerance to osmotic stress.