Comparison of chromosome spreading methods and karyotype of Passiflora edulis Sims

Effects of different pretreatments methods,dissociation,enzymolysis time and slide making on the metaphase cells,chromosome contraction and dispersion degree of P. edulis Sims were compared.The best metaphase cells were prepared after the pretreatment with 8-Hydroxyquinoline for 2.5 h at room temperature and the subsequent enzyme digestion by a mixture containing 2% cellulase and 0.5% pectinase for 70 min at 37 ℃.The chromosomes dispersed well with clean background and centromeric dots and satellite were clear.The karyotype formula of P. edulis Sims was 2n=2x=18=14m(2sat)+4sm,belonging to 2A type,and a pair of satellites were located on the forth pair chromosomes.