Comparative karyotype analysis of six native <i>Passiflora</i> species (Passifloraceae) from SW China

Abstract

Chromosomes squashes could be obtained by using the conventional tableting method and the karyotypes were analyzed. The results showed that all six species of passion flower were diploid and the chromosome number was 2n=12. The karyotype formula of P. menghaiensis was 2n=2x=12=8m+2sm+2sm(sat), P. xishuangbannaensis was 2n=2x=12=8m+4sm, P. siamica was 2n=2x=12=10m+2sm, P. altebilobata was 2n=2x=12=10m+2sm, P. henryi was 2n=2x=12=8m+4sm, P. papilio was 2n=2x=12=12m. The karyotypes of all six species are reported for the first time. This study provides comprehensive cytological data for the conservation and genetic study of Passiflora in Asia. The evolutionary relationships between the six species were discussed at the cytological level and compared with published classifications based on morphological and molecular data.