Karyotype analysis of Phasolosma esculenta

The samples of Phasolosma esculenta were raised for 24 h in 0.04% colchicines solution. Its celomic cells were extracted and treated with lower osmotic pressure, fixed, dropped, air-drying and stained. Photographs of well-spread metaphases were examined and taken with a photomicroscope. The chromosome types were categorized according to Levan. It was found that the basic number of chromosome of P. esculenta was x=10, 2n=2x=20 and the karyotype formula was 2n=2x=4m+ 10sm+6st, NF=40. The chromosome pair numbers 1, 2, 5, 6, 7 were submetacentric, the chromosome pairs numbers 3, 10 were metacentric, other chromosome pairs were subtelocentric. The total length of genome was 40.136 μm. In all chromosomes, the longest was 5.129 μm, the shortest was 3.092 μm and the average length was 4.014 μm. Arm ratio was in range of 1.483-3.566.