2021 Volume 86 Issue 1 Pages 21-28
Artificial tetraploid and octaploid strains were induced from the wild species of Drosera rotundifolia (2n=2x=20) and D. anglica (2n=4x=40), respectively. The optimal condition of colchicine-treatments for polyploid inductions was determined first. A flow cytometry (FCM) analysis showed that the highest mixoploid score of D. rotundifolia was 20% in the treatment of 0.3% for 2 days (d), or 0.5% for 3 d, while the highest mixoploid score of D. anglica was 20% in the treatment of 0.5% for 2 d. Next, to remove chimeric cells, adventitious bud inductions were carried out using the FCM-selected individuals in both species. One strain from a total of 360 colchicine-treated leaf explants in each species had pure chromosome-double numbers of 2n=40 (tetraploid) in D. rotundifolia and 2n=80 (octaploid) in D. anglica. In both species, the guard cell sizes of the chromosome-doubled strains were larger than those of the wild types. The leaves of the chromosome-doubled strains of D. rotundifolia were larger than those of the wild diploid D. rotundifolia, while the leaves of the chromosome-doubled strains of D. anglica were smaller than those of the wild tetraploid D. anglica.
