Growth characteristics and chromosomal behavior of cell suspension lines established from pollen callus of peony.

Abstract

Six cell suspension lines (Kp9, Kp10, Kp20, Kp42, Tp1 and Tp4) established from pollen calli of two Paeonia cultivars have been studied with special reference to their growth characteristics and chromosomal behavior. They reached stationary phase after about 14 days of subculture showing about a 6- to 10-fold increase in packed cell volume, regardless of their ploidy levels. The mitotic index in each line showed a maximum value of between 6-8% after about 5 days of subculture.Haploid cell lines of Kp9, Kp20 and Tp1 maintained haploid chromosome numbers (n=5) at high values (more than 90%) even after 620 days of subculture. However, the Kp42 line changed from the original haploid to the mixoploid by an increase in diploid cells during subculture. The diploid Kp10 and the mixoploid Tp4 lines retained their characteristic chromosome number throughout subculture. In the mixoploid Kp42 and the Tp4 lines, the cells having 5 or 10 diplochromosomes resulting from endoreduplication in a haploid or a diploid nucleus were occasionally found.