Flow cytometric analysis of somatic embryos, shoots, and calli of the cactus Copiapoa tenuissima Ritt. forma monstruosa

Flow cytometry was used for analyzing DNA contents of nuclei isolated from in vitro grown somatic embryos, shoots and calli, as well as mammillae of in vivo grown shoots of cactus, Copiapoa tenuissima Ritt. forma monstruosa. Endoreduplication was detected in both in vitro grown somatic embryos, shoots and calli and in mammillae derived from in vivo grown shoots. However, the lowest ploidy levels ranged from 2C to 4C in somatic embryos, and reaching up to 32C for in vitro grown shoots and calli from mammillae. Whereas, ploidy levels of in vivo-derived mammillae ranged from 2C to 16C. The presence of 2,4-dichlorophenoxyacetic acid (2,4-D) in the culture medium had no influence on levels of ploidy of regenerated tissues. The mean genome size of cactus was calculated as 2C = 2.87 ± 0.05 picogram (pg).