Variation of nuclear DNA content during somatic embryogenesis and plant regeneration of Coffea arabica L. using cytophotometry

Abstract

Cytophotometric analysis of nuclear DNA was carried out in leaves of Coffea arabica L. plants grown in vitro. They were maintained for more than 1 year on MS media containing 0.53 μM NAA, and 2.32 μM kinetin, and embryogenic calli and somatic embryos were derived from them. Four suspension cultures of C. arabica differing in their embryogenic potential were also studied. In in vitro leaves used as primary explants many nuclei gave values that were hypoaneuploid, yet the somatic embryos derived from them consisted predominantly of diploid cells. As primary explants were shifted to conditioning medium (MS medium added with 0.53 μM NAA and 2.32 μM kinetin) and then to induction medium (to obtain embryogenic calli; Yasuda medium supplemented with 5 μM BAP), the frequency of hypoaneuploid values dropped. An analysis of four suspension cultures did not reveal any relationship between the cytogenetic state of cell strains and their morphogenetic potential. Of four suspensions, cultures having similar frequencies of diploid cells (60–82%), only one was capable of embryogenesis.