Regeneration of Senecio x hybridus Hly. (florists'cineraria) by somatic embryogenesis

The somatic embryogenic potential of Senecio x hybridus Hyl (Florists' Cineraria) was explored. Somatic embryos were initiated on semi-solid MS basal media amended with 3 mg/l 2,4-D and 1 mg/l BA (induction medium). An inverse relationship existed between sucrose concentration in the induction medium and globular embryo formation when sucrose exceeded 3%. The first and second leaves, from 13-18 and 20 days post-sown seedlings, respectively, were more responsive explants than cotyledons from the same source and sampling times.

Somatic embryo development beyond the globular stage was greatly delayed or prevented by remaining on auxin-rich induction medium; therefore several two or three media transfer systems using either 0.5% or 1.0% AC were attempted. The two media system using (1) induction medium and a transfer to (2) MS basal medium with 1.0% AC, but without hormones, caused explant death or decline by 28 days post-inoculation to induction medium. The three media transfer system using (1) induction medium, (2) MS basal medium without hormones, supplemented with 0.5% AC for three days followed by a transfer to (3) MS basal medium without hormones and AC produced mature somatic embryos by 28 days post-inoculation to induction medium; however, embryos germinated precociously. Occasionally, explants that were not transferred from the initial induction medium (controls) developed mature embryos that did not germinate precociously after two-four months. Somatic embryos converted to plants and were grown to maturity: however, most plants were multi-stemmed. Histological examination of mature somatic embryos produced verification of embryo anatomy.