Micropropagation of Senecio Macrophyllus M. Bieb

Abstract

Ten-day-old Senecio macrophyllus M. Bieb. seedlings were the experimental material. The seeds were obtained from the Botanical Garden of Maria Curie- Sklodowska University (Lublin, Poland). They were surface-sterilized with 70% (v/v) ethanol for 30 s and then in 20% (v/v) solution of NaOCl (Domestos This is the first protocol for in vitro micropropagation of Senecio macrophyllus. Shoot tips and fragments of the cotyledon, hypocotyls and roots were isolated from 10-day-old sterile seedlings. The morphological response was tested on MS medium supplemented with different types of cytokinins: BA (2.2 μM, 4.4 μM or 13.3 μM), KN (4.7 μM or 13.9 μM) and ZEA (4.6 μM or 13,7 μM) in combination with 0.54 μM NAA or 0.27 μM NAA (with 2.2 μM BA only), but only shoot tips were capable of shoot organogenesis. Shoot proliferation was highest for explants cultured on MS medium supplemented with 4.4 μM BA in combination with 0.54 μM NAA. The shoots formed were then multiplied on the same medium. Rooting was achieved on full- and half-strength MS medium without auxin, but shoots cultured on medium BA-supplemented began inducing roots a week later than shoots obtained on media with other types of cytokinins. Well-rooted plantlets were transferred to ex vitro conditions. The survival rate of rooted plants was 100% for plants cultured in a mixture of vermiculite and sand, and 92% for those plant- ed in soil after 4 weeks of acclimatization. In the first year the plants grew intensively under field conditions and were able to develop a leaf rosette. In the second year the plants were able to flower and produce viable seeds.