COMPARATIVE PERFORMANCE OF IN VITRO AND EX VITRO SHOOT AND ROOT FORMATION IN THE PLANT FAMILIES ROSACEAE AND ERICACEAE

Shoot and root formation in Arctostaphylos and Spiraea were compared in in vitro and ex vitro conditions. In vitro cultures were on Anderson's medium with isopententyladenine (Arctostaphylos) or Linsmaier and Skoog medium containing benzyladenine (Spiraea); ex vitro shoot proliferation was achieved using cytokinin sprays. Some cultures contained indolebutyric acid instead of cytokinin and ex vitro rooting was also conducted for shoots which had been produced in vitro. Additionally, rooting experiments were conducted for shoots produced by cytokinin spray treatment and for cuttings taken from normally raised plants. In both Arctostaphylos and Spiraea, the number of shoots formed in four weeks from one shoot in vitro was similar to the number formed on one intact one-year-old plant after cytokinin treatment. There was no significant difference in root number on in vitro produced shoots between shoots rooted in vitro and ex vitro, but shoots from cytokinin sprayed plants and stem cuttings rooted better than in vitro produced shoots. IBA significantly increased rate of rooting in both types of cuttings.