Plant regeneration from mesophyll protoplasts of Lactuca perennis

Abstract

Cultured protoplasts of young, unexpanded leaves of the wild lettuce, Lactuca perennis, divided to produce cell colonies in an agarose-solidified, modified MS medium with reduced levels of inorganic salts, together with 2,4-D, NAA and zeatin at 0.2, 0.1 and 0.5 mg 1-1 respectively. Organogenesis followed the initial transfer of protoplastderived colonies to modified MS medium with 2,4-D, NAA and zeatin (0.1, 1.0 and 0.2 mg 1-l respectively) and then to full-strength MS medium with 6-BA and NAA (0.4 and 0.05 mg 1-l). Shoots were rooted on agar-solidified MS medium lacking growth regulators. Regenerated shoots were established ex vitro, 21 weeks after protoplast isolation.