Loss of competence for glyoxysome formation during somatic embryogenesis in anise (Pimpinella anisum L.) suspension cultures

Abstract

Somatic embryogenesis in anise (Pimpinella anisum L.) suspension cultures induced by transfer to hormone-free growth medium may be synchronized by previous selection of cell aggregates with diameters between 100–240 μm. Around 80–90% of the embryoids are globular after 2–3 d, heart-shaped after 5–7 d and torpedo-shaped after 9 d. In embryogenic medium without source of carbon or with 20 mmol/l acetate differentiation and growth cease. But like in dedifferentiated cell aggregates the key enzyme activities for glyoxysomes such as isocitrate lyase and malate synthase are induced in globular (3 d old) and heart-shaped (5 d old) embryoids, but not in embryoids at day 7 or later. Similarly, in explants from anise hypocotyl glyoxysomes cannot be derepressed by such treatment. It is concluded that during differentiation of heart-shaped embryoids to torpedo forms the competence of the cells for the yet unknown inducing principle for glyoxysomes is lost.