Isoperoxidases as markers of somatic embryogenesis in carrot cell suspension cultures

Abstract

Growth, peroxidase activity and isoperoxidase pattern were studied during the growth cycle of 3 cell suspension lines of carrot (Daucus carota L.), an embryogenic, a non‐embryogenic and a habituated cell line. Isoelectric focusing of extracted proteins on agarose gels revealed the isoperoxidase pattern of the embryogenic line to include, among other differences, an isoperoxidase with a pl of pH 7.0 when grown under conditions stimulating embryogenesis. This isoperoxidase (P7.0: EC 1.11.1.7) was present between days 2 and 6 after subculturing, and this period correlates well with the early stages of somatic embryogenesis. This isoenzyme showed very low activity in the non‐embryogenic and habituated cell suspension lines as well as in the embryogenic cell line in the presence of Daucus carota, 2,4–dichlorophenoxyacetic acid. P7.0 could probably be used as a biochemical marker of somatic embryogenesis.