Somatic embryogenesis and plant regeneration from hypocotyl and leaf explants of Brassica oleracea var. botrytis (cauliflower)

Abstract

We investigated direct and indirect formation of somatic embryogenesis in Brassica oleracea var. botrytis (cauliflower), a very important vegetable crop worldwide. Direct somatic embryogenesis, which is rather rare, was achieved in culture of 2-week-old hypocotyl explants of Brassica oleracea var. botrytis on MS medium supplemented with 1.0 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.5; 1.0; and 1.5 mg/l kinetin. Initial induction of embryogenic callus was achieved on MS supplemented with very low concentrations of 2,4-D (0.05 mg/l and 0.1 mg/l). Indirect somatic embryogenesis from leaf sections was obtained on MS supplemented with 0.05 or 0.1 mg/l 2,4-D. We examined various stages of somatic embryos (globular, heart, torpedo, cotyledonary). More embryos per explant were produced through the indirect pathway (23-25) than through the direct pathway (14-19). The number of embryos produced was high. There is a potential for recurrent, repeated or secondary somatic embryogenesis, possibly an unlimited source for mass propagation and ideal for synthetic seed production in this species. Plant regeneration was achieved on half-strength MS medium without any hormones. © Polish Academy of Sciences and Jagiellonian University, Cracow 2011.