Somatic embryogenesis from mature leaves of rose (Rosa sp.)

Several plant growth regulators (0.3–53.3 μm 6-benzyladenine, 2,4-dichlorophenoxyacetic acid, gibberellic acid, 3-indoleacetic acid, p-chlorophenoxyacetic acid, kinetin and α-naphthylacetic acid), alone or in combination, and culture conditions were tested for their capacity to induce somatic embryogenesis from mature leaf and stem explants of rose (Rosa sp.) of four commercial rose cultivars (Baccara, Mercedes, Ronto and Soraya). Somatic embryos were only induced from mature leaf explants derived from Soraya on Murashige and Skoog (MS) medium supplemented with 53.5 μmp-chlorophenoxyacetic acid and 4.6 μm kinetin, although satisfactory callus induction rates were obtained from all cultivars. After subculturing on the same medium, embryos at various developmental stages (globular, heart and torpedo shaped) were transferred for maturation onto a MS medium supplemented with 5.2 μm 6-benzyladenine and 5.7 μm 3-indoleacetic acid. Germination of mature embryos took place after subculturing them onto medium of the same composition. Plantlets regenerated from embryos and bearing three to four leaves were transferred to a greenhouse.