Somatic embryogenesis, plant regeneration and cyanogenesis in Manihot glaziovii Muell. Arg. (ceara rubber).

The report describes a system for somatic embryogenesis and direct plant regeneration from the embryos of Manihot glaziovii. Somatic embryos were obtained by culturing young leaf lobes (3-6 mm long) adjacent to the apex in Murashige and Skoog medium containing 18 μM 2,4-dichlorophenoxy acetic acid for 20 days and then transferring them to a maturation medium with 0.5 μM 6-benzylaminopurine. Secondary embryogenesis was induced from cotyledonary segments of somatic embryos by using the same protocol as that for primary embryogenesis. For regeneration, somatic embryos were cultured in medium supplemented with 10 M kinetin and 53.4% of them developed into plantlets. Linamarin and linamarase were not detected in calli or in somatic embryos. Linamarin content was found to be highest in leaves of regenerated plantlets, followed by stem and root tissues. Levels of linamarase activity were almost the same in leaves and stem tissues and very low in roots.