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

The report describes a system for somatic embryogenesis and direct plant re generation from the embryos of Manihot glaziovii. Somatic embryos were obta ined by culturing young leaf lobes (3-6 mm long) adjacent to the apex in Mu rashige and Skoog medium containing 18 mu M 2,4,-dichlorophenoxy acetic aci d for 20 days and then transferring them to a maturation medium with 0.5 mu M 6-benzylaminopurine. Secondary embryogenesis was induced from cotyledona ry segments of somatic embryos by using the same protocol as that for prima ry embryogenesis. For regeneration, somatic embryos were cultured in medium supplemented with 10(-4) M kinetin and 53.4% of them developed into plantl ets. Linamarin and linamarase were not detected in calli or in somatic embr yos. Linamarin content was found to be highest in leaves of regenerated pla ntlets, followed by stem and root tissues. Levels of linamarase activity we re almost the same in leaves and stem tissues and very low in roots.