Shoot Regeneration from the Callus of Immature Primary Leaves in Mungbean Vigna radiata(L.)Wilczek.

Abstract

Immature primary leaves of mungbean, varieties Pag-asa-1, Pag-asa-3, M79-9-82 and MG-50-10A obtained from seeds imbided for eight hours produced soft and friable calli on media containing half-strength MS inorganic salts, full- strength MS vitamins, 50 mg/l yeast extract, 1.0 approximately 2.0 mg/l L-proline, 0.1 approximately 1.0 mg/l NAA and 6-BA, and 3% sucrose. Calli from Pag-asa-1 and MG-50-10A regenerated shoots at about six weeks after transfer onto the regeneration medium which consisted of the same MS basal medium supplemented with 1.0 mg/l 6-BA. Scanning electron microscopic observations revealed that the soft and friable calli consisted of clusters of small rounded cells and loosely arranged large, elongated, or lobed cells. The clusters of small and rounded cells formed a thin cuticle layer on the surface, and then leaf initials developed from this organized group of cells during culture onto the regeneration medium. Shoots were considered to arise from the clusters of small rounded cells based on the morphological similarity of their cells.