Bourgeonnement in vitro a partir d'épiderme séparé de feuille de Bryophyllum Daigremontianum (Crassulacées)

Abstract

The lower epidermis from leaves of Bryophyllum Daigremontianum Berger has been mechanically separated and cultured in liquid or solid medium; cytokinin and auxin in combination have been necessary to obtain a lamellar callus, with the Murashige and Skoog's macroelements being more efficient than White's, Knop's, or Lin and Staba's. Numerous buds have been initiated after 3 or 4 weeks, especially with naphthaleneacetic acid (1 mg/litre) in combination with 6-benzylaminopurine (0.2 mg/litre). The best results for bud formation have been obtained with the epidermis of the first and second well developed leaves. The buds, rooted in vitro, developed into normal plants. The histological study has showed that the callus was originated only from the banal epidermal cells. The stomatic cells have not been activated and died. The other tissues of the leaf have never produced any bud in the same culture conditions; then, as for other species, the epidermis has a greater ability to initiate a budding programme.