Factors affecting in vitro shoot formation from vegetative shoot apices of apple and relationship between organogenic response and cytokinin localisation
Faculty of Sciences. Biology
Plant biosystems / SocietÓ botanica italiana. - Firenze
COST 8 22 Working Group Meeting, OCT, 1999, ANCONA, ITALY
, p. 95-100
University of Antwerp
The effects of macro- and micro-elements, benzyladenine (BA) concentration, and the period of auxin application on adventitious shoot formation from callus originating from vegetative shoot apices were tested on dapple (Malus domestica Borkh) rootstock Jork 9, The putative relationship between organogenic response and cytokinin localisation was also studied by, an immunolocalisation technique for in situ determination of free cytokinins, The Use Of MS (MURASHIGE & SKOOG, 1962) salts in the medium instead of those of LP (QUOIRIN & LEPOIVRE, 1977) had a strong positive effect both on shoot formation rate and on the number of shoots produced. The highest organogenic response from callus was induced using 17.8 muM BA in the presence of 2.7 muM NAA and by maintaining the explants for 20 days in darkness, then transferring them to fresh auxin-free medium and to the light. The in situ localisation studies, performed Using antibodies with a marked specificity against zeatin and isopentenyladenine, revealed changes in the localisation of free zeatin in the tissues during the shoot-forming process, in particular during the active cell division phase leading to callus formation, and in the initial phase of bud formation, Changes in zeatin distribution in the tissues of the vegetative shoot apex during shoot formation may indicate a role for this cytokinin free base in cell differentiation and organogenesis.