Bull. Spec. CORESTA Congress, Guangzhou 1988, p. 124, PP-6
In vitro flower formation using the thin cell layer technique
Istituto Sperimentale per il Tabacco, Scafati, Italy
It is well known from literature that a subepidermal layer of Nicotiana tabacum can differentiate de novo several organs (callus, shoots, roots, floral buds) in certain cultural conditions. Such amorphogenetic program is influenced by numerous factors, and in particular, as far as hormones are concerned, by the equilibrium auxins-cytokinins present in the culture medium. In the present research we have taken into account the effects of auxins and cytokinins, considered both independently and in combination, the effect of pH of the medium, the physiological state of inflorescence and the level at which the explants were drawn. The best results to produce floral buds in vitro were obtained with Kin 9 x 10-7 M in combination with IAA 4.5 x 10-6 M in the range of pH between 5 and 6 on explants from secondary, tertiary axes, and floral pedicel when the inflorescence shows floral buds, flower in anthesis, and capsules with ripening seeds. Our results, besides confirming a n increment in regenerating capacity from the base of the stem to the apex of the inflorescence, clearly show a tendency to produce flower which increases from primary to floral axes with a clear prevalence of pedunculate flowers as opposed to sessile ones. In addition, the latter type proved to be sterile where as the pedicel flowers normally produced fertile pollen.