Morpho-Histological Analysis of Direct Shoot Organogenesis Induced in Flower Buds Cultures of <i>Allium altissimum</i>

The present work gives a detailed study of in vitro shoot organogenesis of the ornamental onion A. altissimum Regel from the buds of the middle layer of the inflorescences. The course of morphogenesis was examined by light and scanning electron microscopy. Histological observation revealed that during 3 - 5 days of culture on the BDS medium supplemented with 2.0 mg·L-1 of BA and 2.0 mg·L-1 of NAA the epidermal cells of the stamen filament in the area of its fusion with the tepal became competent and dedifferentiated. Originally the organogenesis involved several initial epidermal cells. The formation of meristematic centers was observed from day 3 to day 14. The apical shoot meristems and leaf primordia in a roller shape formed from day 14 to day 28 of culture on the same media. The further development of vegetative shoots and formation of the bulblets were observed when the explants were stimulated by triapenthenol (2.0 mg·L-1).