Relationship between annual cycle and floral development of threeAlliumspecies from subgenusMelanocrommyum

Scanning electron microscopy (SEM) was used to study the monocarpic shoot development and florogenesis of three species from the genusAllium, in connection with their annual cycle. Initiation of leaf primordia in the Central Asian species,A. karatavienseandA. altissimum, begins with the renewal bulb during the flowering stage of the mother plant. After differentiation of leaf primordia, the apical meristem of these species remains inactive for 6–10 weeks. The meristem begins florogenesis in August, during the ‘dormancy’ stage of the mother plant. InA. rothiifrom the Negev desert, the apical meristem remains inactive for 12–15 weeks after flowering of the mother plant, leaf primordia form in July–October and the meristem then becomes reproductive immediately. Since the inflorescences of all the species studied consist of regularly arranged cymes, many stages of floral development can be observed simultaneously