Flowering physiology and flower development of Lilium longiflorum (Easter lily)

Over the years, it has generally been accepted that Lilium longiflorum has an obligatory requirement for vernalization and that a long-day (LD) regime hastens flowering. New findings revealed that bulb size affects its flowering pathway. The aim of this study was to further explore the effect of bulb size, vernalization and photoperiod on L. longiflorum flower induction and development. Vernalization and photoperiod treatments were applied on different bulb sizes, and a system of constant ambient temperature of 25°C, above vernalization spectrum, to avoid cold-dependent floral induction during plant growth, was used. Vernalization and LD hastened anthesis in all bulbs. Small, non-vernalized bulbs that flowered under LD conditions showed the fastest flower development (time from visible bud to anthesis). Sibling bulblets from the same mother plant, which were sorted by size and planted without cold treatment under LD conditions, flowered according to their size.