FLOWER BIOLOGY IN LILIUM: ACHIEVEMENTS AND RESEARCH CHALLENGES
Flowering involves a variety of molecular, physiological, and biochemical mechanisms regulating the proper timing and correct development of the reproductive organs. Sensing and integration of the external cues (temperature, photoperiod, irradiance, and stress) by the plant are necessary for the optimal timing of flowering during the year, for synchronized flowering within a population, and for successful seed development. Therefore, horticultural manipulations aimed at directing flowering to specific periods usually make use of these cues. In geophytes, florogenesis can be divided into several consecutive steps: induction, initiation, differentiation (organogenesis), maturation and growth of floral organs, anthesis and senescence. A major distinction can be made between the geophytes in which flower initiation takes place within the bulb during the dormancy period prior to growth (Tulip type), and those in which flowering is initiated during active growth, following the development of several leaves (Lily type). The commercial cultivars of L. longiflorum require low temperatures and a long photoperiod for florogenesis. Although breeding of commercially important hybrids has great commercial value, only limited data are available on molecular regulation of flowering. To date, two basic strategies have been used to isolate genes involved in florogenesis. The first is based on sequence homology between species. Numerous homologues of genes from model plants have recently been isolated from geophytes. The second approach is broader and involves the determination of a large number of genes, using cDNA libraries and isolation of the genes expressed in specific tissue locations or physiological states. Recently, next generation sequencing (NGS) technology has been used to sequence the transcriptomes (RNA-seq) of lily cultivars. Investigations in the coming decade are expected to improve our understanding of this process, thus contributing to the development of breeding techniques and the production of new hybrids.
Kamenetsky, R. (2014). FLOWER BIOLOGY IN LILIUM: ACHIEVEMENTS AND RESEARCH CHALLENGES. Acta Hortic. 1027, 65-74
florogenesis, flowering, environmental regulation