2008 Volume 7 Issue 2 Pages 227-233
Morphological changes in the shoot apex of Gloriosa superba L. ‘Rose Queen’ during floral initiation and development were observed using a scanning electron microscope. The sequence of events in floral initiation and development of G. superba was similar to that in Lilium longiflorum except for morphology of perianth primordium in which both inner and outer primordia had the same shape as Tulipa gesneriana. Effects of cultivating season on flower bud formation were investigated in three genotypes ‘Misato Red’, ‘Tropical Red’ and ‘Rose Queen’. Tubers of each genotype were forced to sprout under dry conditions at 30°C for 22-24 days, and then were planted on December 2 (winter culture), on April 3 (spring culture) and on July 3 (summer culture) in a glasshouse, respectively. Most leaves were formed before planting. Floral initiation occurred when about 30 leaves were formed in any season in ‘Misato Red’ and ‘Tropical Red’. In ‘Rose Queen’, however, floral initiation occurred when 47 leaves had formed in summer culture, and at about 35 leaves in winter and spring culture. The differences in floral initiation among these genotypes seem to be caused by differences in response to temperature, especially high soil temperature which may inhibit floral initiation depending on the genotype. Once floral initiation occurred the flower bud developed rapidly in all culture season.
