Study on tuber formation, development and storage in cut flower production system of Gloriosa superba L

I. Controle of tuber development by controle of node numbers of flower bud differentiation. I-1. Morphological changes in the shoot apex during floral initiation and development. 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. I-2. Genotypic differences in floral initiation and development. 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 30degC 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. I-3. Effects of soil temperature and temperature to enhance sprouting on node number of flower bud differentiation. Effects of temperature on node numbers of flower bud differentiation of Gloriosa superba L. were investigated using three genotypes, 'Misato Red', 'Tropical Red' and 'Rose Queen'. Tubers of each genotype were kept at 30degC for 23 days to enhance sprouting, and then were planted in a greenhouse with soil temperature controlled at 19.1+-0.6degC or 31.6+-1.0degC. Flower buds initiated at the same node order under both temperature conditions in 'Misato Red' and 'Tropical Red', whereas 'Rose Queen' produced larger numbers of leaves at a higher soil temperature. When tubers were kept at 15 to 40degC for 56 days under dry conditions, flower initiation occurred at 30degC or below in 'Misato Red' and at 35degC or below in 'Tropical Red' during th