Cold Storage Period of Bulbs Influences Their Sugar Contents and Post-Storage Growth and Flowering in Lilium Oriental Hybrids

This study was carried out to investigate the changes in internal shoot growth, total and reducing sugar content, plant growth, and flowering characteristics after cold-stored bulbs of Lilium Oriental Hybrids are planted. Bulbs of Lilium Oriental Hybrids ‘Le Reve’, ‘Sorbonne’, and ‘Siberia’ were harvested at the end of November, cleaned, treated with fungicides, conditioned for 30 days at 4 °C, and cold-stored for 30 to 120 days at 0 °C. Plant height, fresh and dry weights, leaf numbers and area, chlorophyll content (SPAD index), days to flowering, number of flower buds, and flower diameter were measured when the cut flowers were harvested. In all cultivars, the shoot lengths in the bulbs increased as the storage period increased. As the storage period was extended, the fructose and glucose contents increased, whereas sucrose content decreased. The total sugar content increased during the early storage period and decreased subsequently. Plant height, fresh and dry weights of cut flowers showed a decreasing trend as the storage period increased. Flower diameter generally decreased with increasing storage period but varied among cultivars. These results indicated that more storage carbohydrates in bulbs were consumed as the storage period increased, and thus, the subsequent plant growth and flowering were negatively affected.

Pollen Ultra-Morphology and Pollen Viability Test of Lilium Oriental Hybrids

Ultra-morphology and pollen viability assessment are essential to understand evolutionary ecology and sterility problem, and to design hybridization program in cross-breeding. The pollen ultra-morphology of two Lilium Oriental hybrid cultivars, „Sorbonne‟ and „Siberia‟ were observed using scanning electron microscope. And the pollen germination condition in vitro and four dye tests methods for pollen viability were determined. The results showed that pollens of two Lilium Oriental hybrid cultivars were much alike in ultra-morphology with ellipsoidal shape, reticulate surface decoration and single germination ditch, indicating a close genetic relationship between two cultivars. The suitable medium for pollen germination of two cultivars composed of 10% sucrose, 0.1% boric acid and 0.5% agar. The pollen germination percent reached the highest at 25oC. Although I2-KI stain, TTC stain and peroxidase precipitation methods were not suitable for lily pollen viability test, the pollen viability tested by acetocarmine method were close to that by in vitro pollen germination at suitable condition, which suggested acetocarmine stain can be as a quick test method for pollen viability of Lilium Oriental hybrids. © 2018 Friends Science Publishers