Search Results
Abstract
Floral stalk topple, a disorder of greenhouse-forced hyacinths was investigated using ‘Pink Pearl’, a non-topple type, and ‘Blue Giant’, topple-prone type. The total floral stalk of ‘Blue Giant’ was longer than ‘Pink Pearl’. The ratio of the scape to inflorescence of ‘Pink Pearl’ was 1.0 while that of ‘Blue Giant’ was 1.8. Anatomical sections revealed that ‘Pink Pearl’ had shorter and narrower pith cells in the scape than ‘Blue Giant’. The cellular arrangement of the pith and cortex showed that, in contrast to ‘Blue Giant’, those of ‘Pink Pearl’ were tightly interwoven with very few intercellular spaces. Soil drenches of ancymidol at 2 or 4 mg/15 cm pot reduced the incidence of stem topple in ‘Blue Giant’. Ancymidol modified cell sizes and shapes and reduced the floral stalk length and scape to inflorescence ratio. It appears that floral stalk topple is related both to the anatomical structure of the cultivar and its floral stalk characteristics.
Abstract
Using a standard forcing program for early February flowering, the histogenesis of the tulip apical meristem from the vegetative state to the differentiated, immature flower was observed with the scanning and light microscopes. Root and central bulblet development were observed only with the light microscope. Total scape and root growth were measured from initiation to anthesis. The apex was vegetative on July 21, prefloral on August 1, and reached the reproductive stage “G” on August 15. The first internode was formed by August 7 and the last internode was formed just prior to reaching stage “G”. Cell division was observed in the scape from formation until after planting at 9°C. A second phase occurred in the epidermal cells, nodal regions, and vascular bundles immediately after the plants were placed in the greenhouse. It preceded the rapid rate of cell elongation in the scape. Root initiation had commenced by late July. Root growth and differentiation continued in the basal plate until mid-September, resumed during the cold treatment, and continued after the plants were placed in the green-house. The central bulblet was initiated by early August and continued to develop throughout the forcing program.