Changes in pigment content and surface micro-morphology of in cut carnation flower petals under high-temperature conditions.

摘要

Senescence of carnation petals progresses gradually, even when climacteric ethylene production is blocked. The most distinct visible changes in the later stages of petal senescence are a fading of flower colour and a change in appearance ("freshness"). Cut carnation cv. Excerea flowers treated with silver thiosulphate were kept in vase solutions with or without 1% (w/v) sucrose under high-temperature conditions (32 degrees C). Changes in pigment content and the micromorphology of epidermal cells in petals were monitored. The main pigment in 'Excerea' carnation petals was pelargonidin-3-malylglucoside (Pg3MG). A 48-70% reduction in Pg3MG occurred between day-5 and day-15 in petals kept under high-temperature conditions. Petal colour changes, as determined by lower C* and h degrees values using a colourimeter, were consistent with the reduction in Pg3MG content. Sucrose [1% (w/v)] in the vase water was effective at inhibiting the reduction in pigment content in petals kept under high-temperature conditions. An enlargement of epidermal cells occurred on both the abaxial and adaxial surfaces of petals between day-5 and day-15, irrespective of petal position, temperature conditions, or the composition of the vase solution. This enlargement in epidermal cells could cause the change in appearance of the flowers.