IMPROVEMENT OF CUT FLOWER QUALITY OPENING AND LONGEVITY BY PRE-SHIPMENT TREATMENTS

The quality and longevity of carnation and chrysanthemum flowers grown under non-optimal temperature and light conditions can be improved in comparison with flowers in bloom on the plant, by harvesting the flowers in the bud stage and opening them in a proper opening solution. A high sugar concentration is needed for optimal effect in carnations and certain chrysanthemum varieties.

The situation is often worse with flowers usually cut and shipped at the bud stage (like roses and gladioli). In many cases they fail to develop and survive as well as intact flowers. The main reasons for this are (a) lack of sufficient carbohydrate reserves needed for growth and energy and (b) difficulties in water absorption.

By treating the stems of the cut gladiolus flowers with solutions containing high sugar concentrations (10–25%) and bactericides, it is possible to"load"the flower stems with enough sugar for their development and full opening. Water balance is improved in treated flowers, mainly by increased water uptake.

Several metabolic sugars were equally effective, but not mannitol. Water potential of gladiolus and chrysanthemum flowers was considerably decreased in sugar-treated flowers, thus permitting better osmotic water uptake.

Proper pre-shipment treatment with opening solution may also improve the colour of certain rose cultivars (Baccara, Super Star, Carol and Dr. Verhage).