Preservative solutions containing boric acid delay senescence of carnation flowers

Abstract

We investigated the effect of a preservative solution containing boric acid on the senescence of cut carnation flowers (Dianthus caryophyllus L. cv. Master). A 24-h pulse treatment with the preservative solution containing 50, 75 or 100 mM boric acid or continuous treatment with 1 mM boric acid resulted in strong inhibition of the climacteric ethylene production. Both the pulse and continuous treatments significantly increased flower longevity. Free and conjugated 1-aminocyclopropane-1-carboxylic acid (ACC) and ACC oxidase activity increased in carnation petals during senescence, although significantly less in boric acid-treated carnations than in control flowers. The levels of putrescine increased as senescence progressed in both control and boric acid-treated carnations and an increase in spermidine levels was higher in treated carnations. Abscisic acid levels in petals also increased during senescence, but much less in boric acid-treated carnations. It is concluded that boric acid prevents the early rise in ethylene production and considerably improves carnation vase life.