Preservative solutions containing boric acid delay senescence of carnationflowers

We investigated the effect of a preservative solution containing boric acid on the senescence of cut carnation flowers (Dianthus caryophyllus L. cv. M aster). A 24-h pulse treatment with the preservative solution containing 50 , 75 or 100 mM boric acid or continuous treatment with I mM boric acid resu lted in strong inhibition of the climacteric ethylene production. Both the pulse and continuous treatments significantly increased flower longevity. F ree and conjugated 1-aminocyclopropane-1-carboxylic acid (ACC) and ACC oxid ase activity increased in carnation petals during senescence, although sign ificantly less in boric acid-treated carnations than in control flowers. Th e levels of putrescine increased as senescence progressed in both control a nd boric acid-treated carnations and an increase in spermidine levels was h igher in treated carnations. Abscisic acid levels in petals also increased during senescence, but much less in boric acid-treated carnations. It is co ncluded that boric acid prevents the early rise in ethylene production and considerably improves carnation vase life. (C) 2001 Elsevier Science B.V. A ll rights reserved.