Effect of growth regulators on postharvest characteristics of Zantedeschia aethiopica

Treating cut leaves of Zantedeschia aethiopica with aqueous solutions of gibberellic acid (GA(3)) considerably extended their display life, whether applied as a 24 h pulse treatment, or as a brief postharvest dip. In contrast, a standard preservative solution used to prolong the longevity of cut flowers (8-HQC + sucrose) was deleterious to Zantedeschia foliage, reducing display life several fold from that of the water control. After harvest, chlorophyll content of the leaves fell more or less rapidly depending on the postharvest treatment, falling most rapidly in leaves placed in the 'preservative' solution and relatively gradually in leaves that had been treated with GA(3). Leaf senescence was also associated with changes in characteristics of the cell sap, namely increased pH and electrical conductivity, parameters that may be a useful and rapid means of determining the senescence status of cut flowers during marketing. (C) 2001 Elsevier Science B.V. All rights reserved.