Alstroemeria is one of the most popular cut flowers in Europe, due to its postharvest longevity and a wide colour palette. However, premature leaf yellowing reduces the ornamental value of the flowering stems even before opening of the secondary florets in cymes. The aim of this study was to evaluate the use of sucrose, gibberellin and 8-hydroxychinoline citrate as postharvest treatments of cut Alstroemeria ‘Dancing Queen’.
Several “flower models” were used to distinguish the effects of the chemicals on senescence of flowers and leaves in the above cultivar. Flowering stems were harvested in November 2011 and March 2012 and the response to treatments for both dates differed: while the longevity of primary and secondary florets was prolonged by the standard preservative (8-HQC+S) in the autumn, there was no difference for the spring collection date. For the March harvest, the secondary flower buds opened faster than for the November harvest, where bud opening was generally hastened by 8-HQC+S. Also, the flower model affected floret longevity and changed the response to the treatments: florets on defoliated flowering stems responded better to the preservative than those on stems with leaves. Florets from different flower models differed in diameter: those from complete stems were usually larger than those from isolated cymes. The secondary florets were much smaller than the primary florets, especially in isolated cymes. Both, GA3 and the standard preservative significantly increased the second floret diameter in all models; however, there were no additive effects of the treatments. GA3 significantly postponed leaf yellowing in all floral models while the sugar-containing preservative had little effect. Generally, the flower model had significant effect on leaf longevity.