|Riassunto in Inglese:|
Flower color, an important feature biologically and commercially, is based on four natural pigments - flavonoids, carotenoids, betalains and chlorophylls. Temperature, light, nutrition – as well as additions of sugar, salt, or metals to the conservation water – has an effect on pigmentation. We investigated the effects of K-sulphate and/or sucrose on flower color in leaf treatments applied 30 to 10 days before harvest to four Asiatic Lily (Lilium × elegans Thunb.) cultivars during the winter and summer. Colors of tepals were evaluated by a portable spectrocolorimeter that calculates the standard CIE L*a*b* coordinates and the color differences (E). After leaf treatments during both seasons, cultivars with flowers with high red components (e.g. the purple 'Fangio' and the pink 'Brindisi') showed significant improvements in color quality. The orange-flowered 'Tresor' showed improvement only if K-sulphate and Mix (K-sulphate and sucrose) solution treatment was applied during the summer. The yellow-flowered 'Menorca' was not affected by treatments during either summer or winter forcing season. Especially in the winter, a significant reduction in flower abortion was observed for cut flowers of all cultivars. In summer only 'Fangio' and 'Tresor' showed a reduction in flower abortion. Also, flower size and longevity were improved by the leaf treatment. The results, obtained from a commercial nursery operation, demonstrate that lily growers can adopt a very simple and inexpensive treatment to improve important qualitative traits of their product.