Carbohydrate depletion causes rapid leaf necrosis in cut Chrysanthemum

Chrysanthemums are the second-largest exported cut flower worldwide for their variety of shapes, colors, and forms;?however, the leaves of some commercial cultivars exhibit rapid leaf necrosis during the first week in the vase. This?characteristic severely impacts consumer perception of plant quality. Thus, this problem is a primary concern for?growers, and the causes of this phenomenon are not known.Experiment with disbud and spray formsTwo experiments were performed in other to identify?the cause of rapid leaf necrosis in cut chrysanthemum leaves commercially grown in Colombia and shipped to?Clemson University for vase life evaluation. The first experiment evaluated the leaf performance of Chrysanthemum?'GreenScreen', 'Bomber Green', 'Peridot' and 'Shrek' grown with two flower forms: one flower per stem (disbud) vs.?8-10 flowers per stem (spray). The resultsStems with spray form showed leaf necrotic symptoms while stems with disbudded?forms showed good quality leaves after 10 days. This result can be related with sink-source dynamics. Spray stems depleted carbohydrate in leaves due to high sink demand resulting in rapid leaf necrosis, while disbud stems had lower sink demand resulting no leaf necrosis. Experiment with sucrose concentrationsThe second experiment evaluated the effect of sucrose concentrations in the vase solution following shipping. Stems of Chrysanthemum 'Paintball sunny', 'Mark Twain', 'WhatsApp', 'Peridot', 'Shrek' and 'Bomber Green' were placed in vases with a solution of 0%, 10% or 20% sucrose. Stems with 0% sucrose in the vase solution presented severe leaf necrotic symptoms after 2 days, while stems with 10% or 20% sucrose presented very low levels of leaf necrosis or no symptoms after 10 days. Conclusions of both experimentsTogether, the results from both experiments suggest that the rapid leaf necrosis of chrysanthemum is related with carbohydrates depletion in the leaves during postharvest. ? SourcesCarbohydrate depletion causes rapid leaf necrosis in cut ChrysanthemumAna Maria Borda, Shara Ortiz & James E FaustPostharvest Unlimited Conference & Postharvest Ornamentals Symposium, Wageningen University & Research, May 2023https://www.wur.nl/en/show/postharvest-unlimited-conference-postharvest-ornamentals-symposium.htmPicture by Florecica, https://www.florecica.com/productos/crisantemo-margaritas/crisantemo-spray-rados-186