S05 - Session P2 - 1-MCP and KMnO4 affect the ethylene accumulation but not the respiration rate of stored Chrysanthemum cuttings

Authors: Lieven Van de Vondel *, Annelies Christiaens, Peter Ragaert, Frank Devlieghere, Marie-Christine Van Labeke

Ethylene affects many processes in plants including senescence. The effect of ethylene on plants depends on the genotype, the plant tissue and phenological stage among other things. Ethylene related effects such as an enhanced respiration rate are undesired during storage because they cause quality loss. These deteriorative effects can be reduced by scrubbing ethylene from the atmosphere with scavengers, or by using 1-methylcyclopropene (1-MCP) that binds the ethylene receptors in plants. Chrysanthemum cuttings, used for the production of potted Chrysanthemum, are highly perishable. Preliminary measurements have shown that ethylene accumulates in hermetically closed bottles and is present the first days after packaging in macroperforated foil. in the storage environment of Chrysanthemum cuttings. In this research, the effect of ethylene on the respiration rate of two cultivars of Chrysanthemum cuttings with different storability is examined at two different temperatures. In two separate experiments, Chrysanthemum cuttings were divided into a control group and a group treated with excess amounts of KMnO4 (first experiment) or 1-MCP (second experiment). Both groups were further divided and stored at 2°C or 7°C . Cuttings were put in hermetically closed bottles. Before closing, the headspace composition was modified to 10% oxygen + 90% nitrogen. The oxygen concentration was measured as a function of time and ethylene levels were measured once just before 0% oxygen was reached. KMnO4 was able to reduce the ethylene concentration by 40% for bottles measured after 4 to 5 days up to 60% for the bottles measured after 7 days. 1-MCP resulted for cv1 and cv2 respectively in ethylene levels 9.5× and 7× higher at 7°C but only 3× and 1.7× higher at 2°C. However, nor KMnO4 or 1-MCP treatment affected the respiration rate. It can be concluded that ethylene does not influence the respiration rate of Chrysanthemum cuttings during storage.