Prolonging Vase Life of Carnation Flowers Using Natural Essential Oils and itsImpact on Microbial Profile of Vase Solutions

This experiment was conducted during the two summer seasons; 2008 and 2009. Two cultivars of Dianthus caryphyllus L. were used; Farida and Madam Collate. Four essential oil treatments were used versus two controls; Tap water and 8-Hydroxyquinoline (8-HQ). These essential oils were extracted from mandarin, coriander, dill and clove. The maximum vase-life over the two seasons was recorded with dill oil followed by coriander in cv. Farida and with 8-HQ in cv. Madam Collate. The essential oils treatments showed accumulative significant reduction percentages in flower fresh weight, which increased by decreasing the used oil concentrations. The accumulative reduction percentage in flower fresh weight and the average flower dry weight showed negative significant correlation coefficients. The relative increased percentages in net water uptake were 10.93 and 7.95% in 8-HQ for both cultivars. The net water uptake had the greatest values with those flowers kept in solution containing dill followed by clove oils in cv. Madam Collate and by mandarin oil in cv. Farida. The highest positive correlation coefficient was recorded between vase life and net water uptake. The highest pH value was observed in vase containing tap water for both cultivars. In comparison, due to different treatments application, the pH values were significantly changed to a fairly acidic. These treatments were ranked, in this respect, at descending order as follows; dill oil, 8-HQ, mandarin, coriander and clove with both cultivars. The highest mean count of total spore-forming bacteria was recorded in the tap water vase solutions, while the lowest counts were with coriander oil. In vase solution containing dill oil, the log count of molds decreased as the dose concentration increased. The same trend was observed in cv. Madam Collate during the seasons. Counts of cellulose decomposing microorganisms were increased by extending the life of the carnation cut flowers in the vase solutions. All the examined preservatives, in particular 8-HQ, and the oils of dill, clove and coriander greatly suppressed proliferation of cellulose decomposers and resulted in flower densities compared with control solutions. The anatomical study indicated that, cv. Farida flower stalks greatly severe from more exposure to microorganisms attack in vase solution, especially cellulose decomposing microorganisms which penetrate tissues as lethal and blockage parasites. These negative influences on cv. Farida could be an evidence for explaining its rapid senescence and the longevity of the flowers of cv. Madam Collate