An Investigasion of the Possible Improvement of Cut Rose Flower cv.  Red Old Longevity Employing Organic Treatments vs. Silver Thiosulfate

Global concern of protection of the environment has led to researches on the effects of plants, natural extracts and organic materials to help maintain the postharvest quality of horticultural crops. Throughout the present study, the effects of such natural products as: mint, thyme, savory, rosemary extracts, S-carvone, and humic acid on postharvest life of cut rose flowers, and the potential of these products in being alternative to such hazardous chemical compounds as silver thiosulfate, were evaluated. Concentrations of 1, 2.5, 5, 7.5, and 10% herbal extracts; 10, 25, 50, 75 and 100 mgl-1 of humic acid; 0.1, 0.2, 0.3, 0.4, and 0.5 mM S-carvone vs. 1 mM of silver thiosulfate were used to have their effects evaluated on vase life, relative fresh weight, flower diameter and on chlorophyll content of cut roses. Experiments were carried out as based on a completely randomized design of 5 replications.The results indicated that 1 mM of silver thiosulfate and 50 mgl-1 humic acid treatments significantly (P≤0.05) increased the vase life of cut rose flowers (26 and 24 days, respectively) as compared with control (17.4 days). Moreover, 0.1 mM S-carvone had a positive effect on longevity of the cut flowers. Flowers treated with 0.3 mM S-carvone and 1 mM silver thiosulfate bore the highest relative fresh weights in early and final (17th and 19th) days of the experiments, respectively. However, plant extracts of 1% mint and 7.5% savory, significantly decreased vase life of cut rose flowers as compared with control. Mint extract in concentration of 10% showed significantly negative effect on flower diameter in the second and third assessments. Also, in the last two measurements, the highest diameter was obtained at concentration of 1 mM of silver thiosulfate. No significant differences were observed in chlorophyll content for all the applied treatments. In total, the results indicated that silver thiosulphate exerts the highest impact on increasing cut rose flowers, longevity, but humic acid and S-carvone treatments can be recommended as potentially effective alternatives to this non-organic substance.