This experiment was conducted to investigate the effect of different ratios of potassium to calcium in nutrient solution on physiological traits, lifespan of cut rose and postharvest changes in roses. The experiment was conducted as a factorial based on a completely randomized design with two rose cultivars (Capitol and Magic Red), five ratios of potassium to calcium in nutrient solution (4:4, 6:4, 6:3, 8:3 and 10:2) and three replications. Increasing the ratio of potassium to calcium in nutrient solution led to the accumulation of potassium but decreased calcium in leaves. In addition, the potassium to calcium ratio of the leaves was affected by the potassium to calcium ratio of the nutrient solution, and the highest potassium to calcium ratio was recorded for leaves fed with a nutrient solution with a ratio of 10:2, and the lowest potassium to calcium ratio was obtained for leaves fed with nutrient solutions with potassium to calcium ratios of 4:4 and 6:4. The highest chlorophyll index was recorded for the Capitol cultivar, and different potassium to calcium ratios of the nutrient solution had different significant effects on chlorophyll fluorescence. Increasing the potassium to calcium ratio reduced the cut flower lifespan of both cultivars. The highest amount of petal necrosis occurred at a ratio of 10:2, and the Magic Red cultivar had the highest sensitivity and the highest percentage of necrosis. The most appropriate ratio of potassium to calcium in terms of nutritional balance, reduction of antagonistic effects of potassium and calcium, post-harvest quality and longer shelf life of cut roses was obtained at a ratio of 6:4.
Comments