Document Type : Research Paper



Growth, nutrients concentration and quality of rose flowers (Rosa hybrida L.( were evaluated under different potassium (K) and calcium (Ca) levels in the nutrient solution. This experiment was conducted as factorial in a randomized complete block design with four replicates on rose plants cultivar “Vendetta” under hydroponic conditions during 2007-2008 at Safi Abad Agricultural Research Center, Dezful, Iran. Rose plants were grown and irrigated with nutrient solutions having three K concentrations of 1.0, 5.0 and 10.0 mM in combination with two Ca concentrations of 1.6 and 4.8 mM. The results indicated that vegetative growth indices were not affected by different K and Ca concentrations in the nutrient solutions. Furthermore, increasing the K concentration in the solution significantly increased (P< 0.01) K concentration in rose parts, but markedly suppressed the Ca concentration of roots, leaves and petals as well as the Mg concentration of roots and leaves in rose plants. A regression relationship (r2= 0.78) was observed between the Ca and K concentrations of the leaves. However, application of Ca decreased K concentration in all of the rose parts and also increased the Ca concentration in various rose parts, expect leaves. At both harvesting dates of rose flowers, application of K at a concentration of 5.0 mM in nutrient solution, enhanced yield of the flowers more than the other K levels. Meanwhile, increasing the Ca concentration from 1.6 to 4.8 mM, markedly increased the yield of flowers. These results suggest that in order to decrease antagonistic effects between K and Ca and at the same time improving rose nutritional balance and yield, the application of combined 5.0 mM K and 4.8 mM Ca are recommended for Vendetta cut rose production in hydroponic condition.