Effect of Calcium and Silver Nanoparticles on Morphophysiological Characteristics of Cut Rose Flower

 Rose is one of the important cut flowers, which has different types. Extending the vase life of rose-cut flowers is very important in the floriculture industry. Every year, due to the lack of proper storage conditions after harvesting, the efficiency of rose production decreases. Therefore, always using materials that help increase the shelf life of cut flowers is valuable. Today, substances that improve the quality of cut flowers are very important. They include materials such as calcium and silver. Nanoparticles are materials with sizes smaller than 100 nanometers. On the other hand, the important role of calcium and silver in improving quality of the cut flowers is interesting for scientists. In this research, the effect of pre-harvest application of calcium nanoparticles along with the post-harvest application of silver nanoparticles on the morpho-physiological characteristics of rose cut flowers (CV: Classic Cezanne) was investigated.
 
 The current research was carried out during the year 2021 in a commercial rose production greenhouse in Nazarabad city. calcium nanoparticles with different concentrations (0, 5 and 10 mg.L-1) were sprayed on rose bushes every ten days (two months before harvest). After harvesting the flowers and transferring them to the laboratory, silver nanoparticles were added to the flower preservation solution at different concentrations (0, 5 and 10 mg.L-1). After harvesting, the traits (vase life, flower diameter, fresh weight, vase solution uptake, total protein, malondialdehyde and superoxide dismutase) were evaluated on the treated flowers (on days 0, 4, 8 and 12). Experiment was performed as factorial based on completely randomized design, included 9 treatments with 3 replications.
 
 Based on the results of analysis of variance of treatment with calcium nanoparticles and silver nanoparticles for the quality of shelf life at the 1% level of Duncan's test, it showed a significant difference. Also, based on the results, the highest amount of vase life is related to the treatment of calcium nanoparticles with a concentration of 10 mg.L-1 with the silver nanoparticle treatment in the time after harvesting was at concentrations of 5 and 10 mg (11 days) and the lowest amount was related to the control treatment (7 days).Vase life increased under the effect of treatment with calcium nanoparticles and silver nanoparticles (10 mg.L-1) and caused an increase of 4 days compared to the control (0 mg.L-1) The treatments decreased the amount of malondialdehyde and also increased the relative amount of absorbed solution, total protein and superoxide dismutase enzyme. Based on the results of this study, calcium and silver nanoparticles improved qualitative traits. The simultaneous treatment of calcium and silver nanoparticles (concentration 10 mg.L-1) compared to the control (0 mg.L-1) caused an increase (14%) in flower diameter, fresh weight (12%), vase solution uptake (46%), superoxide dismutase (21%) and malondialdehyde reduction (37%). Two other important findings emerged from this work: (1) The nanoparticles used in this experiment caused the activation of the enzyme antioxidant system in the treatments (2) The simultaneous treatment of nanoparticles calcium before harvesting and silver nanoparticles treatment after harvesting by activating the antioxidant enzyme system and maintaining the ability to absorb the solution increased the vase life of rose cut flowers. In general, the treatment with calcium nanoparticles at a concentration of 10 mg. L-1 before harvesting and the treatment with silver nanoparticles at a concentration of 10 mg.L-1 after harvesting were the most effective treatments in most traits.
 
 Calcium is one of the most effective factors in increasing the vase life of rose cut flowers. Treatments containing calcium increase absorption of vase solution uptake. The treatment of calcium nanoparticles increases the total protein and superoxide enzyme compared to the control, so that the simultaneous use of silver and calcium nanoparticles increases the vase life of rose-cut flowers compared to the control. Calcium probably activated a chain of reactions by activating the message transmission system and caused the expression of genes involved in the antioxidant system of the samples. silver nanoparticles by affecting the absorption of vase solution uptake and reducing the amount of malondialdehyde and increasing the total protein and superoxide dismutase enzyme compared to the control, increase the vase life of cut flowers. According to the results obtained from the present research, it can be concluded that use of calcium nanoparticles with silver nanoparticles had great effects on most of traits in compared to control treatment. The use of calcium nanoparticles with silver nanoparticles improves the vase life conditions by increasing water uptake and consequently increasing the relative fresh weight.