The Effect of Vase Solutions Containing Cobalt, Cerium, and Silver Nanoparticles on Postharvest Life and Quality of Cut Birds of Paradise (Strelitzia reginae) Keywords: Antioxidant Enzymes, Hydrogen Peroxide, Nanosil, Vascular Blockage.

A study was conducted on increasing the postharvest quality and vase life of cut Strelitzia reginae flowers based on a randomized complete design with 10 treatments in three replications. The experimental treatments included cobalt chloride (CoCl2) (250 and 500 mg L-1), cerium nitrate (Ce (NO3)3) (100, 300, and 600 μM), silver nanoparticle (SNP) (20 and 40 mg L-1), and Nanosil (2000 and 4000 μM) applied as the 24-hour pulse. Distilled water was used as the control. Results showed that the longest vase life (11.68 days) was obtained from the application of 300 μM Ce(NO3)3, but it did not significantly differ from the treatments of 100 and 600 μM Ce (NO3)3, 500 mg L-1 CoCl2, and 20 mg L-1 SNP. The best treatments in increasing water uptake and dry matter, preserving fresh weight, and reducing stem-end and vase solution bacteria were 300 and 600 μM Ce (NO3)3. The lowest malondialdehyde accumulation (0.09 nmol g-1 FW) and the highest activity of peroxidase (0.147 nmol g-1 FW) and catalase (1.02 nmol g-1 FW) were obtained from the plants treated with 300 μM Ce(NO3)3 in the vase solution. The highest sepal flavonoid (0.493 %) was related to the treatment of 2000 μM Nanosil. The control plants exhibited the greatest loss of fresh weight and the lowest values of the recorded traits. Based on the results, it is recommended to use a vase solution containing 300 μM Ce (NO3)3 and 3 % sucrose to preserve the quality and increase postharvest vase life of cut S. reginae flowers