Silver nanoparticles derived from Calotropis and Plumeria plants as a green approach to extend the vase life of Alstroemeria flowers

The cut flower industry is valuable due to the aesthetic features of cut flowers; therefore, maintaining product attractiveness during the postharvest period is essential in this industry. In cut Alstroemeria flowers, premature yellowing of leaves on the stem before petal drop is one of the major postharvest problems, which reduces the commercial value of the flower. The experiment was conducted as a completely randomized factorial design with three replications and nine treatments at the Agricultural Faculty Laboratory of the University of Hormozgan in 2024. The treatments included chemically synthesized silver nanoparticles and green silver nanoparticles synthesized from leaf extracts of Calotropis procera (Calotropis) and Plumeria rubra (Plumeria) at concentrations of 10, 15, and 20 ml L^-1. In addition, a 3% sucrose solution and distilled water were used as control treatments. All treatments except for the distilled water control contained 3% sucrose. The measured parameters included fresh flower weight, floret diameter, vase life, ion leakage, bud opening percentage, water uptake, total soluble solids, reducing sugars, total chlorophyll, anthocyanin, and the activities of ascorbate peroxidase and catalase enzymes. The findings clearly showed that the application of silver nanoparticles, especially those synthesized from Plumeria (NP) and Calotropis (NA) extracts, had a significant effect on improving physiological, biochemical traits, and vase life of cut Alstroemeria flowers. The results showed that the application of silver nanoparticles had a significant effect on improving the postharvest performance of Alstroemeria cut flowers. The longest vase life (18 days) and highest bud opening percentage (over 93%) were observed in the green Plumeria nanoparticles at 10 ml L^-1 (NP10), while the shortest vase life (13 days) was recorded in the chemically synthesized nanoparticles at 20 ml L^-1 (N20). The NP15 treatment increased fresh flower weight by approximately 22% and water uptake by 18% compared with the control. Moreover, the activities of ascorbate peroxidase (APX) and catalase (CAT) were 1.6‑fold and 1.4‑fold higher than those of the control, respectively. Given that biological nanoparticles appear to be more biocompatible, stable, and safer than chemical counterparts, their use in the postharvest management of ornamental flowers could potentially be a sustainable and environmentally friendly approach.