Multi-Walled Carbon Nanotubes Improve the Development of Chrysanthemum × morifolium (Ramat.) Hemsl. ‘Jinba’ Inflorescences

The application of cut flower preservation technology can significantly enhance both the ornamental and economic value of fresh-cut flowers. Research on vase solutions has become a concentrated area in current studies on cut flower preservation. Multi-walled carbon nanotubes (MWCNTs), as a type of carbon nanomaterial with bactericidal and membrane-penetrating properties, can be used as a component in vase solutions. This supplementation of energy substances aims to improve antioxidant enzyme activity, thereby enhancing the postharvest quality of cut chrysanthemums. In this study, deionized water and a standard preservative solution were employed as control groups to compare the effects of MWCNTs applied at different concentrations, combined with common preservatives such as sugar and 8-hydroxyquinoline, on the postharvest flowering and preservation of Chrysanthemum × morifolium ‘Jinba’. By observing the distribution of MWCNTs in the tissues surrounding the cut and changes in water content, carbon sources, osmoregulatory substance levels, and the expression of relevant key genes, a formulation with excellent postharvest treatment effects was identified. Preliminary investigations into its action and mechanism were also conducted. The results indicated that the combined treatment with 5 mg L−1 MWCNTs, 30 g L−1 sucrose, and 0.2 g L−1 8-hydroxyquinoline effectively promoted water and sugar uptake in chrysanthemum flowers, accelerating bud opening, maintaining larger inflorescence diameter, and extending the vase life. Ultimately, this enhanced the ornamental value of cut chrysanthemums. These research findings provide theoretical and experimental foundations for the application of multi-walled carbon nanotubes as auxiliary additives to improve the ornamental quality of cut flowers.