Nano-Selenium in the holding solution promotes rose and carnation vase life by improving both water relations and antioxidant status

Nano-selenium (nano-Se) is an eco-friendly and inexpensive compound. The potential of including it in the holding solution to stimulate vase life was investigated by conducting two experiments. In the first one, dose-response curves were generated by applying different nano-Se concentrations (0–1 and 0–1.5 µM for rose and carnation, respectively) in the holding solution of three cultivars per species. Nano-Se in the holding solution improved vase life in all cases, besides one carnation cultivar. The optimal concentration was considerably higher in carnation as compared to rose (1–1.5 and 0.25–0.75 µM, respectively), and was cultivar dependent. Nano-Se improved cut flower water balance by enhancing water absorption more than transpiration. In the second experiment, the optimal holding solution nano-Se concentration was employed to evaluate the underlying processes in the two cultivars per species, where vase life was mostly increased. Physiological and biochemical characteristics were assessed in both leaf and petal tissues. Nano-Se ameliorated chlorophyll degradation, electrolyte leakage and lipid peroxidation owing to up-regulation of both enzymatic and non-enzymatic antioxidants. In conclusion, the nano-Se-induced vase life extension was associated with both upgraded antioxidant status and improved water relations, setting it as a low-cost and environmentally-safe agent of prolonging floral longevity.