How Sage and Rosemary Essential Oils Regulate Postharvest Senescence and Extend the Vase Life of Cut Gladiolus Spikes

The production of cut flowers has substantial economic potential, and therefore, extending their lifespan has been the main focus of several floriculture researchers. Despite the increased marketable value of gladioli, their spikes rapidly lose their visual value and postharvest quality, accompanied by a short vase life. Unfortunately, most floral preservatives used to extend the flower lifespan have hazardous impacts; thus, providing eco-friendly alternatives has spurred immense interest among scientists. Sage and rosemary essential oils (EOs) seem to be effective eco-friendly flower preservatives due to their content of antimicrobial and antioxidant compounds. This study was therefore conducted to investigate whether using sage or rosemary EOs as novel preservative solutions can enhance the quality and prolong the vase life of cut gladiolus spikes. Gladiolus spikes were subjected to several concentrations (0, 50, 100, 150 and 200 mg L⁻¹) of sage or rosemary EOs in a vase solution. All levels of both EOs significantly prolonged the vase life of gladiolus spikes, increased their water uptake and enhanced floret opening compared to the control. The vase life was increased by 88.16 and 84.76% by applying 150 or 100 mg L⁻¹ of sage or rosemary EOs, respectively, compared to the untreated spikes. Sage and rosemary EO treatments markedly decreased bacterial populations, preserved the chlorophyll content, decreased H₂O₂ production and retarded the accumulation of malondialdehyde (MDA), and therefore preserved the membrane stability relative to the control. Furthermore, the total phenols and the antioxidant enzyme activities of catalase, glutathione reductase and ascorbate peroxidase were significantly increased due to sage or rosemary EO applications. In conclusion, sage or rosemary EOs may be applied as innovative, eco-friendly alternative preservatives to the communal chemicals used as preservatives in the cut flower industry.