Impact of alpha-ketoglutarate treatment on enhancing vase life of chrysanthemum by enhancing antioxidant systems and suppressing ethylene biosynthesis

Chrysanthemum is a globally valued cut flower with substantial commercial importance; however, its postharvest longevity is often limited by rapid senescence. This study investigated the application of alpha-ketoglutarate (AKG), a cost-effective and environmentally friendly metabolic intermediate, for extending the vase life of cut chrysanthemum flowers. The effects of 5 mM AKG (compared to a 0 mM control) on vase performance, physiological traits, biochemical composition, and the molecular regulation of ethylene biosynthesis were systematically evaluated. Our results demonstrated that 5 mM AKG significantly prolonged vase life by improving water balance and enhancing flower hydration through increased water uptake. The treatment effectively reinforced the antioxidant defense system by increasing the contents of glutathione, ascorbic acid, total phenolics, and flavonoids, while stimulating the activities of catalase (CAT) and superoxide dismutase (SOD). Consequently, AKG inhibited the accumulation of reactive oxygen species (ROS), leading to a marked reduction in malondialdehyde (MDA) levels, electrolyte leakage (EL), and lipoxygenase (LOX) activity. Furthermore, AKG application suppressed ethylene (ETH) production by downregulating the activities of 1-aminocyclopropane-1-carboxylic acid synthase (ACS) and oxidase (ACO), which was further confirmed by the reduced expression of CmACS1 and CmACO1 genes. Collectively, these findings demonstrate that 5 mM AKG represents a sustainable and eco-friendly strategy for enhancing the postharvest quality and longevity of cut chrysanthemums by integrating metabolic stability with hormonal regulation.