Physiology and Biochemistry of Flower Senescence: Mechanisms, Regulation and Implications for Postharvest Longevity
Flower senescence represents a genetically programmed and tightly regulated terminal phase of floral development that plays a critical role in reproductive success and postharvest performance of ornamental and horticultural crops. This review provides a comprehensive synthesis of the physiological and biochemical processes governing flower senescence, with emphasis on hormonal control, metabolic alterations and cellular signaling mechanisms. Ethylene acts as a primary regulator in many species by inducing senescence associated gene expression, whereas ethylene independent pathways also contribute to senescence regulation, reflecting species specific variability. Key physiological changes include deterioration of membrane integrity, disruption of water relations, reduced respiratory efficiency and loss of cellular homeostasis. Biochemically, senescence is marked by enhanced generation of reactive oxygen species, lipid peroxidation, degradation of proteins and nucleic acids and coordinated modulation of antioxidant defence systems. Alterations in carbohydrate metabolism, sugar signaling and secondary metabolites further influence the progression of senescence. The review has also highlighted the roles of calcium signaling, polyamines, nitric oxide and programmed cell death in regulating senescence responses. Understanding of these integrated physiological and biochemical mechanisms is essential for developing effective strategies to extend floral longevity and improve postharvest quality.