Morphological and Physiological Changes and Ethylene-Related Gene Expression During Petal Senescence in Red-Flowered Strawberry ‘140’

Red-flowered strawberry possesses both ornamental and edible value, but its short single-flower lifespan severely limits its ornamental potential. In this study, petals of the red-flowered strawberry cultivar ‘140’ were collected at five developmental stages (large bud, half-bloom, full-bloom, initial withering, and withered) to systematically analyze the senescence process from morphological characteristics, physiological, and ethylene-related gene expression perspectives. The results showed that the epidermal cell breakage rate increased continuously during petal senescence, with lower epidermal cells consistently exhibiting higher breakage rates than the upper epidermal cells. Moisture content decreased progressively, while relative electrolyte leakage, malondialdehyde, hydrogen peroxide, and superoxide anion contents increased continuously. Superoxide dismutase, peroxidase, and catalase activities, as well as glutathione content, exhibited unimodal responses, peaking at different stages. Both ethylene and abscisic acid contents increased and then decreased, with ethylene showing greater amplitude and faster rate of change. The ethylene biosynthesis gene FaACO1 and signaling genes FaETR1, FaETR2, FaEIN2, FaEIN7, FaERF13, and FaERF118 were significantly upregulated at full-bloom or initial withering stages, with FaERF118 showing the highest and continuously increasing expression. These findings indicate that water loss, membrane lipid peroxidation, and reactive oxygen species accumulation synergistically drive petal senescence, with the ethylene signaling pathway playing a key regulatory role.