Volatile composition, emission pattern, and localization of floral scent emission in crabapple (Malus)

• M . 'Prairie Rose' exhibited the greatest diversity of unique compounds, predominantly terpenes. • The emission of floral scent compounds peaked during the flowering stage in three crabapples. • Petals significantly contributed to the overall floral scent in M . 'Lollipop' and M . 'Hydrangea'. • The entire petal functions as a large aromatic gland in three crabapples. Floral scent holds considerable ecological and industrial significance. Frequently cultivated crabapples are scentless and little research has been done on their aromatic properties, which has impeded the ecological and industrial exploration of fragrant crabapple cultivars. M . 'Lollipop', M . 'Hydrangea' and M . 'Prairie Rose' crabapple cultivars, known for their strong floral scent, high resistance and consistent flowering period, were selected to investigate their volatile composition, emission patterns, and floral scent emission localization. Gas chromatography-mass spectrometry analysis identified four primary groups of floral compounds in the three ornamental crabapple cultivars: aliphatic compounds (34 types, 47.88 %), benzenoids/phenylpropanoids (18 types, 25.35 %), terpenes (12 types, 16.90 %), and miscellaneous compounds (7 types, 9.86 %). M . 'Prairie Rose' exhibited the highest diversity of unique compounds, predominantly terpenes. Floral scent emission peaked during the flowering stage (S3) across three crabapples. Dissimilarity coefficient analysis revealed that petals significantly contributed to the overall floral scent in M . 'Lollipop' and M . 'Hydrangea'. Scanning electron microscopy demonstrated that the entire petal functions as a large aromatic gland in three crabapples. These findings provide valuable insights for breeding and industrial applications of fragrant ornamental crabapples.