Spatial and temporal dynamics of carnation-scented flowers in Lagerstroemia 'Ning Xiang 3

Floral scent is an essential attribute for plant reproduction and ornamental plant industry. In Lagerstroemia genus, taxa with distinct fragrances are rare, thus limiting their economic value. Using headspace solid-phase micro-extraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) (HS-SPME-GC-MS), floral scent components of L. 'Ning Xiang 3 ' (a fragrant cultivar blooming with pinkish-white petals) in different flowering periods, floral organs, and day-night times were measured. Overall, 67 volatiles were putatively detected at five flowering periods and the primary compound type was benzenoids/phenylpropanoids (P2: 50.75%; P3: 47.33%). Eugenol (clove odor) and geraniol (rose odor) were considered as the most characteristic scent compounds, leading to the carnation-scented attribute of L. 'Ning Xiang 3 ' flowers. Based on floral organ's specific analysis, we found that the composition of the whole flowers most resembled that of petals (Bray-Curtis dissimilarity index 0.48), indicating that the petals contributed conclusively to the floral scent. Additionally, the scent release dynamics observed in day-night times showed consistent variation (increasing first and then decreasing) with that in different flowering periods, suggesting that the early-blooming period (cool morning at 6:00-7:00 am) represents the peak period for L. 'Ning Xiang 3 ' floral fragrance production. The present study is expected to provide a theoretical and material foundation for the targeted breeding of Lagerstroemia fragrant germplasm, and promote the development of Lagerstroemia fragrance industry.