Search Results (89)

Background: Phoebe zhennan and Phoebe chekiangensis are valuable evergreen trees recognized for their unique aromas and ecological significance, yet the organ-related distribution and functional implications of aroma-active volatiles remain insufficiently characterized. Methods: In this study, we applied an integrated GC-MS-based volatile metabolomics approach combined with a relative odor activity value (rOAV) analysis to comprehensively profile and compare the volatile metabolite landscape in the seeds and leaves of both species. Results: In total, 1666 volatile compounds were putatively identified, of which 540 were inferred as key aroma-active contributors based on the rOAV analysis. A multivariate statistical analysis revealed clear tissue-related separation: the seeds were enriched in sweet, floral, and fruity volatiles, whereas the leaves contained higher levels of green leaf volatiles and terpenoids associated with ecological defense. KEGG pathway enrichment indicated that terpenoid backbone and phenylpropanoid biosynthesis pathways played major roles in shaping these divergent profiles. A Venn diagram analysis further uncovered core and unique volatiles underlying species and tissue specificity. Conclusions: These insights provide an integrated reference for understanding tissue-divergent volatile profiles in Phoebe species and offer a basis for fragrance-oriented selection, ecological trait evaluation, and the sustainable utilization of organ-related metabolic characteristics in breeding and conservation programs. Full article

Butterflies have nectar-feeding preferences based on various floral characteristics, including flower shape, size, color, fragrance, and nectar composition, which in turn affect their survival, reproduction, and roles in pollination. The National Botanical Garden (NBG) in Lalitpur, Nepal, holds a variety of flowering plants and butterfly populations, providing a suitable study site to test the hypotheses on floral preferences of butterflies. This study assessed the floral preferences of the butterfly community in the NBG based on flower color, the origin of flowering plants (native and alien), and the type of plants (herbs and shrubs). It also tested the association between butterfly proboscis lengths and corolla tube lengths of flowers. Data were collected from 10 blocks (each 5 × 5 m²) through direct observation during the spring and autumn seasons, from March to October 2022. A total of 24 species of butterflies were recorded during the study period, with the chocolate pansy (Junonia iphita) being the most abundant. The relative abundance of pink flowers was higher in the NBG, but the butterflies’ visitation frequency was significantly higher on yellow flowers (p < 0.05) than on other colors. The visitation frequencies of butterflies significantly varied with the flowers’ origin and types. Butterflies visited flowers of alien origin more frequently than native ones (p < 0.05) and those of herbs over shrubs (p < 0.05). Flowers from alien plants, such as Calluna vulgaris and Viola tricolor, were among the most frequently visited. The proboscis length of butterflies showed a significantly strong positive correlation with the corolla tube length of flowers (τ = 0.74, p < 0.001). These results can inform conservation practices and garden management strategies aimed at supporting butterfly diversity through the intentional selection of floral resources. Full article

Flower fragrance is a crucial ornamental and economic trait of Dendrobium chrysotoxum, and the most abundant and diverse aroma-active compounds are terpenes. Terpene synthase (TPS) is the ultimate enzyme for the biosynthesis of various types of terpenes, and TPS genes were identified as the key regulators governing the spatiotemporal release of volatile terpene compounds. Until recently, the TPS gene family in D. chrysotoxum has remained largely unexplored. Our study characterizes the TPS genes in D. chrysotoxum and identifies 37 DcTPS gene family members. It helped identify the DcTPS genes, gene characteristics, the phylogeny relationship, conserved motif location, gene exon/intron structure, cis-elements in the promoter regions, protein–protein interaction (PPI) network, tissue specific expression and verification of the expression across different flowering stages and floral organs. Three highly expressed DcTPS genes were cloned, and their functions were verified using a transient expressed in tobacco leaves. Further functional verification showed that the proteins encoded by these genes were enzymes involved in monoterpene synthesis, and they were all involved in the synthesis of linalool. This study comprehensively expatiates on the TPS gene family members in D. chrysotoxum for the first time. These data will help us gain a deeper understanding of both the molecular mechanisms and the effects of the TPS genes. Furthermore, the discovery that three TPS-b genes (DcTPS 02, 10, 32) specifically drive linalool-based scent in D. chrysotoxum, will provide new insights for expanding the TPS-b subfamily in orchids and identifying the linalool synthases contributing to orchid fragrance. Full article

Spreading, the preliminary step in the production of green tea, is crucial for achieving superior tea quality. This study investigated the effects of spreading on the sensory quality and volatile compounds in green tea under varying intensities of yellow light, employing GC-E-Nose and targeted metabolomics. A notable improvement in overall sensory quality was noted in tea samples subjected to a higher intensity of 6000 Lux, which was characterized by a delightful floral fragrance. In total, 70 volatile compounds were successfully identified, with 61 volatiles detected across all five light intensities. Moreover, 21 pivotal odorants featuring odor activity value (OAV) levels higher than one were determined, among which β-ionone, β-damascenone, linalool, (E, Z)-2,6-nonadienal, and phenylethyl alcohol exhibited particularly high OAVs. Correlation analysis indicated that phenylethyl alcohol, linalool, and citral exhibited robust positive correlations with the majority of key odorants, suggesting their vital contribution towards aroma enhancement. These findings offer novel insights into the regulation of tea aroma through the manipulation of light intensity during the processing of green tea. Full article

Dixu tea is one of the characteristic tea germplasm resources of southeastern Yunnan, and is also a precious wild tea germplasm resource. Background: In order to further develop Dixu tea products and improve their flavor, this article studies the effects of different processing methods on the aroma quality of Dixu tea. Methods: A comprehensive analysis of the aroma quality of Diwei tea was conducted using HS-SPME combined with GC-MS and multivariate statistical analysis. A principal component analysis (PCA) was applied to process the detected volatile substances and an orthogonal partial least squares-discriminant analysis (OPLS-DA) model was established. We evaluated the contribution of major compounds in the tea aroma by calculating the odor activity value (OAV). Results: The results showed that a total of 67 compounds were identified. A total of 27 major aromatic volatile compounds (OAV > 1) were screened, and 17 key differential volatile compounds were identified in different tea samples, including octanoic acid, d-citrol, laurene, hexanal, citral, β-cyclic citral, trans-2-hexenal, γ-nonanolide, β-ionone, geranylacetone, 1,1,6-trimethyl-1,2-dihydronaphthalene, geraniol, methyl salicylate, linalool, nerolidol, and 7,11-dimethyl-3-methylene-1,6,10-dodecatriene. Combined with the OAV analysis, it is shown that a floral fragrance is a common feature of Guangnan Dixu tea varieties. In addition, white tea also has a fragrant aroma, while black tea, green tea, and bamboo tube tea are all accompanied by a fruity aroma. Conclusions: In summary, processing techniques regulate the aroma characteristics of various types of tea by changing the types and contents of volatile aroma compounds. This provides a theoretical basis for exploring and utilizing tea production resources in the future. Full article

Peony mead, an emerging fermented beverage, has attracted attention because of its unique flavor and health benefits. The dynamic changes in sensory quality and the molecular mechanisms involved during post-fermentation are still unclear, limiting its industrial production. In this study, GC-IMS (gas chromatography-ion mobility spectrometry) and UHPLC-MS/MS (ultrahigh-performance liquid chromatography–tandem mass spectrometry) were employed to systematically analyze the variations in aroma and quality of peony mead across aging stages. During the aging process, titratable acid content increased significantly, while soluble solids and reducing sugars decreased. Total phenol content initially rose but subsequently declined. Sensory analysis demonstrated that the sweet–acid balance and polyphenol content were critical in shaping the sensory characteristics of the product. Seventeen key volatile metabolites were identified via GC-IMS, with the 2-methyl-1-propanol dimer/polymer and 3-methyl-1-butanol dimer/polymer serving as potential characteristic markers. These key volatile metabolites underwent physicochemical reactions, yielding complex and coordinated aroma characteristics. UHPLC–MS/MS analysis revealed that nonvolatile metabolites changed significantly, which were driven by nonenzymatic reactions such as redox reactions, hydrolysis, and condensation. In addition, correlation analysis identified mechanisms by which key metabolites potentially contributed to sensory properties such as floral aroma, fruit fragrance, sweetness, sourness, etc. This study provided insights into quality changes during aging and supported the development of high-quality fermented beverages. Full article

This study aimed to investigate the content of major bioactive compounds and characterize the volatile and sensory profiles of Coffea canephora flowers and their infusions. Dried flowers from six selected genotypes of C. canephora trees and their infusions were analyzed for bioactive compounds using HPLC–DAD, while volatile organic compounds (VOC) were analyzed using GC–MS. Eight chlorogenic acids (CGA), seven phenolic acids, and the alkaloids caffeine and trigonelline were quantified in all methanolic flower extracts. Total CGA, phenolic acids, caffeine, and trigonelline contents in the methanolic extracts ranged between 342.8 and 1079.4 mg/100 g, 27.1 and 41.0 mg/100 g, 515.6 and 745.9 mg/100 g, and 453.8 and 645.2 mg/100 g, respectively. CGA, caffeine, and trigonelline were well extracted (84%, 91%, and 74%, respectively) when the flowers were infused in hot water. No free phenolic acids were identified in the infusions. Eighty-five VOC were identified in the flowers. Aldehydes, monoterpenes, esters, alcohols, monoterpene alcohols, acids, and ketones prevailed in order of the number of compounds. In the infusions, 38 VOC were accurately identified. Monoterpenes and monoterpene alcohols prevailed. In general, floral, jasmine and orange blossom, herbal, green coffee, woody, and sweet were the most cited sensory attributes for fragrance, aroma, and flavor. Considering the typically weak aroma of C. canephora seeds, the aroma and flavor of the flower’s infusions were surprisingly strong and pleasant, showing great marketing potential. Full article

There is a lack of theoretical evidence regarding the transformation of the aroma of Pu-erh tea (raw tea) during long-term storage. In this study, we comprehensively investigate the aroma characteristics of Pu-erh tea (raw tea) from the same manufacturer, stored for different storage times (7–21 years). Sensory evaluation and qualitative and quantitative analysis of volatile substances were performed on the experimental samples. The results showed that the aroma of Pu-erh tea (raw tea) changed from fruity/floral to smoky and fragrance during the storage process. A total of 290 volatiles were identified by HS-SPME/GC×GC-Q-TOF-MS. The key substances for the fruity/floral aroma are fenchene, (E)-1,2,3-trimethyl-4-propenyl-Naphthalene, (+/−-theaspirane, and decanal, and the key substances for the smoky aroma were 2-ethyl-Furan, camphene, 1-methyl-4-(1-methylethenyl)-Benzene, and cis-β-Ocimene. The key aroma substances for the fragrance aroma are 1-methyl-4-(1-methylethylidene)-Cyclohexene, α-Terpinene, trans-β-Ocimene, (E,E)-2,4-Heptadienal, octanal, 2,5-Dimethoxyethylbenzene, 2,4-Dimethylanisole, 1,2,3-Trimethoxybenzene, and 3,4-Dimethoxytoluene. This study helps us to understand further the aroma changes of Pu-erh tea (raw tea) during long-term storage. Full article

Rosa rugosa is an excellent aromatic plant species valued for both essential oil extraction and ornamental applications. This study aimed to evaluate its adaptive responses, bioaccumulation capacity, and production quality under cadmium (Cd) stress, providing insights for phytoremediation and sustainable agriculture. A controlled pot experiment was conducted using two cultivars (R. rugosa ‘Zizhi’ and its bud mutation R. rugosa ‘Baizizhi’) subjected to various Cd treatments. Growth parameters and physiological indices, such as antioxidant enzyme activities, chlorophyll content, photosynthesis rates, and floral volatile organic compounds, were systematically analyzed. Cd concentrations ranging from 5 to 50 mg·kg⁻¹ maintained plant growth, but significantly elevated antioxidant activities (SOD + 65.94–300.53%, POD + 37.58–75.06%, CAT + 12.48–12.62%) and chlorophyll content (+20.27–242.79%). In contrast, 400 mg·kg⁻¹ Cd severely inhibited growth, inducing chlorosis and leaf desiccation. Total floral volatiles showed a hormetic response, peaking at 200 mg·kg⁻¹ (+46.08%). Sesquiterpenoids showed greater Cd-responsiveness than monoterpenoids, though core aromatic profiles remained stable. The species exhibited root bioconcentration BAF > 0.1 and limited translocation TF < 1, indicating phytostabilization potential. Despite tolerance up to 400 mg·kg⁻¹, field application is recommended below 50 mg·kg⁻¹—a threshold exceeding China’s soil Cd limits (GB 15618-2018). These findings position it as a dual-purpose crop for ecological restoration and fragrance production in Cd-impacted areas. Full article

Wintersweet (Chimonanthus praecox) is known for its flowering in winter and its rich floral aroma; the whole flower is yellow and the inner petals are red. In this study, we chose the wintersweet genotypes HLT040 and HLT015 as the research materials, and studied the co-regulatory mechanism of color and fragrance of wintersweet through metabolomics and transcriptomics. This study found that there were more flavonoids in HLT015, and anthocyanins (cyanidin-3-O-rutinoside and cyanidin-3-O-glucoside) were only present in HLT015, but HLT040 contained more monoterpenes and FVBPs (phenylpropanoid volatile compounds) than HLT015. We constructed putative benzenoids and phenylpropanoid metabolism pathway as well as terpene metabolism pathways. We found some linkages between the different structural genes and metabolites for flower color and fragrance in wintersweet, and screened out 39 TFs that may be related to one or more structural genes in benzenoids and phenylpropanoid or terpene metabolism pathways. In the yeast one-hybrid assay, we found that CpERF7 was able to interact with the promoter of CpANS1, while CpbHLH50 and CpMYB21 interacted with the promoter of CpTPS4. This study provides a theoretical basis for understanding the co-regulatory mechanism of color and fragrance in wintersweet. Full article

Wuyi Rock tea (WRT), originating from the northern region of Fujian province, has a good reputation for its distinctive Yan flavor and floral–fruity aroma. The aroma quality, an essential element of the Yan flavor, undergoes various changes during the manufacturing process of WRT. To enhance the understanding of the formation patterns of WRT aroma and its influence on the flavor quality of WRT, we utilized both manufactured WRT (Rougui tea) and primary tea as materials. Utilizing a sensory evaluation, detection of volatile compounds, and multivariate statistical analysis, we identified and characterized the distinctive volatile components present in WRT. The sensory evaluation and radar chart analysis revealed that the primary tea exhibited a strong and lasting aroma, along with a mellow taste and a prominent Yan flavor. Through gas chromatography time-of-flight mass spectrometry (GC-TOF MS), a total of 251 volatile compounds were identified. The odor activity value (OAV) was calculated to identify key aroma-active compounds in the primary tea. The results indicated that a total of 14 compounds had an OAV greater than 1.0, including (2-nitroethyl) benzene, indole, and geranylacetone. These compounds exhibited floral and fruity aroma attributes. They primarily formed and accumulated during the latter stages of WRT. Using a partial least squares discrimination analysis (PLS-DA) combined with a variable importance in projection (VIP) score greater than 1.0 as a criterion, a total of 89 compounds were identified. Furthermore, out of the selected compounds, 15 types, including geraniol, 1-nonanol, and 1-butyl-2-ethyl-cyclopropene, were found to exclusively exist during the enzymatic manufacturing stages, particularly during the intermediate and later phases of the turn-over process (the last-three-times turn-over treatments), exhibiting predominantly floral and sweet fragrances. In contrast, during the non-enzymatic stages, only four compounds, such as pentanoic acid and phenylmethyl ester, were detected, exhibiting a fruity aroma profile. These volatile compounds significantly influenced the quality attributes of the final tea product, resulting in strong and lasting characteristics, particularly marked by a pronounced floral and fruity aroma. This study revealed how the aroma quality in WRT is developed and pinpointed possible volatile compounds that react to post-harvest treatments, thereby offering valuable insights relating to the intelligent production strategies of WRT. Full article

LBD transcription factors are critical regulators of plant growth and development. Recent studies highlighted their significant role in the transcriptional regulation of plant growth and metabolism. Thus, identifying the CeLBD gene in Cymbidium ensifolium, a species abundant in floral scent metabolites, could provide deeper insights into its functional significance. A total of 34 LBD genes were identified in C. ensifolium. These CeLBDs fell into two major groups: Class I and Class II. The Class I group contained 30 genes, while the Class II group included only 4 genes. Among the 30 Class I genes, several genes in the Ie branch exhibited structural variations or partial deletions (CeLBD20 and CeLBD21) in the coiled-coil motif (LX₆LX₃LX₆L). These changes may contribute to the difficulty in root hair formation in C. ensifolium. The variations may prevent normal transcription, leading to low or absent expression, which may explain the fleshy and corona-like root system of C. ensifolium without prominent lateral roots. The expansion for CeLBDs was largely due to special WGD events in orchids during evolution, or by segmental duplication and tandem duplication. CeLBDs in different branches exhibit similar functions and expression characteristics. Promoter analysis enriched environmental response elements, such as AP2/ERF, potentially mediating the specific expression of CeLBDs under different stresses. CeLBDs were predicted to interact with multiple transcription factors or ribosomal proteins, forming complex regulatory networks. CeLBD20 was localized in the cytoplasm, it may act as a signaling factor to activate other transcription factors. CeLBD6 in Class II was significantly up-regulated under cold, drought, and ABA treatments, suggesting its role in environmental responses. Furthermore, metabolic correlation analysis revealed that its expression was associated with the release of major aromatic compounds, such as MeJA. These findings offer valuable insights for further functional studies of CeLBD genes in C. ensifolium. Full article

Lilies (Lilium spp.) are renowned for their diverse and captivating floral scents, which are highly valued both commercially and ornamentally. This review provides a comprehensive overview of recent advancements in the identification, biosynthesis, and regulation of fragrance components in lily flowers. Various volatile organic compounds (VOCs) that contribute to the unique scents of different lily species and cultivars, including terpenoids, benzenoids/phenylpropanoids, and fatty acid derivatives, are discussed. The release patterns of these compounds from different floral tissues and at different developmental stages are examined, highlighting the significant role of tepals. Detection methods such as gas chromatography–mass spectrometry (GC-MS) and sensory analysis are evaluated for their effectiveness in fragrance research. Additionally, the biosynthetic pathways of key fragrance compounds are explored, focusing on the terpenoid and benzenoid/phenylpropanoid pathways and the regulatory mechanisms involving transcription factors and environmental factors. This review also addresses the influence of genetic and environmental factors on fragrance production and proposes future research directions to enhance the aromatic qualities of lilies through selective genetic and breeding approaches. Emphasis is placed on the potential applications of these findings in the floral industry to improve the commercial value and consumer appeal of lily flowers. Full article

Terpenes are critical components of the floral fragrance component in Dendrobium chrysotoxum, synthesized by terpene synthase (TPS). Analysis of the D. chrysotoxum genome and transcriptional data revealed that the gene DcTPSb1 was significantly up-regulated during flowering periods, showing a strong correlation with the accumulation of aromatic monoterpenes in the floral components of Dendrobium chrysotoxum. Consequently, the DcTPSb1 gene was selected for further analysis. DcTPSb1 exhibited elevated expression levels in flowers among four organs (roots, stems, leaves, flowers) of D. chrysotoxum, with the highest expression observed during the blooming phase, which aligned with the accumulation of volatile terpenes during flowering. DcTPSb1, located in the chloroplasts, was identified as a member of the TPS-b subfamily associated with monoterpenes synthesis, showing close phylogenetic relationships with homologous proteins in related plant species. An analysis of the promoter region of DcTPSb1 indicated that it may be regulated by methyl jasmonate (MeJA) responsiveness. Functionally, DcTPSb1 was shown to catalyze the conversion of geranyl diphosphate (GPP) to linalool, ocimene, and (-)-α-pinitol in vitro. Overexpression of DcTPSb1 in tobacco resulted in a significant increase in terpenoid release during the blooming stage; however, the up-regulated substances did not include their catalytic products. The classification of DcTPSb1 as a terpene synthase capable of producing multiple products provides valuable insights into the complex biosynthesis of terpenes in orchids. These findings enhance our understanding of the functional diversity of DcTPSb1 and the processes involved in terpene biosynthesis in orchids. Full article

This study utilized gas chromatography-mass spectrometry (GC-MS) to analyze the volatile components and sensory profiles of four basil varieties, both in their fresh state and as essential oils (EOs) extracted via steam distillation (SD). By employing headspace solid-phase microextraction (HS-SPME) and SD/GC-MS, a comprehensive comparison was conducted to elucidate the changes in volatile profiles before and after drying and extraction processes. In total, 47 volatile components were identified in fresh basil samples. Methyl chavicol was predominant in Thai basil (66.53%), lemon basil (90.18%), and sweet basil (89.19%), whereas linalool (58.56%) was the major component in purple basil. For EOs, 66 volatile components were detected, with methyl chavicol remaining significant in Thai basil (65.27%) and lemon basil (81.03%), though its proportion decreased in sweet basil (29.34%). Purple basil EOs showed a higher proportion of alcohols (54.54%) and terpenoids (31.31%), with the notable presence of linalool (20.08%) and τ-juniper alcohol (18.18%). Multivariate analyses, including principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA), revealed significant variations in volatile profiles among basil varieties. Sensory evaluation, supported by radar fingerprinting, demonstrated that the drying and extraction processes notably impacted the aroma profiles. Distinctive aroma profiles revealed that Thai basil was noted for its aniseed aroma, lemon basil for its lemon scent, sweet basil for its pungency, and purple basil for its floral notes. These findings highlight the diverse applications of basil varieties and their EOs, providing valuable insights into flavoring, fragrance, and therapeutic products based on their volatile compositions and sensory attributes. Full article