Scent Patterns Research Articles

Evaluation of a Commercial Electronic Nose Based on Carbon Nanotube Chemiresistors.

Recently a hand-held, carbon-nanotube-based electronic nose became available on the market. Such an electronic nose could be interesting for applications in the food industry, health monitoring, environmental monitoring, and security services. However, not much is known about the performance of such an electronic nose. In a series of measurements, the instrument was exposed to low ppm vapor concentrations of four volatile organic compounds with different scent profiles and polarities. Detection limits, linearity of response, repeatability, reproducibility, and scent patterns were determined. The results indicate detection limits in the range of 0.1-0.5 ppm and a linear signal response in the range of 0.5-8.0 ppm. The repeatability of the scent patterns at compound concentrations of 2 ppm allowed the identification of the tested volatiles based on their scent pattern. However, the reproducibility was not sufficient, since different scent profiles were produced on different measurement days. In addition, it was noted that the response of the instrument diminished over time (over several months) possibly by sensor poisoning. The latter two aspects limit the use of the current instrument and make future improvements necessary.

Analysis of Floral Scent and Volatile Profiles of Different Aster Species by E-nose and HS-SPME-GC-MS.

Plants from the Aster species are known to be a rich source of bioactive chemical compositions and are popularly known for their medicinal properties. To investigate the relationship between the nine species of Aster, the floral fragrance and volatile profile patterns were characterized using E-nose and HS-SPME-GC-MS. Initial optimization for fragrance analysis was performed with Aster yomena using E-nose by evaluating the scent patterns in different flowering stages. Aster yomena exhibited varied scent patterns in each flowering stage, with the highest relative aroma intensity (RAI) in the full flowering stage. PCA analysis to compare and analyze the scent characteristics of nine Aster species, showed a species-specific classification. HS-SPME-GC-MS analysis of flowers from nine Aster species revealed 52 volatile compounds including β-myrcene, α-phellandrene, D-limonene, trans-β-ocimene, caryophyllene, and β-cadinene. The terpenoid compounds accounted for the largest proportion. Among the nine Aster species flowers, Aster koraiensis had sesquiterpenes as the major component, and the remaining eight varieties had monoterpenes in abundance. These results could distinguish the species according to the scent patterns and volatile components of the nine Aster species. Additionally, flower extracts from the Aster species' plants exhibited radical scavenging antioxidant activity. Among them, it was confirmed that Aster pseudoglehnii, Aster maackii, and Aster arenarius had high antioxidant activity. In conclusion, the results of this study provide fundamental data of the volatile compound properties and antioxidant activity of Aster species, offering basic information of valuable natural sources that can be utilized in the pharmaceutical, perfume, and cosmetic industries.

Discrimination of Floral Scents in <i>Chrysanthemum morifolium</i> Cultivars using Electronic Nose

The aim of the present study was to investigate the differences in volatile profiles among different Korean chrysanthemum cultivars grown as cut flowers. To optimize a method for sampling and comparing scents, the scents were evaluated by electronic nose (E-nose) at different flowering stages and in different organs and cultivars. The values of maximum resistance changes of metal oxide semiconductor sensors and relative aroma intensity were highest at flowering stage III (full flower stage of ray florets and initial opening disc florets) among different stages and in disc florets among different floral organs of cut chrysanthemums. Among the 12 chrysanthemum cultivars, the highest values for response change and relative aroma intensity were observed in the flowers of the ‘Ilweol’ cultivar. To compare scent patterns among the cultivars, E-nose sensor data was subjected to multivariate statistical analysis. Principal component analysis and discriminant function analysis of the volatile metabolic profile data indicated that chrysanthemum samples were clearly discriminated in a cultivar-dependent manner. These results show that different cultivars are characterized by distinct volatile profiles. Hierarchical cluster analysis showed that the 12 chrysanthemum cultivars were separated into 3 main groups according to the relationship of volatile profiles; however, chrysanthemum cultivars were not clustered according to the flower shape. We propose that these results could be used as the basis on which to improve the breeding of cut chrysanthemums based on volatile characteristics.

누룩별 약주의 품질특성

Yakju is a traditional Korean beverage made from rice and Nuruk. In this study, the quality characteristics of Yakju by rice Nuruk and traditional Nuruk were examined. The alcohol content (%) of Yakju with A.luchuensis was 17.10-17.60, and Yakju with A.oryzae 17.40-18.00, which showed a slightly higher alcohol content (p＜0.05). The pH, amino acidity, volatile acid, and b value in Yakju with A.oryzae were significantly higher than A.luchuensis (p＜0.001). The acidity, L, a value of Yakju with A.luchuensis was significantly higher in Yakju with A.oryzae (p＜0.001). An analysis of the electronic nose of Yakju showed that the fragrance pattern of Yakju was 92.364% for the one ingredient and 7.545% for the two ingredient. The distinction by rice Nuruk was classified by the two ingredients, and when songhak was used along with traditional Nuruk, it had an aroma pattern independent of the other Yakju. According to the results of electronic tongue analysis, Yakju with A.luchuensis was found to be sour, umami, and Yakju with A.oryzae had a salty, bitter, and sweet taste. According to the sensory evaluation, taste was the most significant among the panel (p＜0.001), and the harmony of taste was the highest with Yakju with A.luchuensis. The general Nuruk and aroma patterns of Yakju are divided largely by rice Nuruk in the manufacture of Yakju. These results are expected to be great help in the development of new products for Yakju, considering the flavor and taste of Yakju.

Nocturnal floral scent profiles of Myrtaceae fruit crops

Communication between plants and nocturnal pollinators in low light conditions is mainly guided by floral scents, which is well documented for plants pollinated by bats, moths, and beetles. Just recently, nocturnal bees have been added to the list of pollinators known to respond to floral scents of their host plants. Little is known about the floral scent chemistry of plants visited and pollinated by nocturnal bees. Among these plants are economically important fruit crops of the family Myrtaceae. We aimed to analyze the nocturnal floral scent profiles of 10 species of Myrtaceae (only diurnal P. cattleianum was sampled after sunrise) and address the following questions: i) What are the main floral scent compounds emitted by the species? ii) Are the floral scent profiles similar to those described for other species pollinated by nocturnal bees? Floral scents were collected by dynamic headspace and analyzed by GC-MS (gas chromatography - mass spectrometry). The total amount of scent trapped ranged from 74 ng/flower/hour for Syzygium malaccense to 7556 ng/flower/hour for Eugenia dysenterica. A total of 46 floral scent compounds were detected in the samples with the most abundant compounds being the aromatics benzaldehyde, benzyl alcohol, 2-phenylethanol, methyl salicylate, 2-phenylethyl acetate, and benzyl acetate; the aliphatic compound 1-octanol; and the monoterpene linalool. The different species exhibited different relative scent patterns. Overall, the nocturnal scents of the studied species of Myrtaceae are dominated by aromatic compounds, which is in contrast to the scent profiles described for other plants pollinated by nocturnal bees.

Cross-modal transfer in visual and nonvisual cues in bumblebees

Bumblebees Bombus terrestris are good at learning to distinguish between patterned flowers. They can differentiate between flowers that differ only in their patterning of scent, surface texture, temperature, or electrostatic charge, in addition to visual patterns. As recently shown, bumblebees trained to discriminate between nonvisual scent patterns can transfer this learning to visually patterned flowers that show similar spatial patterning to the learnt scent patterns. Bumblebees can, therefore, transfer learnt patterns between different sensory modalities, without needing to relearn them. We used differential conditioning techniques to explore whether cross-modal transfer of learnt patterns also occurred between visual and temperature patterns. Bumblebees that successfully learnt to distinguish rewarding and unrewarding temperature patterns did not show any preferences for the corresponding unlearnt visual pattern. Similarly, bumblebees that learnt visual patterns did not transfer these to temperature patterns, suggesting that they are unable to transfer learning of temperature and visual patterns. We discuss how cross-modality pattern learning may be limited to modalities that have potentially strong neurological links, such as the previously demonstrated transfer between scent and visual patterns.

Incomplete synchrony of inflorescence scent and temperature patterns in Arum maculatum L. (Araceae)

In many Araceae both scent and heat production are known to temporally vary throughout anthesis, and in several species strong scents are released for pollinator attraction when thermogenesis is also strong. However, it is not known whether the temporal patterns of both scent emission and temperature are strictly synchronous and, for example, reach their maxima at the same time. We studied Arum maculatum, a brood-site deceptive species attracting its moth fly pollinators with strong fetid scents, to study temporal patterns in scent emission and temperature during anthesis. Inflorescence scents were collected and analysed by dynamic headspace and gas chromatography-mass spectrometry (GC-MS) or by proton-transfer-reaction-time-of-flight mass spectrometry (PTR-TOFMS), and the temperature of the appendix, which is the heating osmophore during pollinator attraction, was recorded by a thermocouple. We overall found that scent emission and temperature patterns were strongly correlated. However, in none of the seven studied individuals was the highest amount of scent released at times with the maximum temperature difference. Thus, patterns of scent emission and temperature are somewhat asynchronous suggesting that high scent emission rates and temporal scent patterns in plants with thermogenesis cannot be solely explained by temperature patterns. This calls for more in-depth studies to better understand the interplay between scent emission and thermogenesis.

Identification of Floral Fragrances and Analysis of Fragrance Patterns in Herbaceous Peony Cultivars

Thirty herbaceous peony (section Paeonia of the genus Paeonia) cultivars were divided into four groups (no fragrance, light fragrance, medium fragrance, or intense fragrance) based on their sensory evaluation scores. Using dynamic headspace sampling (DHS) and automatic thermal desorption–gas chromatography/mass spectrometry (ATD-GC/MS), 130 volatile organic components were detected in these 30 cultivars and a total of 72 compounds were identified as scent components. The main compounds were phenylethyl alcohol, β-caryophyllene, linalool, (R)-citronellol, and nerol. Selecting α-pinene as the standard, the volatile components of these cultivars were quantitatively analyzed. By combining the sensory evaluation scores and the results of quantitative analysis, we found that ‘Going Bananas’, ‘Cream Delight’, ‘Zhu Sha Pan’, ‘Qiao Ling’, ‘Duchess de Nemours’, and ‘Yang Fei Chu Yu’ displayed an intense fragrance and, thus, had relatively high commercial value for the flower fragrance industry. ‘Red Magic’, ‘Joker’, ‘Fairy Princess’, ‘Lovely Rose’, ‘Carina’, and ‘Etched Salmon’ were excluded from the hierarchical cluster of aromatic compounds and the analysis of fragrance patterns because of the low amount of fragrance they released and poor sensory evaluation results. Based on a cluster analysis, assessment of the major aromatic compounds, and the results of sensory evaluation, the remaining 24 cultivars were divided into five fragrance patterns for the first time: woody scent [cluster I (major fragrance β-caryophyllene)], fruity scent [cluster II (phenylethyl alcohol)], lily scent [cluster III (linalool)], rose scent {cluster IV [(R)-citronellol]}, and an orange blossom scent [cluster V (nerol)].

Bumblebees distinguish floral scent patterns, and can transfer these to corresponding visual patterns.

Flowers act as multisensory billboards to pollinators by using a range of sensory modalities such as visual patterns and scents. Different floral organs release differing compositions and quantities of the volatiles contributing to floral scent, suggesting that scent may be patterned within flowers. Early experiments suggested that pollinators can distinguish between the scents of differing floral regions, but little is known about how these potential scent patterns might influence pollinators. We show that bumblebees can learn different spatial patterns of the same scent, and that they are better at learning to distinguish between flowers when the scent pattern corresponds to a matching visual pattern. Surprisingly, once bees have learnt the spatial arrangement of a scent pattern, they subsequently prefer to visit novel unscented flowers that have an identical arrangement of visual marks, suggesting that multimodal floral signals may exploit the mechanisms by which learnt information is stored by the bee.

Diel pattern of floral scent emission matches the relative importance of diurnal and nocturnal pollinators in populations of Gymnadenia conopsea.

Floral scent is considered an integral component of pollination syndromes, and its composition and timing of emission are thus expected to match the main pollinator type and time of activity. While floral scent differences among plant species with different pollination systems can be striking, studies on intraspecific variation are sparse, which limits our understanding of the role of pollinators in driving scent divergence. Here, we used dynamic headspace sampling to quantify floral scent emission and composition during the day and at night in the natural habitat of six Scandinavian populations of the fragrant orchid Gymnadenia conopsea. We tested whether diel scent emission and composition match pollinator type by comparing four populations in southern Sweden, where nocturnal pollinators are more important for plant reproductive success than are diurnal pollinators, with two populations in central Norway, where the opposite is true. To determine to what extent scent patterns quantified in the field reflected plasticity, we also measured scent emission in a common growth chamber environment. Both scent composition and emission rates differed markedly between day and night, but only the latter varied significantly among populations. The increase in scent emission rate at night was considerably stronger in the Swedish populations compared with the Norwegian populations. These patterns persisted when plants were transferred to a common environment, suggesting a genetic underpinning of the scent variation. The results are consistent with a scenario where spatial variation in relative importance of nocturnal and diurnal pollinators has resulted in selection for different scent emission rhythms. Our study highlights the importance of adding a characterization of diel variation of scent emission rates to comparative studies of floral scent, which so far have often focused on scent composition only.

Floral scent and pollinators of Ceropegia trap flowers

Ceropegia L. (Apocynaceae, Asclepiadoideae) comprises more than 200 species, all characterized by complex pitfall flowers. The deceptive flowers are myiophilous and pollinated predominantly by small flies from different families. It has been suggested that floral scent cues, that mimic food sources or oviposition sites, play an important role for attraction of target fly pollinators, and, together with morphological flower traits, explain the high functional specialization in terms of pollination by specific taxa. However, apart from two Ceropegia species, the floral scent composition and the mimicry strategies in this genus are unexplored. We tested for associations between floral scent and insect visitor and pollinator assemblages of 14 Ceropegia species. We also used nrDNA and chloroplast DNA markers to calculate a Maximum Likelihood tree and test for phylogenetic signal in scent chemistry and flower visitors/pollinators. The observed pollinators belonged to eight fly families, at least 18 genera, and 33 morphospecies, but each Ceropegia species was typically associated with only one or two pollinating fly families or genera. We detected a total of 317 floral volatiles, including aliphatic and aromatic components, terpenes, and various unknowns. Both flower visitor and pollinator patterns did not show an overall association with floral scent chemistry. There was phylogenetic signal in flower visiting fly families and fly pollinator assemblages, but not in flower visiting fly morphospecies and overall scent chemistry. We discuss that despite the not existing correlation between pollinator and scent patterns the highly specific pollination system in Ceropegia will be explained mainly by floral scent chemistry.

Floral Scent Composition and Emission Patterns of Three Symplocos Species

The main floral scent compounds and the dynamic changes in the flower opening process of Symplocos decora, S. botryantha, and S. paniculata were analyzed by SPME and GC-MS techniques. The results showed that terpenes and alcohols are the main floral scent compounds in S. decora with purple color, whereas in S. decora with white color, there is considerable relative content of aldehydes and ketones except terpenes and alcohols. Aldehydes and alcohols are the main floral scent compounds in S. botryantha and S. paniculata. Among the major compounds, l-verbenone is the specific volatile compound in S. decora, while 2-ethylbutanal is the specific volatile compound in S. botryantha. Generally speaking, the varieties of floral scent compounds are increasing with the development of flower stages and attain the largest numbers at fullopening stage. The differences in the kinds of main floral scent compounds and the relative content of them may be the main reason for the fragrance difference among these three species.

Comparative analyses of flower scent inSileneaereveal a contrasting phylogenetic signal between night and day emissions

AbstractFlower scents are complex blends of volatile compounds often shaped by selection pressures exerted by mutualistic and antagonistic interaction partners, but also by phylogenetic constraints. So far, little is known about the relative effect of selection and phylogenetic signal on scent patterns, and no study to date analyzed the phylogenetic signal in multivariate semiquantitative scent patterns. We analyzed the phylogenetic signal in qualitative and semi‐quantitative patterns of flower scents in 47 Sileneae (Caryophyllaceae) species using phylogenetic principal component analysis (pPCA) and several indices of univariate and multivariate phylogenetic signal. As previous results showed that Sileneae species are visited by diurnal and nocturnal pollinators and flower scents also vary along the day, we compared the phylogenetic signal between night and day. MultivariatepPCAanalyses identified compounds that correlate with the phylogeny at both night and day; however, multivariate Bloomberg′s K detected phylogenetic signal in the dataset of night scents, but not of day scents. In multivariate qualitative datasets, phylogenetic signal was neither found for day nor for night scents. In univariate analyses, phylogenetic signal was detected for some compounds both for day and night scents. Overall, we found that the phylogenetic signal is stronger in night compared to day scents, which might be owed to the different guilds of pollinators at day and night. At day, the phylogenetic resemblance of Sileneae scents might be masked by or disappear due to divergent selective pressures exerted by a diverse guild of pollinators on the different species. In contrast, we hypothesize that the nocturnal moth pollinators exert similar selective pressures; thus, the phylogenetic similarity of scent profiles might be conserved. Future studies of scent phylogenetic signal must consider not only the usage of qualitative measures but also semiquantitative analyses.

Analysis of Floral Scent Patterns in Flowering Stages and Floral Organs of Maxillaria Using an Electronic Nose

The present study investigated the floral scent pattern and intensity of the floral organs in various species and cultivars of Maxillaria at different flowering stages using an electronic nose with 6 metal oxide sensors. The scents of species and cultivars showed various patterns overall, especially that of M. tenuifolia. The scent patterns of cultivars derived from M. variabillis formed a clustere that differed greatly from the origin M. variabillis. In M. tenuifolia, the scent pattern differed by stage, and was strongest at the initial flowering stage. Each floral organ showed different scent patterns; the sepal emitted the strong scent of all floral organs. This study establishes baseline data for the analysis scent of Maxillaria scents and for breeding aromatic orchids.

온주밀감 정유가 함유된 마이크로캡슐로 처리한 면 편성물의 향기 특성 -전자코 분석과 주관적 감각과의 관계를 중심으로-

This study was aimed at investigating the fragrance pattern of cotton knit treated with microcapsules containing Citrus Unshiu oil with respect to washing and rubbing frequencies, using electronic noise and relating it to human subjective sensation. From the results, we discovered that the microcapsule-treated knit with one and two repetitions of washing exhibited the strongest fragrance and the untreated knit exhibited fragrance intensity similar to that of a knit that had undergone 15 repetitions of washing. However, this pattern was not found to be significantly related to subjective sensation. When cotton knits subjected to repeated rubbings were tested using electronic nose analysis, the citrus fragrance appeared to strengthen till 10 repetitions of rubbing, and thereafter, it tended to weaken. This pattern was similar to that of human subjective sensations described as fragrant, sweet, pleasant, and strong. In particular, the first few scores of the discriminant function obtained using the electronic nose were revealed to be highly correlated with the subjective sensation descriptor fragrant. These results imply that the electronic nose could aid in the analysis of the fragrance of oil microcapsule-loaded fabrics by predicting subjective sensation and that 10 repetitions by a crockmeter could be used to maximize the fragrance intensity of capsule-treated fabric.

Floral fragrances of Hemerocallis L. (daylily) evaluated by headspace solid-phase microextraction with gas chromatography-mass spectrometry

ABSTRACTTraditional breeding objectives focusing on flower type and colour have resulted in the lack of floral fragrances in modern daylilies. Headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to determine the contributions of floral volatiles to floral fragrances in 46 daylilies (seven species, one variety, and 38 cultivars). Thirty-seven floral volatiles were identified, including 30 terpenoids, five benzenoids, and two nitrogenous compounds. Sensory evaluation and HS-SPME-GC-MS revealed that variations in the relative emission rates and proportions of (E)-β-ocimene and linalool were mainly responsible for different fragrance patterns in Hemerocallis. The studied daylilies were grouped to six fragrance patterns: (1) intense herbaceous and pungent scent, having the highest (E)-β-ocimene emission level; (2) intense flowery and pungent scent, having medium (E)-β-ocimene and low linalool emission levels; (3) medium flowery and sweet scent, having very low (E)-β-ocimene and the highest linalool emission levels; (4) low flowery and fresh scent, having low (E)-β-ocimene and no linalool emission levels; (5) very low herbaceous and fresh scent, having very low (E)-β-ocimene and linalool emission levels; and (6) no scent, having trace amounts of floral volatiles.

An Effective Quality Control of Pharmacologically Active Volatiles of Houttuynia cordata Thunb by Fast Gas Chromatography-Surface Acoustic Wave Sensor.

Fast gas chromatography-surface acoustic wave sensor (GC/SAW) has been applied for the detection of the pharmacological volatiles emanated from Houttuynia cordata Thunb which is from South Korea. H. cordata Thunb with unpleasant and fishy odors shows a variety of pharmacological activities such as anti-microbial, anti-inflammatory, anti-cancer, and insect repellent. The aim of this study is to show a novel quality control by GC/SAW methodology for the discrimination of the three different parts of the plant such as leaves, aerial stems, and underground stems for H. cordata Thunb. Sixteen compounds were identified. β-Myrcene, cis-ocimene and decanal are the dominant volatiles for leaves (71.0%) and aerial stems (50.1%). While, monoterpenes (74.6%) are the dominant volatiles for underground stems. 2-Undecanone (1.3%) and lauraldehyde (3.5%) were found to be the characteristic components for leaves. Each part of the plant has its own characteristic fragrance pattern owing to its individual chemical compositions. Moreover, its individual characteristic fragrance patterns are conducive to discrimination of the three different parts of the plant. Consequently, fast GC/SAW can be a useful analytical method for quality control of the different parts of the plant with pharmacological volatiles as it provides second unit analysis, a simple and fragrant pattern recognition.

Floral scent and its correlation with AFLP data in Sorbus

Comparisons between floral scent-based and DNA-molecular-based taxonomies are rare, yet such comparisons indicate that scent can provide useful taxonomic information. Here, we correlate the phytochemical differentiation in floral scent to the DNA-molecular-based differentiation in the genus Sorbus. Inflorescence scent patterns of the apomictic and endemic Sorbus latifolia microspecies Sorbus franconica, Sorbus adeana, and Sorbus cordigastensis originated by hybridization as well as their parental taxa Sorbus aria agg. and Sorbus torminalis were investigated with the dynamic headspace method. The scent data (presence/absence of compounds) were used to construct an UPGMA tree, to calculate a similarity matrix, and to correlate them with the published amplified fragment length polymorphism (AFLP) data of the same individuals, populations, and taxa. Flow cytometry was used to estimate the DNA-ploidy level of the taxa. Scent analyses showed a total of 68 substances, among them aromatic compounds, terpenoids, aliphatics, and nitrogen-containing compounds. The scent patterns were taxon-specific, and the number of scent components differed among taxa. The correlations with the published AFLP data on population and individual level are highly significant, indicating that the scent and AFLP data are highly congruent in the plants studied. Scent therefore provides useful taxonomic characters in Sorbus.

The role of preadaptations or evolutionary novelties for the evolution of sexually deceptive orchids.

The role of preadaptations or evolutionary novelties for the evolution of sexually deceptive orchids.

Development of a Small Sized Cymbidium Variety ‘Snow Bell’ with Light Pink Colored Flower and Frangrance

A Cymbidium variety 'Snow Bell' (C. kanran <TEX>${\times}$</TEX> C. Jack Frost) was developed at the National Institute of Horticultural & Herbal Science, Rural Development Administration in 2011. A cross between C. kanran with small-sized greenish colored flowers and C. Jack Frost with bright pink colored flowers, was conducted in 1999. Based on flower color, leaf shape, flower stalk, and vigor one line was selected. Evaluation and selection trials were conducted from 2006 to 2010. 'Snow Bell' has a light pink sepal (RHS, R56D), red lip (R56A) and a leaf length of 47.5 cm. The average number of flowers on each peduncle is 13.8 and the flower diameter is 6.2 cm. The characteristics of petals and sepals show some incurve and some spreading. 'Snow Bell' has a vigorous growth and a round flower. It has an adequate peduncle height of 50.7 cm compared with leaf length of 47.5 cm, and start blooming in December. In electronic nose analysis, the degree of fragrance between 'Snow Bell' and the C. kanran was similar and both of them showed strong scents, although they had different fragrance patterns.