Floral Aromatics of Ptelea: Chemical Identification and Human Response

Many members of the citrus family (Rutaceae) are valued for the aromatic compounds emitted by their flowers. Ptelea species are unusually cold-hardy members of the Rutaceae, but conflicting descriptions of the fragrance of their unisexual flowers may discourage the use of these trees. We analyzed floral volatiles and human response to these chemicals to test the hypothesis that the fragrance of staminate and pistillate flowers of these species differs. Gas chromatography and mass spectrometry showed that most volatile chemicals emitted by flowers of Ptelea trifoliata and Ptelea crenulata are monoterpenes, sesquiterpenes, and esters. Most volatiles were emitted from flowers of both sexes, but ethyl benzoate and estragole were emitted only from pistillate flowers. When concentrations of aromatics differed between sexes, they were higher for pistillate flowers, except for cis-3-hexenyl butanoate and an unidentified terpene. For P. crenulata and P. trifoliata, respectively, 81% and 77% of survey responses were from volunteers who liked the fragrance. Panelists most frequently described the scent of flowers of P. crenulata of both sexes with the words citrus, lime, and sweet. Panelists distinguished between pistillate and staminate flowers of P. trifoliata, describing the odor of pistillate flowers most frequently with the words damp-earthy, spicy, and sweet; staminate flowers were perceived as light, fresh, grassy, and pleasant. This work represents the first analysis of floral volatiles of P. crenulata and resolves conflicting prior reports regarding the floral fragrance of P. trifoliata. We conclude that differences among people rather than the sex of flowers account for conflicting prior reports of floral fragrance. The scents of flowers of P. crenulata and P. trifoliata appeal to most people and are horticultural assets of these trees.

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Drawing power of virtual crowds

Journal of The Royal Society Interface ◽

10.1098/rsif.2018.0335 ◽

2018 ◽

Vol 15 (145) ◽

pp. 20180335 ◽

Cited By ~ 4

Author(s):

Elham Mohammadi Jorjafki ◽

Brad J. Sagarin ◽

Sachit Butail

Keyword(s):

Virtual Environments ◽

Virtual Environment ◽

Human Response ◽

Stimulus Group ◽

Indoor Location ◽

Motion Models ◽

City Street ◽

Survey Responses ◽

Large Groups

In 1969, social psychologist Milgram and his colleagues conducted an experiment on a busy city street where passers-by witnessed a set of actors spontaneously looking up towards a building. The experiment showed that the crowd's propensity to mimic the actor's gaze increased with the number of actors that looked up. This form of behavioural contagion is found in many social organisms and is central to how information travels through large groups. With the advancement of virtual reality and its continued application towards understanding human response to crowd behaviour, it remains to be verified if behavioural contagion occurs in walkable virtual environments, and how it compares with results from real-world experiments. In this study, we adapt Milgram's experiment for virtual environments and use it to reproduce behavioural contagion. Specifically, we construct a replica of an indoor location and combine two established pedestrian motion models to create an interactive crowd of 60 virtual characters that walk through the indoor location. The stimulus group comprised a subset of the characters who look up at a random time as the participants explore the virtual environment. Our results show that the probability of looking up by a participant is dependent on the size of the stimulus group saturating to near certainty when three or more characters look up. The role of stimulus size was also evident when participant actions were compared with survey responses which showed that more participants selected to not look up even though they saw characters redirect their gaze upwards when the size of the stimulus group was small. Participants also spent more time looking up and exhibited frequent head turns with a larger stimulus group. Results from this study provide evidence that behavioural contagion can be triggered in the virtual environment, and can be used to build and test complex hypotheses for understanding human behaviour in a variety of crowd scenarios.

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Emission and Regulation of Volatile Chemicals from Globe Amaranth Flowers

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.136.1.16 ◽

2011 ◽

Vol 136 (1) ◽

pp. 16-22 ◽

Cited By ~ 4

Author(s):

Yifan Jiang ◽

Nan Zhao ◽

Fei Wang ◽

Feng Chen

Keyword(s):

Las Vegas ◽

Gas Chromatography Mass Spectrometry ◽

Floral Volatiles ◽

Emission Pattern ◽

Volatile Chemicals ◽

Volatile Emission ◽

Gomphrena Globosa ◽

Ethylene Inhibitor ◽

Floral Volatile

Volatile chemicals emitted from the flowers of globe amaranth (Gomphrena globosa) were collected using a dynamic headspace technique and analyzed using gas chromatography–mass spectrometry. Among the four globe amaranth cultivars analyzed, Fireworks was the highest producer of floral volatiles. The flowers of the other three cultivars, Las Vegas White, Las Vegas Pink, and Las Vegas Purple, emit less volatiles, both qualitatively and quantitatively, than ‘Fireworks’. ‘Fireworks’ was chosen for detailed characterization of regulation of floral volatile emission. A diurnal pattern of emission of floral volatiles was observed from the flowers of ‘Fireworks’. In addition, the emission pattern was not significantly affected by light, suggesting that the circadian clock plays a major role in the regulation of volatile emission. The emission of floral volatiles from ‘Fireworks’ flowers that were treated with several chemicals was also analyzed. The treatment with silver thiosulphate, an ethylene inhibitor, led to enhanced emission of total volatiles. In contrast, the treatments with salicylic acid and jasmonic acid led to enhanced emission of total floral volatiles at 4 h but reduced emission at 24 h after the treatment. Biochemical pathways leading to the production of the major floral volatiles of globe amaranth are proposed and partly validated by cluster analysis of floral volatiles emitted from ‘Fireworks’ flowers under various conditions. The implications of the results of this study to the understanding of the reproductive biology of globe amaranth and the breeding of novel globe amaranth cultivars are discussed.

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Floral Scent in Wisteria: Chemical Composition, Emission Pattern, and Regulation

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.136.5.307 ◽

2011 ◽

Vol 136 (5) ◽

pp. 307-314 ◽

Cited By ~ 9

Author(s):

Yifan Jiang ◽

Xinlu Chen ◽

Hong Lin ◽

Fei Wang ◽

Feng Chen

Keyword(s):

Salicylic Acid ◽

Jasmonic Acid ◽

Floral Scent ◽

Gas Chromatography Mass Spectrometry ◽

Floral Volatiles ◽

Rhythmic Pattern ◽

Silver Thiosulphate ◽

Volatile Chemicals ◽

Volatile Emission ◽

Floral Volatile

Volatile chemicals emitted from the flowers of chinese wisteria (Wisteria sinenesis) and japanese wisteria (W. floribunda) were collected using a dynamic headspace technique and identified using gas chromatography–mass spectrometry; 28 and 22 compounds were detected from chinese wisteria and japanese wisteria flowers, respectively. These chemicals can be classified into four major classes, including fatty acid derivatives, benzenoids/phenylpropanoids, terpenoids, and nitrogen-containing compounds. Two monoterpenes, (E)-β-ocimene and linalool, belonging to the class of terpenoids, were the most abundant compounds emitted from both species. Despite strong similarity, the floral volatile profiles of the two species displayed variations in both quality and quantity. Chinese wisteria was selected as a model for further study of volatile emission from different parts of flowers, emission dynamics, and regulation of floral scent production. Although floral volatiles were detected from all flower parts, petals emitted the most. The emission of floral volatiles displayed a diurnal pattern with the maximal emissions occurring during the daytime. This rhythmic pattern was determined to be light-dependent. Regulation of floral volatile emission by exogenous chemicals, including silver thiosulphate (an ethylene inhibitor), salicylic acid, and jasmonic acid, also was analyzed. Generally, jasmonic acid promoted the emission of floral volatiles. In contrast, neither silver thiosulphate nor salicylic acid showed a significant effect on floral volatile emission. The results presented in this article suggest that wisteria can serve as a useful system for exploring novel biochemistry of floral scent biosynthesis. They also build a foundation for the study of the biological/ecological significance of floral volatiles on the reproductive biology of wisteria species.

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Composition and Emission Rhythm of Floral Scent Volatiles from Eight Lily Cut Flowers

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.137.6.376 ◽

2012 ◽

Vol 137 (6) ◽

pp. 376-382 ◽

Cited By ~ 27

Author(s):

Ying Kong ◽

Ming Sun ◽

Hui-tang Pan ◽

Qi-xiang Zhang

Keyword(s):

Mass Spectrometry ◽

Volatile Compounds ◽

Floral Scent ◽

Neutral Red ◽

Ethyl Benzoate ◽

Gas Chromatography Mass Spectrometry ◽

Floral Volatiles ◽

Cut Flowers ◽

Floral Scents ◽

Direct Thermal Desorption

Floral scents emitted from eight cultivars of cut lily flowers (Lilium) were analyzed. Floral volatiles were collected by headspace adsorption on sorbent tubes and analyzed by gas chromatography–mass spectrometry (GC/MS) using a direct thermal desorption. Fifty volatile compounds were identified. Nine compounds were detected in all lilies, whereas 20 compounds were detected in all scented lilies. The results revealed that non-scented lilies emitted trace amounts of volatile compounds, whereas scented lilies emitted high levels of volatile compounds. Monoterpenoids and benzenoids were the dominant compound classes of volatiles emitted from scented lilies. Myrcene, (E)-β-ocimene, linalool, methyl benzoate, and ethyl benzoate were the major compounds of the aroma of scented lilies; 1,8-cineole was also a major compound in the two scented oriental × trumpet hybrid lilies. Scent emissions occurred in a circadian rhythm with higher levels of volatiles emitted during the night. Lilium ‘Siberia’ was selected as a model to investigate the source of the emissions. GC/MS analysis of four flower parts and neutral red staining revealed that tepals were the source of floral scent.

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A General Method for Spectrometer Design in the Scoff Approximation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100092657 ◽

1976 ◽

Vol 34 ◽

pp. 538-539

Author(s):

J. R. Fields

Keyword(s):

Electron Microscope ◽

Transmission Electron Microscope ◽

Energy Analysis ◽

Incident Beam ◽

Scanning Transmission Electron Microscope ◽

Chemical Identification ◽

Scanning Transmission Electron ◽

Transmission Electron ◽

Scanning Transmission ◽

General Method

The energy analysis of electrons scattered by a specimen in a scanning transmission electron microscope can improve contrast as well as aid in chemical identification. In so far as energy analysis is useful, one would like to be able to design a spectrometer which is tailored to his particular needs. In our own case, we require a spectrometer which will accept a parallel incident beam and which will focus the electrons in both the median and perpendicular planes. In addition, since we intend to follow the spectrometer by a detector array rather than a single energy selecting slit, we need as great a dispersion as possible. Therefore, we would like to follow our spectrometer by a magnifying lens. Consequently, the line along which electrons of varying energy are dispersed must be normal to the direction of the central ray at the spectrometer exit.

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