Scent Emission Research Articles

Diurnal regulation of scent emission in rose flowers

Previous studies have shown diurnal oscillation of scent emission in rose flowers with a peak during the day (Helsper in Planta 207:88-95, 1998; Picone in Planta 219:468-478, 2004). Here, we studied the regulation of scent production and emission in Rosa hybrida cv. Fragrant Cloud during the daily cycle and focused on two terpenoid compounds, germacrene D and geranyl acetate, whose biosynthetic genes have been characterized by us previously. The emission of geranyl acetate oscillated during the daily light/dark cycle with a peak early in the light period. A similar daily fluctuation was found in the endogenous level of this compound and in the expression of its biosynthetic gene, alcohol acetyl transferase (RhAAT). The rhythmic expression of RhAAT continued under conditions of constant light or darkness, indicating regulation by the endogenous circadian clock. However, the accumulation and emission of geranyl acetate ceased under continuous light. Our results suggest that geranyl acetate production is limited by the level of its substrate geraniol, which is suppressed under constant light conditions. The emission of germacrene D also oscillated during the daily cycle with a peak early in the light period. However, the endogenous level of this compound and the expression of its biosynthetic gene germacrene D synthase (RhGDS) were constant throughout the day. The diurnal oscillation of germacrene D emission ceased under continuous light, suggesting direct regulation by light. Our results demonstrate the complexity of the diurnal regulation of scent emission: although the daily emission of most scent compounds is synchronized, various independently evolved mechanisms control the production, accumulation and release of different volatiles.

Regulation of simultaneous synthesis of floral scent terpenoids by the 1,8-cineole synthase of Nicotiana suaveolens

The white flowers of N. suaveolens emit a complex bouquet of fragrance volatiles. The dominant compounds are benzenoids (e.g. methyl benzoate, methyl salicylate, benzyl benzoate and benzyl salicylate), monoterpenes (1,8-cineole, limonene, sabinene, E-beta-ocimene, beta-beta-myrcene, alpha- and beta-pinene and alpha-terpineole) and sesquiterpenes (e.g. caryophyllene), which are all emitted at higher levels during the night. Here, we show that the simultaneous nocturnal emission of most monoterpenes is realized by a single floral-specific multi-product enzyme (1,8-cineole synthase, CIN), which synthesizes the monoterpenes of the "cineole cassette". Interestingly, N. suaveolens is the only known taxon of the Suaveolentes section to have a flower emitting "cineole cassette of monoterpenes" which is otherwise typical for the Alatae section. Gene sequence analysis of CIN has revealed the highest similarities to other angiosperm monoterpene synthases from Vitis vinifera, Quercus ilex, Citrus unshiu and C. limon, which cluster in the same branch of the terpene synthase B subfamily. However, based on its synthesized products, N. suaveolens CIN shares similarity with enzymes of the Arabidopsis thaliana root and Salvia officinalis leaf. The N. suaveolens CIN gene is only expressed in the stigma/style tissue and petals. Thin sections of petals present the enzyme primarily in the adaxial and abaxial epidermis; this facilitates the comprehensive emission of volatiles in all spacial directions. The oscillation of monoterpene emission is a consequence of the regulation of the CIN gene by the circadian clock, with oscillations occurring at the level of transcript and protein accumulations and of enzyme activity. Light/dark or dark/light transition signals synchronize the slow-running endogenous clock. Two strategies for synchronized scent emission have been established in N. suaveolens flowers: (i) the synthesis of volatile organic compounds by a multi-product enzyme and (ii) the coordination of biosynthetic pathways by a circadian clock.

The Challenge of Attracting Pollinators While Evading Floral Herbivores: Patterns of Fragrance Emission inCirsium arvenseandCirsium repandum(Asteraceae)

By increasing floral apparency to promote fertilization, plants risk attracting herbivores with the same signals that they use to lure pollinators. We hypothesized that fragrance is emitted in patterns that correspond to pollinators, with high emissions during periods of pollinator activity and low emissions otherwise, especially during periods of peak floral herbivore activity. Using a combination of analytical chemistry and field observations, we examined both the diel and ontogenetic patterns of fragrance in two Cirsium species, in relation to visitation patterns of pollinators and florivores. Emission rates were highest at reproductive maturity, when insect visitation by both pollinators and florivores was also highest. In Cirsium arvense, the diel pattern of fragrance emission matched patterns of pollinator activity and was lowest when florivores were active. In contrast, scent in Cirsium repandum peaked at midday rather than with insect activity; neither species had a diel pattern that followed ambi...

FLORAL BIOLOGY OF NORTH AMERICAN OENOTHERA SECT. LAVAUXIA (ONAGRACEAE): ADVERTISEMENTS, REWARDS, AND EXTREME VARIATION IN FLORAL DEPTH1,2

We studied the floral biology of five North American members of Oenothera L. sect. Lavauxia (Spach) Endl. (Onagraceae L.) in field and common greenhouse settings. Oenothera sect. Lavauxia floral morphology ranges from small, cleistogamous flowers (O. flava subsp. flava (A. Nels.) Garrett in Garrett) to some of the longest-tubed flowers in North America (O. flava subsp. taraxacoides (Wooton & Standl.) W. L. Wagner). Our goal was to compare qualitative and quantitative aspects of floral advertisement and reward among taxa in section Lavauxia. All taxa are night-blooming and self-compatible, have yellow petals with ultraviolet reflectance, and produce floral scents dominated by nitrogenous compounds and monoterpenes. Methyl nicotinate is present in the fragrances of all taxa of section Lavauxia regardless of flower size or putative mating system. Because this floral volatile is largely absent from other Oenothera species, we hypothesize that it is a synapomorphy for section Lavauxia. The rare O. acutissima W. L. Wagner, which is endemic to the Uintah Mountains, is polymorphic for odors dominated by linalool- or ocimene-derived compounds. Field observations in its type locality in northeastern Utah, U.S.A., revealed frequent floral visitation by crepuscular hawkmoths during the first 1.5 hours after anthesis, a pattern common to O. flava subsp. taraxacoides and other large-flowered Oenothera throughout western North America. Quantitative aspects of floral advertisement (flower size, scent emission) and reward (nectar volume) are dramatically reduced in putatively autogamous taxa (O. flava subsp. flava, O. triloba Nutt.), whereas qualitative aspects (flower color, scent, and nectar chemistry) remain comparable. All taxa could be distinguished through ordination of characters related to flower size, herkogamy, and scent chemistry. Extreme nectar tube length variation across the range of O. flava renders this an excellent model system for measuring the costs and mechanisms of shifts between outcrossing and autogamy.

Flower color–flower scent associations in polymorphic Hesperis matronalis (Brassicaceae)

Floral scent emission rate and composition of purple and white flower color morphs of Hesperis matronalis (Brassicaceae) were determined for two populations and, for each, at two times of day using dynamic headspace collection and GC–MS. The floral volatile compounds identified for this species fell into two main categories, terpenoids and aromatics. Principal component analysis of 30 compounds demonstrated that both color morphs emitted more scent at dusk than at dawn. Color morphs varied in chemical composition of scent, but this differed between populations. The white morphs exhibited significant differences between populations, while the purple morphs did not. In the white morphs, one population contains color–scent associations that match expectations from classical pollination syndrome theory, where the flowers have aromatic scents, which are expected to maximize night-flying moth pollinator attraction; in the second population, white morphs were strongly associated with terpenoid compounds. The potential impact that pollinators, conserved biosynthetic pathways, and the genetics of small colonizing populations may have in determining population-specific associations between floral color and floral scent are discussed.

Floral Scent Emission and Pollination Syndromes: Evolutionary Changes from Food to Sexual Deception

The Australian orchid genus Caladenia is unusual in comprising species that have evolved different pollination syndromes, including food deception and sexual deception. In this study, we compare the scent emission of Caladenia longicauda Lindl. (food deceptive), Caladenia arenicola Hopper & A. P. Br. (sexually deceptive), and their putative F1 hybrids to investigate floral scent emission and its changes with the evolution of pollination syndromes. Floral scent was collected with headspace sorption. Odor compounds were identified with gas chromatography–mass spectrometry and quantitative differences analyzed with gas chromatography. Using floral volatiles, the two species could clearly be separated according to their scent profile, with hybrids occupying an intermediate position. The scent profile of the food‐deceptive C. longicauda was dominated by benzenoids and isoprenoids, whereas in the sexually deceptive C. arenicola, benzenoids were reduced but fatty acid derivatives elevated. Caladenia longicauda e...

Postpollination Changes in Floral Odor in Silene latifolia: Adaptive Mechanisms for Seed-Predator Avoidance?

Floral odor is a key trait for pollinator attraction in many plants, but may also direct antagonists like herbivores to flowers. In this study, we examined how floral scent changes after pollination in Silene latifolia, which has a specialized relationship with the seed predator Hadena bicruris. We found an overall decrease in total scent emission and considerable changes in relative amounts of scent compounds after pollination. Lilac aldehydes A and B as well as veratrole contributed most to the decrease in scent emission. These three compounds are known to be key signals for the attraction of H. bicruris to the flowers. A specific downregulation of these compounds may increase the reproductive success of the plant by reducing seed predation after pollination.

The Effect Of Pollination On Floral Fragrance in Thistles

We investigated postpollination changes in fragrance composition and emission rates, as well as pollinator discrimination in hand-pollinated flower heads of two thistle species: Canada thistle (Cirsium arvense) and sandhill thistle (C. repandum). Following pollination, neither species emitted any novel compounds that could function as repellents. Scent emission rates declined in pollinated plants of both species by approximately 89% within 48 hr. This decline was evident in all 13 scent components of C. arvense. Apis mellifera, the dominant pollinator in the study population of C. arvense, was nearly three times more likely to visit an unpollinated rather than a pollinated flower head. A more complex pattern was observed for C. repandum, whose scent comprised 42 compounds. Quantities of aromatic and sesquiterpenoid volatiles declined after pollination, whereas two classes of scent compounds, fatty acid derivatives and monoterperpenoids, continued to be emitted. In C. repandum, discrimination against pollinated flower heads by Papilio palamedes (its primary pollinator) was not as marked. Unpollinated control plants of both species maintained moderate levels of scent production throughout this experiment, demonstrating that senescence and floral advertisement may be delayed until pollination has occurred. We expect postpollination changes in floral scent contribute to communication between plants with generalized pollinator spectra and their floral visitors. This study provides the first field study of such a phenomenon outside of orchids.

Emission Mechanism of Floral Scent inPetunia axillaris

The mechanism of floral scent emission was studied in Petunia axillaris, a plant with a diurnal rhythm of scent output. The emission rate of each volatile compound oscillated in synchrony with its endogenous concentration, so that the intensity of the floral scent appeared to be determined by the endogenous concentrations. The composition of major volatiles in the flower tissue and the flower headspace showed characteristic differences. A negative correlation was found between the boiling points of the volatile compounds and the ratio of their emitted and endogenous concentrations, indicating that the composition of the floral scent depends directly on the endogenous composition of the volatile compounds. We conclude that in P. axillaris, the physiological regulation of floral scent emission operates not in the vaporization process but in the control of the endogenous concentrations of volatiles through biosynthesis and metabolic conversion.

Floral scent emission and pollinator attraction in two species of Gymnadenia (Orchidaceae)

We investigated scent composition and pollinator attraction in two closely related orchids, Gymnadenia conopsea (L.) R.Br. s.l. and Gymnadenia odoratissima (L.) Rich. in four populations during the day and night. We collected pollinators of both species using hand nets and sampled floral odour by headspace sorption. We analysed the samples by gas chromatography with mass spectrometry to identify compounds and with electroantennographic detection to identify compounds with physiological activity in pollinators. In order to evaluate the attractiveness of the physiologically active compounds, we carried out trapping experiments in the field with single active odour substances and mixtures thereof. By collecting insects from flowers, we caught eight pollinators of G. conopsea, which were members of four Lepidoptera families, and 37 pollinators of G. odoratissima, from five Lepidopteran families. There was no overlap in pollinator species caught from the two orchids using nets. In the scent analyses, we identified 45 volatiles in G. conopsea of which three (benzyl acetate, eugenol, benzyl benzoate) were physiologically active. In G. odoratissima, 44 volatiles were identified, of which seven were physiologically active (benzaldehyde, phenylacetaldehyde, benzyl acetate, 1-phenyl-2,3-butandione, phenylethyl acetate, eugenol, and one unknown compound). In field bioassays using a mixture of the active G. odoratissima compounds and phenylacetaldehyde alone we caught a total of 25 moths, some of which carried Gymnadenia pollinia. A blend of the active G. conopsea volatiles placed in the G. odoratissima population did not attract any pollinators. The two orchids emitted different odour bouquets during the day and night, but G. odoratissima showed greater temporal differences in odour composition, with phenylacetaldehyde showing a significant increase during the night. The species differed considerably in floral odour emission and this differentiation was stronger in the active than non-active compounds. This differentiation of the two species, especially in the emission of active compounds, appears to have evolved under selection for attraction of different suites of Lepidopteran pollinators.

Emission of 2-phenylethanol from its β- d-glucopyranoside and the biogenesis of these compounds from [ 2H 8] l-phenylalanine in rose flowers

The hydrolysis of 2-phenylethyl β- d-glucopyranoside ( 3 ) was found to be partially inhibited by feeding with 2-phenyl- N-glucosyl-acetamidiumbromide ( 8 ), a β-glucosidase inhibitor, resulting in a decrease in the diurnal emission of 2-phenylethanol ( 2 ) from Rosa damascena Mill. flowers. Detection of [1,1,2,2′,3′,4′,5′,6′- 2H 8]- 2 and [1,2,2′,3′,4′,5′,6′- 2H 7]- 2 from R. ‘Hoh-Jun’ flowers fed with [1,1,2,2′,3′,4′,5′,6′- 2H 8]- 3 suggested that β-glucosidase, alcohol dehydrogenase, and reductase might be involved in scent emission. Comprehensive GC-SIM analyses revealed that [1,2,2,2′,3′,4′,5′,6′- 2H 8]- 2 and [1,2,2,2′,3′,4′,5′,6′- 2H 8]- 3 must be biosynthesized from [1,2,2,2′,3′,4′,5′6′- 2H 8] l-phenylalanine ( [ 2H 8]- 1 ) with a retention of the deuterium atom at α-position of [ 2H 8]- 1 .

Effect of feeding of 2‐phenylethyl glucopyranoside on the scent emission of cut flowers

AbstractThe floral notes of two types of cut flowers, rose (Rote rose) and baby's breath (Gypsophilia elegans), were dramatically changed when the cut stems were immersed in a vase solution containing 2‐phenylethyl β‐d‐glucopyranoside (PEBG). In a comparison between an untreated control R. rose and a treated R. rose placed in a vase solution containing 0.5% PEBG, approximately 500 times more 2‐phenylethyl alcohol was detected from the floret of the latter. In a similar comparison using G. elegans, the headspace of the treated flower not only had increased levels of 2‐phenylethyl alcohol but also had decreased levels of isovaleric acid and 2‐methyl butyric acid, the main malodorous components of the flower. These results suggested, first, that PEBG is useful as a fragrance enhancer for cut flowers, and second, that it may play a role in the fragrance formation of glycoside flowers. Copyright © 2003 John Wiley & Sons, Ltd.

Regulation of methylbenzoate emission after pollination in snapdragon and petunia flowers.

The molecular mechanisms responsible for postpollination changes in floral scent emission were investigated in snapdragon cv Maryland True Pink and petunia cv Mitchell flowers using a volatile ester, methylbenzoate, one of the major scent compounds emitted by these flowers, as an example. In both species, a 70 to 75% pollination-induced decrease in methylbenzoate emission begins only after pollen tubes reach the ovary, a process that takes between 35 and 40 h in snapdragon and approximately 32 h in petunia. This postpollination decrease in emission is not triggered by pollen deposition on the stigma. Petunia and snapdragon both synthesize methylbenzoate from benzoic acid and S-adenosyl-l-methionine (SAM); however, they use different mechanisms to downregulate its production after pollination. In petunia, expression of the gene responsible for methylbenzoate synthesis is suppressed by ethylene. In snapdragon, the decrease in methylbenzoate emission is the result of a decrease in both S-adenosyl-l-methionine:benzoic acid carboxyl methyltransferase (BAMT) activity and the ratio of SAM to S-adenosyl-l-homocysteine ("methylation index") after pollination, although the BAMT gene also is sensitive to ethylene.

ROSE FRAGRANCE: GENOMIC APPROACHES AND METABOLIC ENGINEERING

For centuries, rose (Rosa hybrida) has been the most important crop in the floriculture industry. Rose petals represent a unique system for studies of a wide range of highly important topics, such as the biosynthesis of secondary metabolites, including scent compounds and pigments, as well as developmental processes. Advances in genomics have made it possible to integrate entire genetic programs responsible for key processes, instead of focusing on individual phenomena via reductionist approaches. To this end, we generated cDNA libraries of rose petals to develop ESTs (expressed sequence tags). About 3000 ESTs have already been sequenced and catalogued. DNA chips were prepared and, using microarray analyses, numerous ESTs whose expression coincide with fragrance production were identified. To complement the genomic data, proteomic protocols for rose petals were developed: ca. 1000 proteins were mapped and their expression pattern during petal development characterized. Sequence information on ca. 100 of these proteins was also generated. In parallel, chemical and biological patterns of scent production and emission were determined and characterized by gas chromatography-mass spectrometry in petals of ca. 20 rose varieties. From these combined results, we identified several novel genes with putative function in numerous important processes, including fragrance production. For some of these the function was proven using Escherichia coli expression assay and/or transgenic plants. Furthermore, we have already generated transgenic flowers with either enhanced scent or novel fragrance composition.

Volatile ester formation in roses. Identification of an acetyl-coenzyme A. Geraniol/Citronellol acetyltransferase in developing rose petals.

The aroma of roses (Rosa hybrida) is due to more than 400 volatile compounds including terpenes, esters, and phenolic derivatives. 2-Phenylethyl acetate, cis-3-hexenyl acetate, geranyl acetate, and citronellyl acetate were identified as the main volatile esters emitted by the flowers of the scented rose var. "Fragrant Cloud." Cell-free extracts of petals acetylated several alcohols, utilizing acetyl-coenzyme A, to produce the corresponding acetate esters. Screening for genes similar to known plant alcohol acetyltransferases in a rose expressed sequence tag database yielded a cDNA (RhAAT1) encoding a protein with high similarity to several members of the BAHD family of acyltransferases. This cDNA was functionally expressed in Escherichia coli, and its gene product displayed acetyl-coenzyme A:geraniol acetyltransferase enzymatic activity in vitro. The RhAAT1 protein accepted other alcohols such as citronellol and 1-octanol as substrates, but 2-phenylethyl alcohol and cis-3-hexen-1-ol were poor substrates, suggesting that additional acetyltransferases are present in rose petals. The RhAAT1 protein is a polypeptide of 458 amino acids, with a calculated molecular mass of 51.8 kD, pI of 5.45, and is active as a monomer. The RhAAT1 gene was expressed exclusively in floral tissue with maximum transcript levels occurring at stage 4 of flower development, where scent emission is at its peak.

Evening specific oscillations of scent emission, SAMT enzyme activity, and SAMT mRNA in flowers of Stephanotis floribunda

Summary Stephanotis floribunda (Asclepediaceae), a plant that grows in Madagascar and is now a common house plant, emits a number of volatiles from its flowers. Its floral scent has been noted to increase in intensity during the night. At this time prominent scent compounds include benzyl alcohol, benzyl acetate, benzyl benzoate, eugenol, α-farnesene, linalool, linalool oxide, methyl benzoate (MBA), methyl salicylate (MSA), β-ocimene, phenylethyl alcohol, and 1-nitro-2-phenylethane. To investigate the level(s) at which the variation in fragrance emission is controlled, we isolated a gene encoding the enzyme salicylic acid carboxyl methyltransferase (SAMT), which catalyses the synthesis of methyl salicylate from salicylic acid and S-adenosyl-L-methionine. The expression of SAMT is petal-specific and developmentally regulated. Under light/dark conditions, SAMT mRNA levels and SAMT enzyme activities oscillate and reach the maxima in the first half of the night. These patterns correlate well with the emission of MSA. We conclude that the daily fluctuation in emission of MSA in S. floribunda likely involves de novo volatile synthesis resulting from time-regulated SAMT mRNA accumulation and SAMT enzyme activity.

Bumblebee Foraging Responses to Variation in Floral Scent and Color in Snapdragons (Antirrhinum: Scrophulariaceae)

We examined the roles of floral scent and color in attracting bumblebees (Bombus spp.) to snapdragon flowers (Antirrhinum, Sonnet cultivar). Corolla color differences covaried with differences in floral scent emissions in two inbred lines of snapdragon. White-flowered plants emitted methyl cinnamate, a scent compound not produced by yellow flowered plants, but lacked methyl benzoate, one of the major floral volatiles of the yellow-flowered line. Qualitative scent differences between the two lines were eliminated by applying the complementary scent compounds to filter paper wicks placed within the corollas. Laboratory analyses were performed using gas chromatography-mass spectrometry to verify appropriate modification of floral scents by this method. Two randomized arrays of control and scent-augmented flowers were visited by freely-foraging bumblebees in subalpine meadows in Colorado. Overall, yellow-flowered plants received more pollinator visits and had more flowers foraged per plant visit than did white-flowered plants. The addition of sweet-smelling methyl benzoate or spicy methyl cinnamate neither stimulated nor deterred bumblebee visits to either flower color.

Inverse single-strand RACE: an adapter-independent method of 5' RACE.

BioTechniquesVol. 27, No. 4 BenchmarksOpen AccessInverse Single-Strand RACE: An Adapter-Independent Method of 5′RACEYoram Eyal, Hanna Neumann, Etti Or & Ahuva FrydmanYoram Eyal*Address correspondence to Dr. Yoram Eyal, Department of Fruit Tree Breeding and Molecular Genetics, The Volcani Center—ARO, P.O. Box 6, Bet-Dagan, 50250, Israel. Internet: E-mail Address: eyalab@ias.agri.gov.ilThe Volcani Center—ARO, Bet-Dagan, IsraelSearch for more papers by this author, Hanna NeumannThe Volcani Center—ARO, Bet-Dagan, IsraelSearch for more papers by this author, Etti OrThe Volcani Center—ARO, Bet-Dagan, IsraelSearch for more papers by this author & Ahuva FrydmanThe Volcani Center—ARO, Bet-Dagan, IsraelSearch for more papers by this authorPublished Online:22 Aug 2018https://doi.org/10.2144/99274bm04AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinkedInRedditEmail "Inverse Single-Strand RACE: An Adapter-Independent Method of 5′RACE." , 27(4), pp. 656–658FiguresReferencesRelatedDetailsCited ByTwo Isoforms of the RNA Binding Protein, Coding Region Determinant-binding Protein (CRD-BP/IGF2BP1), Are Expressed in Breast Epithelium and Support Clonogenic Growth of Breast Tumor CellsJournal of Biological Chemistry, Vol. 290, No. 21The molecular and enzymatic basis of bitter/non-bitter flavor of citrus fruit: evolution of branch-forming rhamnosyltransferases under domestication8 November 2012 | The Plant Journal, Vol. 73, No. 1Rolling circle amplification-RACE: a method for simultaneous isolation of 5′ and 3′ cDNA ends from amplified cDNA templatesAlexios N. Polidoros, Konstantinos Pasentsis & Athanasios S. Tsaftaris21 May 2018 | BioTechniques, Vol. 41, No. 1Simultaneous amplification of 5′ and 3′ cDNA ends based on template-switching effect and inverse PCRJun-Chao Huang & Feng Chen21 May 2018 | BioTechniques, Vol. 40, No. 2Identification of the bull sperm p80 protein as a PH-20 ortholog and its modification during the epididymal transit12 May 2005 | Molecular Reproduction and Development, Vol. 71, No. 4Identification of a novel protein, LYRIC, localized to tight junctions of polarized epithelial cellsExperimental Cell Research, Vol. 300, No. 1Citrus fruit bitter flavors: isolation and functional characterization of the gene Cm1,2RhaT encoding a 1,2 rhamnosyltransferase, a key enzyme in the biosynthesis of the bitter flavonoids of citrus24 August 2004 | The Plant Journal, Vol. 40, No. 1A novel mitogenic protein that is highly expressed in cells of the gastric antrum mucosaAmerican Journal of Physiology-Gastrointestinal and Liver Physiology, Vol. 285, No. 2Type XXIII Collagen, a New Transmembrane Collagen Identified in Metastatic Tumor CellsJournal of Biological Chemistry, Vol. 278, No. 23A Selenoprotein in the Plant KingdomJournal of Biological Chemistry, Vol. 277, No. 29Cloning and characterization of a novel human gene RNF38 encoding a conserved putative protein with a RING finger domainBiochemical and Biophysical Research Communications, Vol. 294, No. 55′-RACEing Across a Bridging OligonucleotideX. Shi, T. Karkut, M. Chahmanhkah, M. Alting-Mees, S.M. Hemmingsen & D. Hegedus17 September 2018 | BioTechniques, Vol. 32, No. 3Evening specific oscillations of scent emission, SAMT enzyme activity, and SAMT mRNA in flowers of Stephanotis floribundaJournal of Plant Physiology, Vol. 159, No. 8Differential expression and subcellular distribution of the mouse metastasis-associated proteins Mta1 and Mta3Gene, Vol. 273, No. 1Molecular cloning of the rat TA1/LAT-1/CD98 light chain gene promoterBiochimica et Biophysica Acta (BBA) - Gene Structure and Expression, Vol. 1518, No. 3Fa1p is a 171 kDa protein essential for axonemal microtubule severing in ChlamydomonasJournal of Cell Science, Vol. 113, No. 11 Vol. 27, No. 4 Follow us on social media for the latest updates Metrics Downloaded 71 times History Published online 22 August 2018 Published in print October 1999 Information© 2018 Author(s)PDF download

β-Glucosidase activity is involved in scent production in Narcissus flowers

Extrinsic environmental cues and intrinsic developmental stages of the flower control the production of scent from flowers. Flowers emit scent only when they are open; yet, the precursors for the aromatic compounds are also present in buds, stored as non-fragrant glycosides in the vacuole. We demonstrate that in Narcissus flowers scent emission is concurrent with an increase in the activity of β-glucosidase. The inhibition in vivo of β-glucosidase activity decreases scent emission from Narcissus flowers. The β-glucosidase activity was partially purified and the K m, V max and inhibition by gluconic acid lactone was determined.

Variation of Floral Scent Emission and Postpollination Changes in Individual Flowers of Ophrys sphegodes Subsp. sphegodes

We investigated the scent composition of individual flowers of Ophrys sphegodes, its alteration following pollination, and of picked flowers by day and at night. Odor samples were collected by headspace sorption and analyzed by gas chromatography and mass spectrometry. To evaluate the function of postpollination odor changes, we carried out behavioral tests on the pollinator Andrena nigroaenea with pollinated and unpollinated flowers. We identified 27 volatiles in the flower scents. Aldehydes and alkanes were most frequently found. Aldehydes were the most abundant class of compounds (40–50%). When flowers were picked, they emitted significantly lower total amounts of volatiles than unpicked flowers, and their odor bouquets were significantly different. Comparison of scents released by day and at night showed no decrease in scent emission during nighttime, but the odor bouquets were significantly different. Pollinated flowers produced significantly different odor bouquets, and the total amount of scent emitted two to four days after pollination was significantly lower compared with unpollinated flowers. In addition, behavioral tests with A. nigroaenea males showed that flowers were significantly less attractive three days after pollination. This reduced attractiveness is hypothesized to guide pollinators to the unpollinated flowers within an inflorescence, and thus increase the reproductive success of the plant.