salicylates and linalool

Adoxophyes honmai, a serious pest of tea plants, prefers to lay eggs on mature tea leaves rather than young leaves. Here, we examined a hypothesis that Ascogaster reticulata, an egg-larval parasitoid of A. honmai, increases the likelihood of encountering host egg masses by searching mature tea leaves when host-derived cues are not available. In a dual-choice bioassay using a four-arm olfactometer, A. reticulata preferred odor from intact, mature leaves versus young leaves. Based on volatile analysis with gas chromatography-mass spectrometry (GC-MS), we identified 5 and 10 compounds from mature and young leaf volatiles, respectively. The 5 components in the extract from intact mature leaves included (Z)-3-hexenyl acetate, (E)-β-ocimene, linalool, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), and methyl salicylate. When each individual compound, or quaternary and quintenary blends of them, ratios of which were adjusted to match those of mature leaf volatiles, were provided, parasitoids preferred the full mixture and the quaternary blend devoid of DMNT to the solvent control. Methyl salicylate, one of the components of preferred blends, was not detected among young leaf volatiles. We concluded that the volatile composition of tea leaves changes, depending on their maturity, and that this composition affects foraging behavior of the parasitoid, which is closely related to the host herbivore's oviposition preference.

Topics: Acetates; Acyclic Monoterpenes; Alkenes; Animals; Camellia sinensis; Ecosystem; Gas Chromatography-Mass Spectrometry; Hymenoptera; Larva; Moths; Odorants; Plant Leaves; Salicylates; Terpenes; Volatile Organic Compounds

Plants have evolved sophisticated defense mechanisms to overcome their sessile nature. However, if and how volatiles from cold-stressed plants can trigger interplant communication is still unknown. Here, we provide the first evidence for interplant communication via inducible volatiles in cold stress. The volatiles, including nerolidol, geraniol, linalool, and methyl salicylate, emitted from cold-stressed tea plants play key role(s) in priming cold tolerance of their neighbors via a C-repeat-binding factors-dependent pathway. The knowledge will help us to understand how plants respond to volatile cues in cold stress and agricultural ecosystems.

Topics: Acyclic Monoterpenes; Camellia sinensis; Cold-Shock Response; Salicylates; Sesquiterpenes

A methodology based on headspace solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) determination was developed for the monitoring and evaluation of the removal efficiency of 16 common fragrance allergens and two polycyclic musks in wastewater treatment plants (WWTPs). An experimental design with a full factorial model was applied to evaluate the effects of the experimental parameters on the extraction (e.g., salt content, time and extraction temperature). After determining the optimum conditions (2.4 g NaCl, 45 min at 90 °C), an external calibration was performed and quality parameters of the proposed method were evaluated. Method detection limits in the range of 0.01-1.7 μg L(-1) were obtained. Satisfactory inter-day precision values between 4% and 23% (n=5) were obtained for most compounds. The method was applied to the monitoring of the target analytes in samples from two WWTPs. Seven target compounds were detected at the primary effluent of both plants at μg L(-1) levels. Limonene, linalool and eugenol were quantitatively eliminated during the secondary treatments of both WWTPs, while lilial, benzyl salicylate, galaxolide, and tonalide were still detected at the effluent waters.

Topics: Acyclic Monoterpenes; Aldehydes; Allergens; Benzopyrans; Cyclohexenes; Eugenol; Fatty Acids, Monounsaturated; Gas Chromatography-Mass Spectrometry; Limonene; Monoterpenes; Odorants; Perfume; Salicylates; Solid Phase Microextraction; Terpenes; Tetrahydronaphthalenes; Wastewater; Water Pollutants, Chemical

In this paper, the volatiles emitted by flowers and various parts of the flower of a rare spontaneous Italian red (peel and flesh) apple named "Pelingo", were analyzed by SPME with the aim of identifying the contribution of each one to the whole aroma profile. Linalool was the most abundant volatile of flowers: from 43.0% in the flower buds, to 17.6% in the stylus and stigma headspace. The second most represented volatile was (E,E)-α-farnesene mainly emitted by the mature flowers (32.2%). Benzenoid compounds also have been identified: benzyl-alcohol is the most representative (1.0-16.5%) in all the samples except flower buds, while benzyl acetate (5.7%) and methyl salicylate (7.7%) are mainly present in the calyx and in the mature flowers respectively but not in the flower buds. Benzenoid compounds are the attractors for pollinator, probably for this reason were not detected in the headspace of flower buds.

Topics: Acyclic Monoterpenes; Benzyl Alcohol; Benzyl Compounds; Fatty Acids, Unsaturated; Flowers; Gas Chromatography-Mass Spectrometry; Italy; Malus; Monoterpenes; Pollination; Salicylates; Volatile Organic Compounds

Deciduous trees remobilize the nitrogen in leaves during the process of autumn coloration, thus providing a high quality food source for aphids preparing to lay over-wintering eggs. It has been suggested that aphids may use volatile organic compounds (VOCs) to: (a) select leaves where nutrient remobilization has started and induced defenses are reduced; and (b) detect the time of leaf abscission. We analyzed VOCs emitted by the foliage of Betula pendula Roth. during autumn coloration and from leaf litter just after leaf fall. We tested the hypothesis that costly, photosynthesis-related terpenes and other herbivore-induced VOCs related to attraction of aphid parasitoids and predators are reduced during the coloration process. We also investigated if the VOC emission profile of abscising leaves is different from that of early stage yellowing leaves. Enemy-luring compounds (E)-β-ocimene, linalool, and (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) were emitted only from the green foliage. Methyl salicylate (MeSa), known to recruit predatory bugs and attract migrant aphids, was emitted until the first stage of color change. Cis-3-hexenol, an indicator of cellular disintegration, became dominant in the emissions from abscising leaves and from fresh leaf litter. We discuss the ecological significance of the observed changes in birch leaf VOC profiles during the process of autumn senescence.

Topics: Acyclic Monoterpenes; Alkenes; Animals; Aphids; Betula; Ecosystem; Monoterpenes; Photosynthesis; Plant Leaves; Salicylates; Seasons; Terpenes; Time Factors; Volatile Organic Compounds

We investigated volatile infochemicals possibly involved in location of the generalist predatory mite Neoseiulus californicus to plants infested with spider mites in a Y-tube olfactometer. The predators significantly preferred volatiles from lima bean leaves infested with Tetranychus urticae to uninfested lima bean leaves. Likewise, they were attracted to volatiles from artificially damaged lima bean leaves and those from T. urticae plus their visible products. Significantly more predators chose infested lima bean leaves from which T. urticae plus their visible products had been removed than artificially damaged leaves, T. urticae, and their visible products. These results suggest that N. californicus is capable of exploiting a variety of volatile infochemicals originating from their prey, from the prey-foodplants themselves, and from the complex of the prey and the host plants (e.g., herbivore-induced volatiles). We also investigated predator response to some of the synthetic samples identified as volatile components emitted from T. urticae-infested lima bean leaves and/or artificially damaged lima bean leaves. The predators were attracted to each of the five synthetic volatile components: linalool, methyl salicylate, (Z)-3-hexen-1-ol, (E)-2-hexenal, and (Z)-3-hexenyl acetate. The role of each volatile compound in prey-searching behavior is discussed.

Topics: Acetates; Acyclic Monoterpenes; Aldehydes; Animals; Chemotactic Factors; Female; Hexanols; Mites; Monoterpenes; Odorants; Phaseolus; Plant Leaves; Predatory Behavior; Salicylates; Smell; Tetranychidae; Volatilization

The Y-olfactometer bioassays showed that the volatiles from tea aphids and tea aphid-damaged tea shoots (PHC) strongly attracted Sphaerophoria menthastri and Chrysopa septempunctata. At the dosage of 10(-4) g x ml(-1), S. menthastri selected geraniol and methyl salicylate from PHC, n-octanol from intact tea shoots (ITS), nerol from tea flowers (P < 0.01), and (E)-2-hexen-1-ol, E-2-hexenal, 1,3,6-octatriene-3,7-dimethyl and linalool from PHC (P < 0.05), while C. septempunctata selected n-octanol and hexanal from ITS (P < 0.05). At the dosage of 10(-2) g x ml(-1), S. menthastri selected hexanal, nerol and benzaldehyde from PHC (P < 0.05), while C. septempunctata selected hexanal, benzaldehyde, geraniol and (E)-2-hexen-1-ol (P < 0.05). The experimental results showed that besides aldehydes and methyl salicylate, geraniol, n-octanol and (E)-2-hexen-1-ol were significantly attractive to the natural enemies. The selective responses of natural enemies were restricted by thresholds. Both dosages of hexanal significantly attracted C. septempunctata. Nerol might be an infochemicals seducing S. menthastri to orient to tea flowers.

Topics: 1-Octanol; Acyclic Monoterpenes; Animals; Behavior, Animal; Chemotactic Factors; Chemotaxis; Diptera; Dose-Response Relationship, Drug; Flowers; Insecta; Monoterpenes; Odorants; Plant Extracts; Plant Shoots; Salicylates; Tea; Terpenes; Volatilization

There is increasing evidence that volatiles emitted by herbivore-damaged plants can cause responses in downwind undamaged neighboring plants, such as the attraction of carnivorous enemies of herbivores. One of the open questions is whether this involves an active (production of volatiles) or passive (adsorption of volatiles) response of the uninfested downwind plant. This issue is addressed in the present study. Uninfested lima bean leaves that were exposed to volatiles from conspecific leaves infested with the spider mite Tetranychus urticae, emitted very similar blends of volatiles to those emitted from infested leaves themselves. Treating leaves with a protein-synthesis inhibitor prior to infesting them with spider mites completely suppressed the production of herbivore-induced volatiles in the infested leaves. Conversely, inhibitor treatment to uninfested leaves prior to exposure to volatiles from infested leaves did not affect the emission of volatiles from the exposed, uninfested leaves. This evidence supports the hypothesis that response of the exposed downwind plant is passive. T. urticae-infested leaves that had been previously exposed to volatiles from infested leaves emitted more herbivore-induced volatiles than T. urticae-infested leaves previously exposed to volatiles from uninfested leaves. The former leaves were also more attractive to the predatory mite, Phytoseiulus persimilis, than the latter. This shows that previous exposure of plants to volatiles from herbivore-infested neighbors results in a stronger response of plants in terms of predator attraction when herbivores damage the plant. This supports the hypothesis that the downwind uninfested plant is actively involved. Both adsorption and production of volatiles can mediate the attraction of carnivorous mites to plants that have been exposed to volatiles from infested neighbors.

Topics: Acyclic Monoterpenes; Adaptation, Physiological; Adsorption; Alkenes; Animals; Chemotactic Factors; Mites; Monoterpenes; Phaseolus; Pheromones; Plant Leaves; Protein Synthesis Inhibitors; Salicylates; Terpenes; Tetranychidae; Time Factors; Volatilization