Volatile emissions of eastern hemlock,Tsuga canadensis,and the influence of hemlock woolly adelgid

The volatile emissions of eastern hemlock, Tsuga canadensis Carriere, were identified and quantified using standard and chiral gas chromatography and mass spectrometry. All of the identified compounds were monoterpenes, and included alpha-pinene, myrcene, tricyclene, camphene, alpha-phellandrene, beta-pinene, limonene, beta-phellandrene, terpinolene, and bornyl acetate. alpha-Pinene, myrcene, and camphene comprised greater than 75% by mass of the total release. Infestation by the exotic insect, hemlock woolly adelgid (HWA, Adelges tsugae Annand), resulted in an increased release rate of monoterpenes from branch tips. Release rate was negatively correlated to the amount of the branch tip sample that was new growth, suggesting that release rate is greater from previous-year foliage. Additionally the percent composition of the volatile profile is slightly altered by infestation, with alpha-pinene comprising 57% of volatiles from infested foliage and 66% from uninfested foliage.     

Foliar and cortex oleoresin variability of silver fir (Abies alba Mill.) in Albania

Terpene composition of needle and cortical oleoresin from lateral shoots were analyzed by GC/MS for four Silver fir (Abies alba Mill.) populations scattered in natural species range in Albania. More than sixty compounds were detected in the needle oleoresin, which was characterized by a high content of alpha-pinene, camphene, beta-pinene, limonene and bornyl acetate. Three monoterpenes, alpha-pinene, beta-pinene and limonene, and two sesquiterpenes, beta-caryophyllene and germacrene D, comprised the majority of cortical oleoresin. The terpene composition differences among the populations that led to the recognition of two chemotypes. The needle oleoresin from the provinces of Puka, Bulqiza and Llogara were characterised by high amounts of beta-pinene, camphene and alpha-pinene and low amounts of limonene, while that from Drenova had high amounts of beta-pinene and limonene. A similar pattern was found in the cortical oleoresin with the exception of camphene that was a minor contributor. Geographical and seasonal variation between the populations was, also, investigated. Multivariate analysis of both needle and cortical oleoresin separated Drenova (southeastern population) from the other sites. When both major monoterpenes and sesquiterpenes were considered four chemical profiles could be attributed. Based on their chemical profiles, the populations can be divided into two groups: Populations with high content of beta-pinene and alpha-pinene but a low content of limonene (Puka, Bulqiza and Llogara), typical of most of A. alba populations in all its distribution range. Population with a high content of limonene and a moderate content of beta-pinene and alpha-pinene (Drenova).     

Between plant and diurnal variation in quantities and ratios of volatile compounds emitted by Vicia faba plants

Ratios of volatile phytochemicals potentially offer a means for insects to recognise their host-plant species. However, for this to occur ratios of volatiles would need to be sufficiently consistent between plants and over time to constitute a host-characteristic cue. In this context we collected headspace samples from Vicia faba plants to determine how consistent ratios of key volatile phytochemicals used in host location by one of its insect pests, the black bean aphid, Aphis fabae, were. These were (E)-2-hexenal, (Z)-3-hexen-1-ol, 1-hexanol, benzaldehyde, 6-methyl-5-hepten-2-one, octanal, (Z)-3-hexen-1-yl acetate, (R)-linalool, methyl salicylate, decanal, undecanal, (E)-caryophyllene, (E)-β-farnesene, (S)-germacrene D, and (E, E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene, which had previously been found to be electrophysiologically and behaviourally active to A. fabae. Although the quantities of volatiles produced by V. faba showed large between plant and diurnal variation, correlations between quantities of compounds indicated that the ratios of certain pairs of volatiles were very consistent. This suggests that there is a host-characteristic cue available to A. fabae in the form of ratios of volatiles.     

三种绿叶挥发性物质对云南切梢小蠹寄主定位行为的干扰作用

为了研究环境中非寄主阔叶植物释放出的绿叶挥发性物质（GLVs）对针叶树蛀干害虫云南切梢小蠹Tomicus yunnanesis的影响, 选取了(E)-2-己烯醛、 (E)-2-己烯醇和(Z)-3-己烯醇3种释放量较大的绿叶挥发性物质, 通过室内松梢取食试验测试了单组分及两两混合后对云南切梢小蠹寄主定位行为的干扰作用。结果表明： 源于阔叶植物的3种绿叶挥发性物质及其混合物能够不同程度干扰云南切梢小蠹的寄主定位行为。当虫放入广口瓶12 h后, 3个单组分绿叶挥发性物质处理组［A： (E)-2-己烯醛, P＜0.01; B： (E)-2-己烯醇, P＜0.01; C： (Z)-3-己烯醇, P＜0.01］及2个混合组分［D： (E)-2-己烯醛+(E)-2-己烯醇, P＜0.01）; E： (E)-2-己烯醛+(Z)-3-己烯醇, P＜0.01］中滞留在松梢外部的虫数与对照组相比都有显著性差异, 绿叶挥发性物质的存在显著降低了云南切梢小蠹侵害云南松松梢的概率。但是, 24 h后只有D组（P＜0.01）和E组（P＜0.01）滞留在松梢外部的虫数与对照组相比具有显著性差异, 在48 h后只有D组（P＜0.01）与对照相比仍具有显著性差异。本研究为利用非寄主植物的次生代谢产物防治云南切梢小蠹进行了有益的探索。     

Volatiles induced by the larvae of the Asian corn borer (Ostrinia furnacalis) in maize plants affect behavior of conspecific larvae and female adults

Abstract  Effects of maize ( Zea mays L.) volatiles induced by larvae of the Asian corn borer, Ostrinia furnacalis (Guenée), on the orientation behaviors of Asian corn borer larvae and oviposition of the females were investigated. Nineteen volatile chemicals, with terpenes being the major components, were identified from maize plants attacked by third instar Asian corn borer larvae. Coupled gas chromatographic-electroantennographic detection (GC-EAD) analyses revealed some electroantennographic differences between female and male Asian corn borer antennae in response to larvae-induced maize volatiles; female responded to ( E )-2-hexenal, nonanal, ( Z )-3-hexen-1-ol and three unknown compounds while the male only responded to ( E )-2-hexenal, nonanal and one unknown compound. In laboratory orientation bioassays, Asian corn borer neonate larvae were attracted to extracts collected from Asian corn borer-damaged plants as well as to synthetic farnesene, but were repelled by ( Z )-3-hexen-1-ol. In laboratory oviposition bioassays, gravid females laid fewer eggs on plants damaged by larvae than on mechanically damaged plants or undamaged plants. Adult Asian corn borer females deposited fewer eggs on wax paper treated with ( E )-2-hexenal or ( Z )-3-hexen-1-ol than on wax paper treated with hexane (control). The results suggest that Asian corn borer can affect the behaviors of conspecific larvae and adults by changing host plant volatiles.     

Application of multidimensional gas chromatography to the enantioselective characterisation of the essential oil of Eupatorium buniifolium Hooker et Arnott

The qualitative and quantitative composition of the essential oil from aerial parts of Eupatorium buniifolium Hooker et Arnott (Asteraceae) has been investigated for the first time. The essential oils were obtained by steam distillation of leaves and analysed by GC-MS; 44 components were identified. Monoterpene and sesquiterpene hydrocarbons, especially alpha-pinene (14.7%), beta-elemene (12.2%), germacrene D (11.5%), trans-beta-guaiene (6.5%) and (E)-caryophyllene (4.3%), were the major constituents found in the oils. The characterisation of E. buniifolium by enantioselective GC was performed by evaluation of the enantiomeric ratios of alpha-pinene, sabinene, beta-pinene, limonene, terpinen-4-ol and germacrene D.     

Volatile oil comparison of cotyledon leaves of chemotypes of Melaleuca alternifolia

Oil quantity and quality were measured for the cotyledon leaves of the commercial terpinen-4-ol chemical variety of Melaleuca alternifolia. Oil yield obtained by ethanolic extraction was 3.8 micrograms per leaf or 2.6% (dry weight basis). The major components of the oil were alpha-pinene (7.4%), beta-pinene (12.0%) and terpinolene (27.3%). The non-commercial terpinolene chemical variety was found to be rich in 1,8-cineole (12.5%) and terpinolene (25.4%). The non-commercial 1,8-cineole chemical variety was rich in 1,8-cineole (37%) with significant quantities of alpha-pinene (15.5%), beta-pinene (23.3%) and terpinolene (10.9%). The cotyledon leaf composition, when compared with that of mature leaf from the same chemical variety, was found to be biased toward pinene and terpinolene biogenetic pathway constituents and hence not a good indicator of mature tree quality especially for the commercial terpinen-4-ol chemical variety. The implications of these analyses for the determination of M. alternifolia plantation quality and the understanding of oil formation, are discussed.     

Seasonal variation of monoterpene emission from Malus domestica and Prunus avium

Emission rates of monoterpenes released by apple (Malus domestica Borkh) and cherry (Prunus avium L.) were estimated at different phenological stages. These measurements employed a dynamic flow-through Teflon chamber, sample collection onto cartridges filled with graphitized carbon and thermal desorption gas chromatography-mass spectrometry (GC-MS) for identification and quantification of the emitted volatiles. At full bloom the release of monoterpene hydrocarbons from cherry flowers was 1213 ng g(-1) dry weight (DW) h(-1), exceeding by approximately three-fold the emission rate of apple flowers (366 ng g(-1) DW h(-1)). Observed seasonal variations in biogenic volatile organic compound (VOC) emissions ranged over several order of magnitudes. At fruit-set and ripening stages, in fact, the hydrocarbon emission dramatically decreased reaching the lowest values at harvest time when leaves were fully mature (3-9 ng g(-1) DW h(-1)). Wide diversity in the composition of compounds from the species studied was also recorded. At blooming, linalool contributed significantly to the monoterpene emission from apple (94% of the emitted carbon) while alpha-pinene and camphene represented on average more than 60% of the total emitted volatiles from cherry flowers. Among the monoterpenes identified in flowers, alpha-pinene, camphene and limonene were also found in the foliage emission of both species. Fruit trees are relevant monoterpene emitters only at blooming and thus for a short period of the vegetative cycle. When leaves are fully developed, the carbon loss due to monoterpene emissions related to the photosynthetically carbon gain is negligible.     

Increased EAG responses of tortricid moths after prolonged exposure to plant volatiles: evidence for octopamine-mediated sensitization

As measured by electroantennograms (EAG), both male and female obliquebanded leafrollers, Choristoneura rosaceana (Harris), and redbanded leafrollers, Argyrotaeniavelutinana (Walker), were similarly sensitive to host-related plant volatiles: trans-2-hexenal, benzaldehyde, 1-hexenol, cis-3-hexen-1-ol, geraniol, linalool, (+)-limonene, hexenal and trans-2-hexenol. Females of both species were similarly sensitive to the shared major component of their sex-attractant pheromone ((Z)11-14:Ac). Continuous 60 min pre-exposure of male and female C. rosaceana and A. velutinana to successively higher concentrations of a mixture of the nine plant volatiles in Teflon chambers with continuous air exchange caused a dosage-dependent increase in subsequent responsiveness (sensitization) to green leaf volatiles, as measured by EAGs. In addition, 60 min of pre-exposure of male C. rosaceana to certain individual volatiles ((+)-limonene, geraniol, benzaldehyde) increased EAGs nearly as much as did the mixture of nine volatiles. Pre-exposures to the nine plant-volatile mixture at concentrations achieved by 100 microg and 1 mg loading dosages in 100 microl of mineral oil significantly increased EAG depolarization to pheromone (cross-sensitization) in males but not females of both moth species. Antennae of male C. rosaceana pre-injected with 100 microg of octopamine (OA) without volatile pre-exposure exhibited sensitization nearly identical to that induced by pre-exposing moths to sensitizing concentrations of the plant-volatile mixture. Moreover, injection of the OA antagonist chlorpromazine (CP) blocked sensitization by the plant-volatile pre-exposure. Collectively, these findings suggest that exposures of tortricid moths to certain host-plant related volatiles may modulate subsequent olfactory sensitivity to behaviorally relevant chemical cues and that plant-volatile induced sensitization may be octopamine mediated.     

Nonhost angiosperm volatiles and verbenone disrupt response of western pine beetle, Dendroctonus brevicomis (Coleoptera: Scolytidae), to attractant-baited traps

Nonhost angiosperm volatiles and verbenone were tested for their ability to disrupt the response of western pine beetle, Dendroctonus brevicomis LeConte (Coleoptera: Scolytidae), to attractant-baited multiple funnel traps. Verbenone significantly reduced attraction; however, no difference was observed between 4 and 50 mg/24-h release rates. Combinations of six bark volatiles (benzyl alcohol, benzaldehyde, trans-conophthorin, guaiacol, nonanal, and salicylaldehyde), three green leaf volatiles [(E)-2-hexenal, (E)-2-hexen-1-ol, and (Z)-2-hexen-1-ol], and the nine compounds combined did not significantly reduce D. brevicomis response to attractant-baited traps. However, a significant effect was observed when the bark and green leaf volatiles were combined with verbenone. The nine nonhost angiosperm volatiles (NAVs) significantly augmented the effect of both release rates of verbenone, reducing trap catches to levels significantly below that of either release rate of verbenone alone. trans-Conophthorin, a compound reported to have behavioral activity in a number of other scolytids, was not critical to the efficacy of our NAV blend. Our results suggest that the addition of nonhost angiosperm volatiles to verbenone could be important for developing successful semiochemical-based management techniques for D. brevicomis.     

Pine shoot beetle, Tomicus piniperda (Col., Scolytidae), responses to common green leaf volatiles

We tested the hypothesis that green leaf volatiles (GLVs) disrupt the response of overwintered pine shoot beetles, Tomicus piniperda (L.) to multiple-funnel traps baited with the attractive host volatile α-pinene. A combination of four GLV alcohols, 1-hexanol ( E )-2-hexen-1-ol ( Z )-2-hexen-1-ol, and ( Z )-3-hexen-1-ol, caused 54 and 36% reduction in the number of pine shoot beetles captured in two separate trapping experiments. Similarly, a combination of the four alcohols plus two GLV aldehydes, hexanal and ( E )-2-hexenal, caused 38% reduction in the number of pine shoot beetles captured compared with α-pinene alone. A blend of the two GLV aldehydes was not disruptive. None of the four GLV alcohols nor the two GLV aldehydes were disruptive when tested individually. The finding that the blend of four GLV alcohols reduced attraction of T. piniperda supports the general hypothesis that GLVs common to nonhost angiosperms are disruptive to conifer-attacking bark beetles (Scolytidae).     

Electroantennogram responses of the carrot fly, Psila rosae, to volatile plant components

ABSTRACT. Electroantennogram (EAG) responses of male and female carrot flies, Psila rosae F. (Diptera: Psilidae), were recorded to thirty-six volatile plant constituents. The most distinct EAG responses were obtained to: (1) the general green leaf volatiles 1-hexanol, trans-2-hexen-1-ol and cis-3-hexen-1-ol, their isomers cis-2-hexen-1-ol and trans-3-hexen-1-ol, the alcohol 1-heptanol, the ester cis-3-hexenyl acetate and the leaf aldehydes hexanal and trans-2-hexenal, and (2) from four compounds associated with the umbelliferous host plants of this insect, namely trans-methyl-iso-eugenol, β-caryophyllene, linalool and trans-2-nonenal. Higher responses were elicited by the leaf aldehydes than by the corresponding alcohols. Although the absolute amplitude of the female response was over twice that of the male, there were no differences between the relative responses to the compounds tested in both sexes, with the exception of a much higher response to the leaf aldehydes in the male. The shape of the EAG evoked by the various compounds was consistently different, with the slowest recovery being recorded for trans-methyl-iso-eugenol. While the antennal olfactory receptors of the carrot fly are sensitive to the closely related general green leaf volatiles, they are most specifically tuned to the aldehyde component of this green odour complex. In addition, the ability of this insect to discriminate between different plants may be augmented by the perception of a group of more host specific volatiles. The conformity of the responses of males and females to the compounds tested may indicate that host plant volatiles plays an additional role as an aggregation cue for both sexes.     

Responses of Dendroctonus brevicomis (Coleoptera: Curculionidae) in behavioral assays: implications to development of a semiochemical-based tool for tree protection

Currently, techniques for managing western pine beetle, Dendroctonus brevicomis LeConte (Coleoptera: Curculionidae, Scolytinae), infestations are limited to tree removals (thinning) that reduce stand density and presumably host susceptibility, and/or the use of insecticides to protect individual trees. There continues to be significant interest in developing an effective semiochemical-based tool for protecting trees from D. brevicomis attack, largely as an alternative to conventional insecticides. The responses of D. brevicomis to tree volatiles and verbenone were documented in eight experiments (trapping assays) conducted over a 4-yr period in which 88,942 individuals were collected. Geraniol, a tree volatile unique to Pinus ponderosa that elicits female-specific antennal responses in D. brevicomis, did not affect D. brevicomis behavior. Blends of two green leaf alcohols [hexanol + (Z)-3-hexen-1-ol] tested at two release rates (5.0 and 100.0 mg/d) had no effect on the response of D. brevicomis to attractant-baited traps. A nine-component blend [benzaldehyde, benzyl alcohol, guaiacol, nonanal, salicylaldehyde, (E)-2-hexenal, (E)-2-hexen-1-ol, (Z)-2-hexen-1-ol, and (-) -verbenone; NAVV] and subsequent revisions of this blend disrupted the response of D. brevicomis to attractant-baited traps in all experiments. The inhibitory effect of a revised five-component blend [nonanal, (E)-2-hexenal, (E)-2-hexen-1-ol, (Z)-2-hexen-1-ol, and (-)-verbenone; NAVV5] on the response of mountain pine beetle, D. ponderosae Hopkins, to attractant-baited traps was also documented. Acetophenone significantly reduced D. brevicomis attraction, but was not as effective as verbenone alone. Acetophenone increased the effectiveness of NAVV5 in one of two experiments. Furthermore, by adding acetophenone to NAVV5 we were able to remove the aldehydes from NAVV5 without compromising effectiveness, resulting in a novel four-component blend [acetophenone, (E)-2-hexen-1-ol + (Z)-2-hexen-1-ol, and (-)-verbenone; Verbenone Plus]. We discuss the implications of these and other results to development of Verbenone Plus as a semiochemical-based tool for management of D. brevicomis and D. ponderosae infestations.     

Role of plant volatiles in host plant location of the leafminer, Liriomyza sativae (Diptera: Agromyzidae)

Abstract The role of plant volatiles in host plant location of the leafminer Liriomyza sativae Blanchard was studied. Four types of antennal sensilla were identified on the funiculus by scanning electron microscopy: trichoid, basiconic, clavate and grooved sensilla. An olfactory pit, containing groups of sensilla, was present on the ventral side of the funiculus. No sexual difference was detected in sensilla diversity and distribution. In behavioural assays, both males and females were attracted by the odour of the bean Phaseolus vulgaris L. They had distinct EAG responses to the bean odour. No significant sexual difference was found in behaviour or EAG responses.
Electroantennograms were recorded from female L. sativae to 14 plant volatile compounds. The most distinct EAG responses were obtained for: (1) the general green leaf volatiles 1-hexanol (E)-2-hexen-1-ol, (E)-3-hexen-1-ol and its isomers, (Z)-3-hexen-1-ol, the acetate (E)-3-hexenylacetate and the aldehyde hexanal; and (2) limonene, a compound associated with tomato, which is a key host plant of this insect. Other volatile compounds associated with host plants, such as α-pinene, myrcene, β-caryophyllene, and eugenol did not elicit responses. The ability of this insect to locate a host plant appears to be augmented by the perception of a combination of host-specific and general green leaf volatiles. A modification of the EAG recording method of Dipteran species was provided.     

Composition of the volatiles from intact and tea aphid-damaged tea shoots and their allurement to several natural enemies of the tea aphid

Abstract: The comparison between the composition of the volatiles from intact tea shoots (ITS) and that from tea aphid-damaged tea shoots (TADTS) was accomplished, and the difference of both volatiles in attraction to natural enemies of the tea aphid, Toxoptera aurantii , i.e the ladybug, Leis axyridis (Pallas), the aphid parasite, Aphidius sp., and the lacewing, Chrysopa septempunctata Wesmeal, was investigated in the current paper. Volatile components from ITS, obtained by air entrainment, were identified by their mass spectra and retention times and comfirmed by comparison with authentic samples. They are E-2-hexenal, ocimene, Z-3-hexenyl acetate, Z-3-hexen-1-ol, butanoic acid-3-hexenyl ester, linalool, 1-octanol, geraniol and indole. Volatiles from TADTS have been identified as E-2-hexenal, ocimene, Z-3-hexenyl acetate, Z-3-hexen-1-ol, linalool, geraniol, indole, benzaldehyde and E-2-hexenoic acid. Z-3-hexen-1-ol is the main component in the two kinds of volatiles, whilst benzaldehyde is the another main component in TADTS volatiles. The air entrainment extracts of TADTS and benzaldehyde elicit the stronger electroantennogram (EAG) responses, and the stronger upwind flight and arresting behaviour from each natural enemy in wind tunnel. EAG responses from Leis axyridis and Chrysopa septempunctata were bigger than those from Aphidius sp., whereas Leis axyridis responds to these odours slightly less than Aphidius sp. and Chrysopa septempunctata in wind tunnel bioassay. So TADTS emits volatile synomones, in which the amount of benzaldehyde is ample and its allurement is the strongest.     

Drought stress of apple trees alters leaf emissions of volatile compounds

Actively growing potted apple trees ( Malus domestica [L.] Borkh. ev. Delicious) unacclimated to drought stress were subjected to drought to determine changes in emissions of leaf volatile compounds. Drought stress was imposed over a 2-week period by weighing pots every 2 or 3 days and adding water hack to an arbitrary and decreasing traction of the original pot weight. Stem water potential was -2.7. -2.0 and -0.8 MPa for the severely stressed, moderately stressed and control trees, respectively. 13 days alter watering treatments were begun. Water use the last 4 days of the experiment was about one-half for the moderately and severely stressed trees compared to that of the controls Twenty-nine volatile compounds were identified by using gas chromatography and mass spectroscopy. Emission rates of hexanal, (E)-2-hexenal, (E)-2-hexen-1-ol, 1-hexenol, hexyl acetate and (E)-2-hexenyl acetate were 5 to 310 times higher for severely stressed trees compared to those of the controls with the moderately stressed trees intermediate. The large increases in hexanal. (E)-2-hexenal and l-hexanol may be related. In enhanced lipoxygenase activity. Volatile compounds are products of metabolism and measurement of their changes after biotic or abiotic stresses will increase understanding of the relationship of changes in plant metabolism by those stresses.     

Intermittent exposure to traces of green leaf volatiles triggers the production of (Z)-3-hexen-1-yl acetate and (Z)-3-hexen-1-ol in exposed plants

Intermittent exposure during a period of 3 weeks of undamaged Arabidopsis plants to trace amounts of volatiles emitted by freshly damaged Arabidopsis plants resulted in an increase of subsequent artificial-damage-induced production of (Z)-3-hexen-1-yl acetate and (Z)-3-hexen-1-ol in the exposed Arabidopsis plants when compared with Arabidopsis plants exposed to undamaged Arabidopsis plant volatiles (control plants). We previously showed that (Z)-3-hexen-1-yl acetate attracts a parasitic wasp, Cotesia glomerata. Thus, the induced production of this volatile explained our previously reported finding that, when artificially damaged, the exposed plants were more attractive to C. glomerata than control plants.     

Monoterpene synthase activities in leaves of Picea abies (L.) Karst. and Quercus ilex L

In addition to direct ecological functions in the interaction of plants with the environment, the emission of monoterpenes, especially from the foliage of evergreen trees, is of great importance for the production of ozone and photochemical oxidants in the troposphere. In the present work, we established a reproducible non-radioactive standard enzyme assay and characterized monoterpene synthase activities in needles of Norway spruce (Picea abies (L.) Karst.) and in leaves of holm oak (Quercus ilex L.). In Norway spruce, the dominant monoterpenes formed were alpha-pinene, camphene, and to a lesser extent beta-pinene and limonene. In holm oak, alpha-pinene, sabinene, and beta-pinene were the main products, while limonene was a minor component. Under optimum conditions, in both Norway spruce and holm oak, monoterpene formation remained constant up to 180 min and 90 min, respectively, and varied with the buffer and Mg2+ and Mn2+ concentrations used. Optimum temperature for monoterpene synthase activity was 40 degrees C in both species; optimal pH ranged between 6.5 and 7.5 in both species. Apparent Michaelis-constants for the substrate GDP were ca. 17.9 +/- 5.1 microM for Norway spruce and ca. 69.4 +/- 22.1 microM for holm oak. Molecular weight determination by FPLC indicated that the monoterpene synthases in Norway spruce and holm oak have native molecular weights of ca. 59 and 50 kDa, respectively.     

Gas chromatography-mass spectrometry study of the essential oils of Schinus longifolia (Lindl.) speg., Schinus fasciculata (Griseb.) I. M. Johnst., and Schinus areira L

The essential oil composition from the aerial parts of three Anacardiaceae growing in Bahía Blanca, Argentina was studied by gas chromatography and gas chromatography-mass spectrometry. The essential oils of S. longifolia and S. fasciculata have been studied for the first time. The major constituents were alpha-pinene (46.5%), beta-pinene (15.1%) and alpha-phellandrene (10.1%) for S. longifolia and limonene (10.9%), beta-phellandrene (6.16%) and alpha-phellandrene (5.6%) for S. fasciculata. The major components of the essential oil of S. areira were limonene (28.6%), alpha-phellandrene (10.1%), sabinene (9.2%) and camphene (9.2%) differing from the literature data. The essential oils from S. areira and S. longifolia exhibited a high biotoxicity in a brine shrimp assay with Artemia persimilis.     

茶梢和茶花主要挥发物对门氏食蚜蝇和大草蛉引诱效应

用Y形嗅觉仪进行的生测表明茶二叉蚜和蚜害茶梢复合体挥发物显著引诱门氏食蚜蝇和大草蛉．剂量为10^-4g·ml^-1时,在味源和空气对照之间,食蚜蝇对源于复合体的香叶醇和水杨酸甲酯、源于完整茶梢的正辛醇、源于茶花的橙花醇有极显著趋性(P<0．01),对源于复合体的反-2-己烯-1-醇、反-2-己烯醛、罗勒烯和芳樟醇有显著趋性(P<0．05);大草蛉则显著趋向源于完整茶梢的正辛醇和己醛(P<0．05)．剂量为10^-2g·ml^-1时,食蚜蝇对己醛、橙花醇及源于复合体的苯甲醛有显著趋性,大草蛉显著趋向于苯甲醛、己醛、香叶醇和反-2-己烯-1-醇．结果表明,除了醛类和水杨酸甲酯外,香叶醇、正辛醇和反-2-己烯-1-醇等也有显著引诱效应。2种天敌对信息物的反应是有阈值的,两种剂量的己醛均显著引诱大草蛉,橙花醇是引导食蚜蝇朝茶花定向的信息物。