02602nas a2200253   4500008004100000245013900041210006900180260027100249300001400520490000700534520150200541653001502043653003002058653001402088653001802102653002702120653001702147100001902164700002202183700001402205700001802219700001402237856009702251       2003                        eng d00aQualitative and quantitative variation in monoterpene co-occurrence and composition in the essential oil of Thymus vulgaris chemotypes0 aQualitative and quantitative variation in monoterpene cooccurren  aAffiliation: Ctr. d'Ecologie Fonct. et Evolutive, CNRS, 1919 Route de Mende, 34293 Montpellier Cedex 5, France; Affiliation: Lab. Chim. des Huiles Essentielles, Universite Blaise Pascal de Clermont, Campus des Cézeaux, 24 Avenue des Landais, 63177 Aubiec2003/04//  a859 - 8800 v293 aThymus vulgaris has a chemical polymorphism with six different chemotypes that show marked spatial segregation in nature. Although some populations have a single chemotype in majority, many have two or three chemotypes. In this study we analyze the quantitative variation among T. vulgaris populations in the percentage of oil composed of the dominant monoterpene(s) for each chemotype. In general, phenolic chemotypes (thymol and carvacrol), which occur at the end of the biosynthetic chain, have a significantly lower proportion of their oil composed of their dominant monoterpene than nonphenolic chemotypes (geraniol, α-terpineol, and linalool). This is due to the presence of high amounts of precursors (γ-terpinene and paracymene) in the oil of phenolic chemotypes. The essential oil of the nonphenolic thuyanol chemotype has four characteristic monoterpenes that together make up a lower proportion of the oil than the single dominant monoterpene of the other nonphenolic chemotypes. For all chemotypes, the percentage composition of the dominant monoterpene decreased significantly at sites where the chemotype is not the majority type. This decrease is correlated with a significant increase in either the proportion of the two precursors for the thymol chemotype or the monoterpenes characteristic of the other chemotypes at the site. The latter result suggests that a plant with dominant genes is responsible for the production of different monoterpenes can produce several molecules.10aAdaptation10aEssential oil composition10aLamiaceae10aMediterranean10aMonoterpene production10aPolymorphism1 aThompson, J, D1 aChalchat, J, C -C1 aMichet, A1 aLinhart, Y, B1 aEhlers, B  uhttp://www.scopus.com/scopus/inward/record.url?eid=2-s2.0-0242499958&partnerID=40&rel=R6.5.002436nas a2200241   4500008004100000245009100041210006900132260001400201300001400215490000700229520167100236100001901907700001601926700001301942700001701955700001401972700001401986700001502000700002302015700002102038700001802059856011702077       2007                        eng d00aOngoing adaptation to mediterranean climate extremes in a chemically polymorphic plant0 aOngoing adaptation to mediterranean climate extremes in a chemic  c2007/08//  a421 - 4390 v773 aAlthough extreme climatic events may have profound effects on ecological systems. there is a marked lack of information on adaptation to such events. In this study, we employed reciprocal transplantation on both a geographic scale (experimental sites 200 kin apart in different parts of the range of the study species) and a local landscape scale (reciprocal Populations separated by 2-8 km) to study the performance of different chemical forms of Thymus vulgaris which naturally occur in different climatic environments. Survival and growth were analyzed in relation to long-term and contemporary climate data in natural Populations and our experimental sites. The reciprocal transplants involved a period of six years for clones transplanted in experimental field sites on a geographic scale and three years for seedlings transplanted among natural populations at the local landscape level. Cloned transplants on a geographic scale produced evidence for local adaptation to either summer drought, primarily following the extreme summer drought of 2003, or severe early-winter freezing. Chemotypes that show high survival after intense summer drought showed poor survival after intense early-winter freezing and vice versa, results which directly accord with climate data for their original sites. On the local landscape scale, we found further evidence for local adaptation to summer drought but not to winter freezing (probably due to the absence of extreme freezing during the three years of this study). Future modifications to the occurrence and frequency of extreme climate events may have a profound influence on the spatial distribution of thyme chemotypes.1 aThompson, J, D1 aGauthier, P1 aAmiot, J1 aEhlers, B, K1 aCollin, C1 aFossat, J1 aBarrios, V1 aArnaud-Miramont, F1 aKeefover-Ring, K1 aLinhart, Y, B  uhttps://thymus.myspecies.info/ref/ongoing-adaptation-mediterranean-climate-extremes-chemically-polymorphic-plant01868nas a2200181   4500008004100000245010800041210006900149260001400218300001400232490000800246520120800254100001801462700002101480700001701501700001501518700001901533856013401552       2005                        eng d00aA chemical polymorphism in a multitrophic setting: Thyme monoterpene composition and food web structure0 achemical polymorphism in a multitrophic setting Thyme monoterpen  c2005/10//  a517 - 5290 v1663 aWe investigated the effects of chemical variation in thyme ( Thymus vulgaris L.) on its interactions with competitors, herbivores, and herbivore predators. Four different thyme monoterpene phenotypes ( chemotypes) were grown in a factorial of chemo- 4 x 2 x 2 type, caging ( sham half-cages vs. full cages), and competition ( control vs. the grass Bromus madritensis L.). Cages reduced numbers of arthropod predators. Thyme-feeding aphids Aphis serpylli Koch passed through full cage walls to increase more than fourfold. As a result, freed from their predators, aphids had a large negative effect on thyme size and flowering. Similarly, competition from Bromus had a negative effect on thyme size and flowering. Individual effects of aphids and competition were nonadditive, however, and their combined effect was significantly less than that predicted by a multiplicative null model. Differential thyme sizes among chemotypes were not mediated by herbivores or competitors, but differential flowering was due to the effects of chemotype on aphids. We thus document differential selection by aphids among thyme chemotypes and the influence of Bromus on the strength of these negative effects of aphids.1 aLinhart, Y, B1 aKeefover-Ring, K1 aMooney, K, A1 aBreland, B1 aThompson, J, D  uhttps://thymus.myspecies.info/ref/chemical-polymorphism-multitrophic-setting-thyme-monoterpene-composition-and-food-web-structure01666nas a2200145   4500008004100000245008300041210006900124260001400193300001400207490000600221520115000227100001801377700001901395856010601414       1999                        eng d00aThyme is of the essence: Biochemical polymorphism and multi-species deterrence0 aThyme is of the essence Biochemical polymorphism and multispecie  c1999/02//  a151 - 1710 v13 aPopulations of the common thyme (Thymus vulgaris, Labiatae) are characterized by a complex genetic and biochemical polymorphism. Individual plants manufacture a single dominant monoterpene which gives them a characteristic smell and taste, and the genetic determination of these chemotypes involves a series of five loci interacting with each other in epistatic fashion. We tested the hypothesis that multi-species herbivory and allelopathy are associated with this monoterpene polymorphism. We compared the relative attractiveness and deterrence of various chemotypes by offering either thyme plants or artificial diets laced with monoterpenes to six herbivores: two molluscs, two insects and two mammals. In addition, we summarize experiments by us and others in which bacteria, fungi and seeds of the grass Brachypodium phoenicoides, a common competitor of T. vulgaris, were exposed to the individual monoterpenes. The results show that the monoterpenes have differential deterrence value against these various species. We conclude that a combination of selective herbivory and allelopathy contributes to the maintenance of this polymorphism.1 aLinhart, Y, B1 aThompson, J, D  uhttps://thymus.myspecies.info/ref/thyme-essence-biochemical-polymorphism-and-multi-species-deterrence02369nas a2200145   4500008004100000245009600041210006900137260010400206300001400310490000800324520175700332100001802089700001902107856009702126       1995                        eng d00aTerpene-based selective herbivory by Helix aspersa (Mollusca) on Thymus vulgaris (Labiatae)0 aTerpenebased selective herbivory by Helix aspersa Mollusca on Th  aAffiliation: Univ.CO,Dept Environ.Popul.& Orgmic Biol., Boulder, CO 80309, United Statesc1995/04//  a126 - 1320 v1023 aIn natural populations of Thymus vulgaris in the south of France, six genetically different chemical ''chemotypes'' occur, each differentiated by a single dominant monoterpene that gives individual plants a characteristic smell and taste. Individual populations may contain all six chemotypes, but are often dominated by one to three chemotypes. We tested the hypothesis that this chemical polymorphism was associated with selective herbivory by the snail Helix aspersa, which feeds upon T. vulgaris in nature. The relative preference of juvenile and adult molluscs was investigated by presenting individual animals with a choice of six chemotypes in three experimental trials: (1) whole plants, (2) nutritive gels containing crushed thyme leaves, and (3) nutritive gels containing a distilled monoterpene as an additive. We found significant and consistent patterns of preference. Adult and immature molluscs preferred the linalol chemotype, and ate carvacrol and thymol-containing foods the least. This preference was more marked when using the gels than the real plants, particularly the monoterpene-based gels, demonstrating the importance of the monoterpene for the choice. Furthermore, molluscs fed exclusively on linalol-containing food gained weight whereas those fed on carvacrol-containing food lost weight. After being fed these exclusive diets both groups showed a significant preference for linalol. These results (1) demonstrate that food choice is based upon the presence of specific monoterpenes and is not learned, (2) suggest that phenolic monoterpenes such as carvacrol are repellent to the animals, and (3) indicate that selective herbivory may play a significant role in the maintenance of the chemical polymorphism of T. vulgaris.1 aLinhart, Y, B1 aThompson, J, D  uhttp://www.scopus.com/scopus/inward/record.url?eid=2-s2.0-0028975168&partnerID=40&rel=R6.5.002512nas a2200229   4500008004100000245007500041210006900116260001400185300001200199490000700211520165300218100002101871700000501892700000501897700003701902700001901939700001501958700001601973700001501989700001802004856026002022       2004                        eng d00aMultiple genetic contributions to plant performance in Thymus vulgaris0 aMultiple genetic contributions to plant performance in Thymus vu  c2004/02//  a45 - 560 v923 a1 Diverse genetic factors can affect plant performance. Here we evaluate how maternal and paternal origin, maternal and offspring sexual phenotype and degree of outcrossing jointly influence performance of gynodioecious Thymus vulgaris. 2 In uniform conditions we quantified size and survival of second-generation (G(2)) offspring produced by selfing and outcrossing on the open-pollinated offspring (G(1)) of G(0) females from four populations that differ in sex ratio, selfing rate and chemical type. We controlled for environmental variation, maternal effects and plant age. 3 Offspring with maternal parents from populations dominated by plants that synthesize phenolic monoterpenes had greater survival and size than those from populations with non-phenolic chemotypes. In addition, outcrossing among populations with pollen donors from non-phenolic populations significantly reduced progeny performance. These results suggest chemotype-mediated local adaptation. 4 The progeny of hermaphrodites showed significant inbreeding depression, which despite the pollination treatment x family and pollination treatment x population interactions, showed no consistent variation in relation to population inbreeding levels. 5 For a given level of outcrossing, the progeny of hermaphrodites showed greater among-family and among-population variation in plant size than those of females. Variation in nuclear restorer gene composition across cytoplasmic backgrounds may cause this variation. 6 T. vulgaris, diverse genetic factors jointly affect performance, a result with general implications for understanding fitness variation in natural populations.1 a.Thompson, JohnD1 a1 a1 a.Linhart, IsabelleLitricoandYanB1 aThompson, J, D1 aTarayre, M1 aGauthier, P1 aLitrico, I1 aLinhart, Y, B  uhttp://muse.lib.auth.gr:9797/com/blackwell-synergy/?MuseHost=www.blackwell-synergy.com&MuseFirst=1&prevSearch=allfield:(thymus+AND+(labiatae+OR+lamiaceae))&StartMuseCookie=I2KBRCK=1;+path=/;+SERVER=10.0.20.25:8080;+path=/;+JSESSIONID=gbdwEZ34tGZWt4uGDaLvr02851nas a2200181   4500008004100000020001400041245011800055210006900173260009400242300001400336490000800350520199200358100001502350700001802365700001502383700001702398856025402415       1995                        eng d  a0029-854900aIntra-specific variation in the inhibitory effects of Thymus vulgaris (Labiatae) monoterpenes on seed germination0 aIntraspecific variation in the inhibitory effects of Thymus vulg  aAffiliation: CNRS,Ctr Ecol.Fonct.& Evolut., Rt Mende,34033 Montpellier, Francec1995/01//  a110 - 1180 v1013 aThe ecological role of plant secondary compounds has received a great deal of attention yet little is known regarding variation in the ecological significance of different compounds produced by a single species. This is particularly pertinent to species where variation in compound presence is under genetic control. In this study we have quantified variation in the inhibitory effects of the six dominant monoterpene oils produced by different genotypes (or chemotypes) of Thymus vulgaris on achene germination of an associated species (Brachy-podium phoenicoides), and seeds of T. vulgaris itself, in controlled experimental conditions. The experiments involved the germination of seeds of the two species with crushed leaves or pure essences of the six chemotypes, i.e. four experimental trials. A significant inhibitory effect against B. phoenicoides was found for both crushed leaves and the range of concentrations of purr oils used in the trial. The two phenolic compounds had a greater effect than the non-phenolic leaves and pure oils. The significant differences between non-phenols and the controls declined faster over time for crushed leaves and low concentrations of the pure essences than did that between the phenolics and the controls. There was a significant inhibitory effect against the germination of T. vulgaris seeds for the crushed leaves and the pure oils, although the contrast between the non-phenols and the phenols was not significant. The effect of the different oils varied depending on the seed source of the thyme seeds used in the trial. This is suggested to be due to differences in the rates of outcrossing among the sampled populations. The effects of the oils on the associated species, B. phoenicoides, were not found to be greater than their effects on the germination of thyme seeds. The results are discussed in the context of a potential role for such inhibitory effects in relation to the onset of rainfall and suitable germination conditions.1 aEscarre, J1 aLinhart, Y, B1 aTarayre, M1 aThompson, JD  uhttp://www.scopus.com/scopus/inward/record.url?eid=2-s2.0-0028977472&partnerID=40&rel=R6.5.0http://muse.lib.auth.gr:9797/com/csa/?MuseHost=www-mi2.csa.com&MuseFirst=1&id=2&recnum=5&SID=f6761d6ffa2f8c20dd10ff73e34434f8&MusePath=/ids70/view_record.php