Báo cáo khoa học: Effects of decline and/or air pollution on the terpene metabolism of Picea abies needles

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Báo cáo khoa học: "Effects of decline and/or air pollution on the terpene metabolism of Picea abies needles"Effects of decline and/or air pollutionon the terpene metabolism of Picea abies needlesA. Saint-Guily CNRS UA568, Unii de Bordeaux I, 33405 ersitd lLaborafoire de Physiologie Cellulaire V6g6tale,Talence Cedex, FranceIntroduction by fungi (Cheniclet, 1987) or treatment with herbicides(Brown and Nix, 1975). The intention of this study was to eluci-The terpene metabolism (mevalonic acid date a possible relationship between thepathway) is a secondary metabolism pres- stress factors and variation in terpeneent in all plants. Terpenes are elaborated a metabolism.by successive condensation of isopreneunits (C C and C terpene molecules 15 ). 5 10are the main constituents of the volatileoils. These volatile terpenes are formed insecretory systems. Leucoplasts, non- Materials and Methodsgreen plastids (Carde, 1984), are involvedin their synthesis (Gleizes et al., 1983). In Different samples of needles were collected inconifer needles, these plastids are local- the spruce (P. abies) stands which were locatedized in the epithelial cells of the subepider- in the Donon forest where 3 decline classesmal resin ducts. In Picea abies needles, were defined with respect to needle loss: classthe secretory ducts are longitudinal and 2 (0-10% needle loss), class 3a (10-20%) and class 3b (35-50% with yellowish chlorosis).discontinuous. Needles of 3 consecutive yr from about 12 trees Forest decline is an important problem of each decline class were collected. The otherwhich appears in several countries in samples of 5 yr old clones (lac de Constance (LC), G6rardmer (GER), Istebna (IST) wereEurope and North America (McLaughlin, collected in the open top chambers of Montar-1985). Most of the damaged forests are don and Donon. These plants were placedconiferous forests containing mainly under controlled conditions of air pollutionspruce (Picea). Among the potential which were equivalent to the pollution recorded in the Donon forest. The 3 clones were placedcauses of forest decline, air pollution has in air-filtered open top chambers or fumigatedreceived particular attention (McLaughlin, with ozone (0 or sulfur dioxide (S0 alone or ) 3 ) 21985). Previous studies have shown that a mixture. In Montardon, a mobile roof protectsthe resin content of pine tissues greatly the trees from the rain.increases after mechanical or chemical Cytological observations were made with aninjuries: wounding (Vassiliev and Carde, electron microscope. RuBPCase was localized1976), infestation by insects and infection on ultrathin sections using immunogold labelingtechniques (Shaw and Henwood, 1985). Theleucoplastidial volume density (LVD) (% of thecell volume occupied by leucoplasts) was esti-mated using a morphometric technique (Weibel,1969). For analytical studies, oxygenated and hydro-carbon terpene fractions were separated on asilica column after pentane extraction and ana-lyzed with a gas chromatograph, using an apo-lar capillary column (Belingheri et al., 1988). A’desorption concentration injection’ system(DCI, Delsi, France) was also used. About 5needles were inserted into a heating block. Thevolatile compounds were swept by a carrier gas For each pair of classes the sample statistic T’ wasand tra ...