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

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: "Effects of decline and/or air pollution on the terpene metabolism of Picea abies needles. | 864s Ann. Sci. For. 1989 46 suppl. 864s-867s Forest Tree Physiology E. Dreyer et al. eds. Elsevier INRA Effects of decline and or air pollution on the terpene metabolism of Picea abies needles A. Saint-Guily Laboratoire de Physiologie Cellulaire Végétale CNRS UA568 Université de Bordeaux I 33405 Talence Cedex France Introduction The terpene metabolism mevalonic acid pathway is a secondary metabolism present in all plants. Terpenes are elaborated by successive condensation of isoprene units C5 . c1o and c15 terpene molecules are the main constituents of the volatile oils. These volatile terpenes are formed in secretory systems. Leucoplasts nongreen plastids Garde 1984 are involved in their synthesis Gleizes eta . 1983 . In conifer needles these plastids are localized in the epithelial cells of the subepider-mal resin ducts. In Picea abies needles the secretory ducts are longitudinal and discontinuous. Forest decline is an important problem which appears in several countries in Europe and North America McLaughlin 1985 . Most of the damaged forests are coniferous forests containing mainly spruce Picea . Among the potential causes of forest decline air pollution has received particular attention McLaughlin 1985 . Previous studies have shown that the resin content of pine tissues greatly increases after mechanical or chemical injuries wounding Vassiliev and Garde 1976 infestation by insects and infection by fungi Cheniclet 1987 or treatment with herbicides Brown and Nix 1975 . The intention of this study was to elucidate a possible relationship between the stress factors and a variation in terpene metabolism. Materials and Methods Different samples of needles were collected in the spruce P. abies stands which were located in the Donon forest where 3 decline classes were defined with respect to needle loss class 2 0-10 needle loss class 3a 10-20 and class 3b 35-50 with yellowish chlorosis . Needles of 3 consecutive yr from about 12 trees of each decline class were .