tailieunhanh - Báo cáo lâm nghiệp: "in pathways for carbon and nitrogen assimilation in spruce roots under mycorrhization"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: in pathways for carbon and nitrogen assimilation in spruce roots under mycorrhization. | 721s Ann. Sci. For. 1989 46 suppl. 721s-723s Forest Tree Physiology E. Dreyer et al. eds. Elsevier INRA Changes in pathways for carbon and nitrogen assimilation in spruce roots under mycorrhization c. Namysl1 M. Chalot1 B. Dell2 p. Dizengremel1 B. Botton1 and F. Le Tacon3 1 Laboratoire de Physiologie Végétale et Forestiere Université de Nancy I BP 239 54506 Van-dceuvre France 2 Murdoch University School of Biological and Environmental Sciences Murdoch Western Australia 6150 Australia and 3 Centre de Recherches Forestieres de Nancy Laboratoire de Microbiologie Forestiere Champe-noux 54280 Seichamps France Introduction The absorption and assimilation of nitrogen by tree roots are modified by the establishment of an ectomycorrhizal association France and Reid 1983 . Assimilation of inorganic nitrogen occurs in the sheath of the fungus and amino acids are furnished to the host plant roots. A part of photosynthates is diverted to the fungus to be stored or respired and metabolized to provide carbon for amino acid biosynthesis. Some enzyme markers associated with the pathways of nitrogen and carbon metabolism were examined in spruce ectomycorrhizae and in each partner uninfected root and fungus to detect the changes occurring during symbiosis. Materials and Methods The fungus Hebeloma sp. was grown in Pachlewski s medium. Spruce roots Picea abies L. Karsten and mycorrhizae infected with Hebeloma sp. were collected from 4 yr old trees in a tree nursery Merten France . Washed mitochondria were isolated following the method of Gerard and Dizengremel 1988 . Respiration rates of tissues and mitochondria were measured with a Clark type oxygen electrode. KCN and SHAM salicylhydroxamic acid were used to inhibit the electron flow through respectively the cytochrome and the alternative cyanide-resistant pathways. Enzymes were extracted in a medium containing protective agents. Activities were assayed spectrophoto-metrically at 340 nm. Results The respiration of spruce roots was .