tailieunhanh - Báo cáo lâm nghiệp: "Changing electrophoretic patterns of glutamate dehydrogenases and aspartate aminotransferases in a few tree species under the influence of ectomycorrhization"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Changing electrophoretic patterns of glutamate dehydrogenases and aspartate aminotransferases in a few tree species under the influence of ectomycorrhization. | 718s Ann. Sci. For. 1989 46 suppl. 718S-720S Forest Tree Physiology E. Dreyer etal. eds. Elsevier INRA Changing electrophoretic patterns of glutamate dehydrogenases and aspartate aminotransferases in a few tree species under the influence of ectomycorrhization B. Botton1 M. Chalot1 and B. Dell2 Université de Nancy I Faculte des Sciences Laboratoire de Physiologic Végétale et Forestiere BP 239 54506 Vandceuvre-les-Nancy Cedex France and . 2 Murdoch University School of Biological and Environmental Sciences Murdoch Western Australia 6150 Australia Introduction Numerous studies have demonstrated the widespread existence of two systems for nitrogen assimilation in plants and microorganisms the glutamate dehydrogenase GDH pathway and the glutamine synthetase GS glutamate synthase GOGAT cycle. While the GS GOGAT pathway is operative in higher plants Lea and Miflin 1974 ammonia assimilation in fungi generally occurs via the GDH pathway Pateman and Kinghorn 1975 although some non-mycorrhizal fungi seem capable of utilizing the alternative glutamine synthetase glutamate synthase route Kusnan etal. 1987 . In mycorrhizal associations preliminary data have shown that the fungal pathways of nitrogen assimilation in beech-mycorrhizas are modified by the establishment of the symbiosis and that glutamate dehydrogenase plays a minor role in this process Martin et al. 1986 . Taking these observations into account we studied a few ectomycorrhizal associations focusing on GDH and aspar tate aminotransferase AAT an enzyme which converts glutamate into aspartate. Materials and Methods Norway spruce Picea excelsa roots and Hebeloma sp. ectomycorrhizas were obtained from 4 yr old plants grown under nursery conditions. Douglas fir Pseudotsuga douglasii roots either non-mycorrhizal or ectomycorrhizal with Laccaria laccata strain s 238 were collected from 1 yr old seedlings grown under nursery conditions. Beech Fagus sylvatica roots and Paxillus involutes Naudet strain ectomycorrhizas as .