Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: "Hypoxylon mammatum toxins: possible involvement in canker development on. | 868s Ann. Sci. For. 1989 46 suppl. 868s-870s Forest Tree Physiology E. Dreyer et al. eds. Elsevier INRA HypoxyIon mammatom toxins possible involvement in canker development on aspen I. Genetet1 J. Pinon1 B. Bodo2 and s. Rebuffat2 1 Laboratoire de Pathologie Forestiere INRACRF Champenoux F-54280 Seichamps and 2 Museum National d Histoire Naturelle Chimie Appliquée aux Corps Organisés CNRS UA401 63 rue Buffon F-75231 Paris Cedex 05 France Introduction Hypoxylon mammatum Wahl. Miller causes a stem canker on aspen Populus tremula and on some poplars of the Taca-hamaca section Pinon 1976 . The disease is characterized by a flattened sunken surface with a yellow orange margin. H. mammatum prevents host callusing. Hubbes 1964 found that diffusible substances from H. mammatum agar cultures inhibited callus formation in wounds on aspen bark. Schipper 1978 and Ster-mer et al. 1984 confirmed the possibility that H. mammatum could produce toxins. These compounds can be isolated by partitioning into various organic solvents and chromatography. Culture age was also supposed to affect the kind and amount of metabolites produced Stermer et al. 1984 . We have isolated and characterized 2 groups of toxins from culture filtrate Bodo et a . 1987 . Optimum secretion was achieved within 6 wk of still culture on wort medium. A technique has been developed to isolate the toxins from the filtrate by adsorption onto a neutral resin Amberlite XAD 4 . Two groups of toxins were separated by elution of the XAD resin with a methanol water gradient hymatoxins first eluted about 40 mg l of filtrate and then neutral metabolites a few mg l . The chemical structures of these substances were determined by spectrometric methods MS IR 1D and 2D NMR . Hymatoxins are unusual diterpene sulfates with a molecular mass of about 400. The other toxin group is constituted of trihydroxytetralones. To provide a clearer understanding of the pathotoxic features of H. mammatum search for and characterization of in .
