THE ABILITY OF 16 ECTOMYCORRHIZAL FUNGI TO INCREASE GROWTH AND PHOSPHORUS UPTAKE OF EUCALYPTUS-GLOBULUS LABILL AND E-DIVERSICOLOR F-MUELL

The effectiveness of 16 fungal isolates in forming ectomycorrhizas and increasing the growth and phosphorus uptake of Eucalyptus globulus La bill. and E. diversicolor F. Muell. seedlings was examined in the glas shouse. Seedlings were grown in yellow sand at 2 phosphorus levels (4 and 12 mg P kg-1 sand). At the time of harvest (100 days), the non-ino culated seedlings and seedlings inoculated with Paxillus muelleri (Ber k.) Sacc. and Cortinarius globuliformis Bougher had a low level of con tamination from an unknown mycorrhizal fungi. Seedlings inoculated wit h Thaxterogaster sp. nov. and Hysterangium inflatum Rodway had develop ed mycorrhizas of the superficial type whereas Hydnangium carneum Wall r. in Dietr., Hymenogaster viscidus Massee & Rodway, Hymenogaster zeyl anicus Petch, Setchelliogaster sp. nov., Laccaria laccata (Scop. ex. F r.) Berk., Scleroderma verrucosum (Vaillant) Pers., Amanita xanthoceph ala (Berk.) Reid & Hilton, Descolea maculata Bougher and Malajczuk and Pisolithus tinctorius (Pers.) Coker & Couch formed typical pyramidal ectomycorrhizas. The dry weight of non-inoculated and inoculated E. gl obulus seedlings at 12 mg P kg-1 sand did not differ, whereas several isolates caused growth depression of E. diversicolor. By contrast, at 4 mg P kg-1 sand growth increases ranged from 0-13 times above that of non-inoculated seedlings. P. tinctorius produced the largest growth i ncrease on both eucalypt species. In general, isolates which developed more extensive mycorrhizas on roots produced the largest growth respo nses to inoculation. Isolates which increased plant growth also increa sed phosphorus uptake by the plant. Seedlings inoculated with L. lacca ta and S. verrucosum retained more phosphorus in their roots than plan ts inoculated with the other fungal isolates.