In vitro synthesis of ectomycorrhizas on Casuarinaceae with a range of mycorrhizal fungi

Abstract

Eleven species of mycorrhizal fungi, selected from stands of either Eucalyptus spp., Allocasuarina spp. or Pinus radiata D. Don were tested in an aseptic system for their abilities to initiate ectomycorrhiza with Allocasuarina littoralis (Salisb.) L. Johnson, Casuarina equisetifolia ssp. equiselifolia L. and C. cunninghamiana Miq. Elaphamyces sp., Hysterangium sp., Laccaria laccata (Scop ex Fr.) Bk. & Br., Pisolithus tinctorius (Pers.) Coker & Couch, Scleroderma sp. and Thelephora terrestris (Ehrh.) Fr. formed ectomycorrhizas on all three hosts. Amanita sp. formed ectomycorrhizas on A. littoralis and C. cunninghamiana but not on C. equisetifolia. Paxillus involutus (Batch ex Fr.) Fr. formed ectomycorrhizas on A. littoralis only. P. tinctorius also formed ectomycorrhizas with C. obesa Miq. Rhizapogon luteolus Fr. & Nord, Suillus granulatus (L. ex Fr.) Kuntze and S. piperatus (Bull ex Fr.) O. Kuntze colonized the rhizosphere of Casuarinaceae but did not form ectomycorrhizas. The comparative intensity of ectomycorrhizal infection by P. tinctorius and L. laccata was assessed on four host species. Infection intensity ranged from 13 to 70%, of laterals infected and decreased for both fungal species in the order: A. littoralis > Eucalyptus pilularis Smith > C. equisetifolia > C. cunninghamiana. An exogenous supply of glucose induced greater and sometimes earlier, ectomycorrhizal infection of A. littoralis, C. equisetifolia and C. cunninghamiana by P. tinctorius and L. laccata than that in the absence of glucose. The optimum glucose level for these fungi and hosts in this synthesis system was 750 μg glucose (g soil)−1. Copyright © 1991, Wiley Blackwell. All rights reserved