Variability in ectomycorrhizal development and growth among isolates of Pisolithustinctorius as affected by source, age, and reisolation

摘要: Twenty-one isolates of Pisolithustinctorius (Pers.) Coker and Couch of different ages and from different tree hosts and world locations were initially tested for ectomycorrhizal development on Pinustaeda L. seedlings in a growth room. Three oak isolates from the United States and seven pine isolates from the United States, Brazil, and Australia (1 – 17 years old) formed few or no ectomycorrhizae. Eleven remaining pine isolates (1 – 6 years old) collected in Taiwan, France, and nine locations in the United States formed abundant ectomycorrhizae.Reisolates were obtained from the above ectomycorrhizae formed by the original isolates. In pure culture on agar medium, most original isolates grew as fast or faster than the companion reisolates. Individual isolates differed greatly, however, in growth response at various temperatures; these differences were unrelated to age of culture or reisolation.In a nursery experiment, there were large differences among eight isolates and nine reisolates in degree of ectomycorrhizal development on P. taeda seedlings. Reisolation significantly improved ectomycorrhizal development of three original isolates (4 – 7 years old) but not others. There was no relationship between rate of growth in agar medium and capacity of isolates or reisolates to form ectomycorrhizae. The significance of age, host origin, and world location on variation in Pisolithustinctorius is discussed.Vingt et un isolais de Pisolithustinctorius (Pers.) Coker et Couch d'âges différents, provenant d'arbres-hôtes et de lieux géographiques distincts, sont d'abord étudiés quant à leur développement ectomycorhizien sur des semis de Pinustaeda L. en chambre de croissance. Trois souches isolées à partir de chênes aux États-Unis et sept souches isolées à partir de pins aux États-Unis, au Brésil et en Australie (agées de 1 à 17 ans) ne forment que peu ou aucune ectomycorhize. Les 11 autres souches (agées de 1 à 6 ans) qui proviennent de Taiwan, de France et de neuf endroits aux États-Unis, forment de nombreuses ectomycorhizes.