RESPONSES OF JACK PINE AND BLACK SPRUCE SEEDLINGS TO INOCULATION WITH SELECTED SPECIES OF ECTOMYCORRHIZAL FUNGI

Seedlings of jack pine (Pinus banksiana Lamb.) and black spruce (Picea mariana (Mill.) B.S.P.) were inoculated with liquid cultures of fragmented hyphae of 10 species of ectomyocorrhizal fungi and grown in either aseptic culture tubes for 20 weeks or nonaseptic pots for 16 weeks. Seedlings in pots received more total nutrients and produced larger root systems than those in tubes. Four of the fungi produced higher levels of colonization associated with these larger root systems. Short-root density of black spruce was increased compared with that of uninoculated seedlings by inoculation with Laccaria bicolor (Maire) Orton, Hebeloma cylindrosporum Romagnesi, or Thelephora terrestris Ehrh. ex Fr. Colonization of jack pine by Rhizopogon rubescens (Tul.) Tulasne, L. bicolor, H. cylindrosporum, or Pisolithus tinctorius (Pers.) Coker & Couch resulted in greater short-root densities than in uninoculated controls. Inoculation of potted black spruce with Laccaria proxima Boudier resulted in larger shoot weights and those inoculated with H. cylindrosporum had smaller root weights than did uninoculated seedlings. Both fungi resulted in increased shoot/root dry-weight ratios in black spruce. In contrast with black spruce, seedling weights were not affected by inoculation of jack pine with the same fungal species. However, inoculation of jack pine with R. rubescens resulted in a significantly higher shoot/root dry-weight ratio.