INFECTION OF CONTAINERIZED JACK PINE AND BLACK SPRUCE BY LACCARIA SPECIES AND THELEPHORA-TERRESTRIS AND SEEDLING SURVIVAL AND GROWTH AFTER OUTPLANTING

The standard container (Japanese paperpot) and soil mix used in Ontario did not prevent abundant (60 to 70% of short roots) ectomycorrhizal development by Laccaria proxima Boudier or Laccaria bicolor (Maire) Orton after inoculations on jack pine (Pinus banksiana Lamb.) and black spruce (Picea mariana (Mill.) B.S.P.) seedlings. Naturally occurring Thelephora terrestris Ehrh.:Fr., which caused similar proportions of short roots to become ectomycorrhizal on uninoculated control seedlings of both tree species, was apparently prevented from forming ectomycorrhizae on seedlings originally inoculated with L. bicolor and to a lesser extent on those inoculated with L. proxima. Although it could not be proven statistically, it appeared that L. proxima mycorrhizae enhanced the drought tolerance of jack pine seedlings to a greater extent than either T. terrestris or L bicolor.