Effects of Hebelomaarenosa on growth of red pine seedlings in high-fertility nursery soil in Wisconsin

Abstract

Mycorrhizal colonization and growth of red pine (Pinusresinosa Ait.) inoculated with the fungus Hebelomaarenosa Burdsall, MacFall & Albers were investigated in a highly fertile nursery soil. In greenhouse tests, seedlings became mycorrhizal with H. arenosa when inoculum was incorporated throughout the soil to a 1:256 dilution (v/v). Inoculated seedlings had greater root dry weights and root/shoot ratios than noninoculated seedlings. Seedlings that grew in soil where inoculum had been placed around the seeds had greater root dry weights (at a 1:64 dilution) and shoot dry weights (at a 1:4 dilution) than noninoculated seedlings from unpasteurized or pasteurized soil. Hebelomaarenosa inoculum stimulated increased root and shoot dry weights for 2 years compared with noninoculated seedlings mycorrhizal with indigenous fungi. This study supports the hypothesis that H. arenosa can colonize red pine and cause an increase in growth even in highly fertile nursery soils.