ibclogo XVI International Botanical Congess


Abstract Number: 5210
Session = 20.10.5


EFFECTS OF ELEVATED CO2 AND TEMPERATURE ON CONIFEROUSECTOMYCORRHIZAS


P. T. Rygiewicz1 and K. J. Martin2, 1U.S. EPA , 2Dynamac Inc., Corvallis, OR 97333, USA.


During 1993-1997, we examined ectomycorrhizal diversity of Douglas-fir seedlings grown in forest soil reconstructed in terracosms. We also categorized ectomycorrhizas on seedlings planted at three elevations in the Oregon Cascades. From spring 1994 to fall 1995, richness increased asymptotically (from 4.2 to 13.1 morphotypes per terracosm in cores to 10 cm depth). Diversity increased faster under elevated temperature (ET). Rhizopogon types dominated terracosm seedlings and were seasonally affected by ET. Cenococcum numbers increased under ET regardless of season, but showed a seasonal effect of CO2 treatment. Compared with ambient CO2 treatments, Cenococcum numbers increased more under elevated CO2 in summer and the reverse was true in winter. Numbers of Rhizopogon tips were similarly affected by CO2.


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