© 2004 Heron Publishing—Victoria, Canada
Allocation of 14C-carbon in two species of larch seedlings infected with ectomycorrhizal fungi
L. Y. Qu (1), T. Shinano (2), A. M. Quoreshi (3, 4), Y. Tamai (1), M. Osaki (1) and T. Koike (3, 5)
1. Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan / 2. Creative Research Initiative “Sousei” (CRIS), Hokkaido University, Sapporo, 060-0808, Japan / 3. Hokkaido University Forests, FSC, Sapporo 060-0809, Japan / 4. Forest Biology Research Centre, University of Laval, Sainte-Foy, QC, GIK 7P4, Canada / 5. Corresponding author (tkoike@exfor.agr.hokudai.ac.jp) / Received December 23, 2003; accepted May 9, 2004; published online October 1, 2004
Summary
The flow of labeled carbon in ectomycorrhizal and non-ectomycorrhizal seedlings of Japanese larch (Larix kaempferi Sarg.) and its F1 hybrid (Larix gmelinii Rupr. × L. kaempferi) was studied. Larch seedlings were grown in a greenhouse for 110 days with larch forest soil (FM) or Suillus grevillei (SM) inoculum, or in the absence of ectomycorrhizal fungi (NM). Shoots of colonized and NM seedlings were exposed to a pulse
of 14CO2 for 1 h under natural light. Seedlings were harvested following 0, 6 and 24 h of exposure to 14CO2. At the final harvest, SM seedlings of Japanese larch and hybrid larch allocated 2.6 and 2.5% more 14C, respectively, to roots than NM seedlings. In contrast, FM seedlings of Japanese larch and hybrid larch allocated 6.5 and
18.0% more 14C, respectively, to the stem than NM seedlings. Of the total 14C detected in needle, stem and root fractions, FM and SM seedlings allocated a greater proportion than NM seedlings, perhaps
because FM and SM seedlings had significantly (P < 0.05) higher photosynthetic rates than NM seedlings. As a result, FM and SM seedlings had greater dry masses than NM seedlings.
Concentrations of nitrogen and phosphorus in FM and SM seedlings were significantly (P < 0.05) higher than in NM seedlings, as was stomatal conductance.
Keywords:
14C, hybrid larch, Japanese larch, photosynthate allocation, Suillus grevillei.
