Temperature effect on biomass production and root/shoot biomass ratios in two arctic sedges under controlled environmental conditions

摘要

The effect of differential root and shoot temperatures on biomass production of the arctic sedgesEriophorum vaginatumandCarex bigelowiiwas analyzed under controlled environmental conditions. Both species showed active growth at 2 deg;C root and shoot temperatures although warmer conditions substantially enhanced biomass production. InE.vaginatum, under the optimal 12 deg;C root and 12 deg;C shoot temperature regime, about six times more biomass was produced than under the 2 deg;C conditions. The corresponding temperatures forC.bigelowiiwere 12 deg;C root and 22 deg;C air, although the data did not preclude a higher temperature optimum for this species. The results support the hypothesis that in arctic sedges the root/shoot biomass ratios are small with low root temperatures, i.e., a relatively large fraction of the photosynthate is allocated to leaf production under cold conditions.