ISSN:
1399-3054
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Plantago lanceolata L. seedlings were grown in sand microcosm units over a 43-day experimental period under two CO2 regimes (800 or 400 µmol mol−1) to investigate the effect of elevated atmospheric CO2 concentration on carbon partitioning and exudate release. Total organic carbon (TOC) content of the collected exudate material was measured throughout the experimental period. After 42 days growth the seedlings were labelled with [14C]-CO2 and the fate of the label within the plant and its release by the roots monitored. Elevated CO2 significantly (P ≤ 0.001) enhanced shoot, root and total dry matter production although the R:S ratio was unaltered, suggesting no alteration in gross carbon partitioning. The cumulative release of TOC (in mg C) over 0-42 days was unaltered by CO2 treatment however, when expressed as a percentage of net assimilated C, ambient-grown plants released a significantly (P≤ 0.001) higher percentage from their roots compared to elevated CO2-grown plants (i.e. 8 vs 3%). The distribution of 14C-label was markedly altered by CO2 treatment with significantly (P≤ 0.001) greater per cent label partitioned to the roots under elevated CO2. This indicates increased partitioning of recent assimilate below-ground under elevated CO2 treatment although there was no significant difference in the percentage of 14C-label released by the roots. Comparison of plant C budgets based on 14C-pulse-chase methodology and TOC measurements is discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1034/j.1399-3054.1998.1030216.x
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