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Effect of elevated CO 2 on carbon partitioning and exudate release from Plantago lanceolata seedlings
Author(s) -
Hodge Angela,
Millard Peter
Publication year - 1998
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1034/j.1399-3054.1998.1030216.x
Subject(s) - exudate , plantago , shoot , chemistry , zoology , total organic carbon , horticulture , microcosm , carbon fibers , botany , biology , environmental chemistry , materials science , composite number , composite material
Plantago lanceolata L. seedlings were grown in sand microcosm units over a 43‐day experimental period under two CO 2 regimes (800 or 400 µmol mol −1 ) to investigate the effect of elevated atmospheric CO 2 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 [ 14 C]‐CO 2 and the fate of the label within the plant and its release by the roots monitored. Elevated CO 2 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 CO 2 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 CO 2 ‐grown plants (i.e. 8 vs 3%). The distribution of 14 C‐label was markedly altered by CO 2 treatment with significantly (P≤ 0.001) greater per cent label partitioned to the roots under elevated CO 2 . This indicates increased partitioning of recent assimilate below‐ground under elevated CO 2 treatment although there was no significant difference in the percentage of 14 C‐label released by the roots. Comparison of plant C budgets based on 14 C‐pulse‐chase methodology and TOC measurements is discussed.