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Contrasting effects of elevated CO 2 on the root and shoot growth of four native herbs commonly found in chalk grassland
Author(s) -
FERRIS RACHEL,
TAYLOR GAIL
Publication year - 1993
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1993.tb03934.x
Subject(s) - lotus corniculatus , shoot , plantago , botany , grassland , plantaginaceae , biomass (ecology) , biology , horticulture , chemistry , agronomy
SUMMARY The aim of this study was to investigate the impact of ambient (345 μl l −1 ) and elevated (590 μl l −1 ) CO 2 on the root and shoot growth of four native chalk grassland herbs: Sanguisorba minor Scop, (salad burnet), Lotus carniculatus L. (birdsfoot trefoil), Anthyllis vulneraria L. (kidney vetch) and Plantago media L. (hoary plantain). Elevated CO 2 had contrasting effects on both shoot and root growth of the four species studied. Both leaf expansion and production were stimulated by elevated CO 2 for S. minor, L. corniculatus and P. media , whilst for A. vulneraria , only leaflet shape appeared to be altered by elevated CO 2 , with the production of broader leaflets, compared with those produced in ambient CO 2 . After 100 d shoot biomass was enhanced in elevated CO 2 for S. minor and L. corniculatus , whilst there was no effect of elevated CO 2 on shoot biomass for A. vulneraria or P. media . Contrasting effects of CO 2 were also apparent for measurements of specific leaf area (SLA), which increased for L. corniculatus , decreased for A. vulneraria and remained unaltered for S. minor and P. media in elevated compared with ambient CO 2 . Elevated CO 2 also had contrasting effects on both the growth and morphology of roots. The accumulation of root biomass was stimulated following exposure to elevated CO 2 for S. minor and L. corniculatus whilst there was no effect on root biomass for A. vulneraria or P. media . Root length was measured on three occasions during the 100 d and revealed that exposure to elevated CO 2 promoted root extension in S. minor, L. corniculatus and P. media , but not in A. vulneraria . Specific root length (SRL, length per unit dry weight) was increased in elevated CO 2 for one species, P. media , whilst the root to shoot ratio of all four species remained unchanged by CO 2 . These results show that four native herbs differ in their response to CO 2 , suggesting that the structure of this plant community may be altered in the future.