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Commissioned Review. Carbon: freshwater plants

Plant, Cell and Environment

By:
and
DOI: 10.1111/j.1365-3040.1992.tb01653.x

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Abstract

δ13C values for freshwater aquatic plant matter varies from −11 to −50‰ and is not a clear indicator of photosynthetic pathway as in terrestrial plants. Several factors affect δ13C of aquatic plant matter. These include: (1) The δ13C signature of the source carbon has been observed to range from +1‰ for HCO3− derived from limestone to −30‰ for CO2 derived from respiration. (2) Some plants assimilate HCO3−, which is –7 to –11‰ less negative than CO2. (3) C3, C4, and CAM photosynthetic pathways are present in aquatic plants. (4) Diffusional resistances are orders of magnitude greater in the aquatic environment than in the aerial environment. The greater viscosity of water acts to reduce mixing of the carbon pool in the boundary layer with that of the bulk solution. In effect, many aquatic plants draw from a finite carbon pool, and as in terrestrial plants growing in a closed system, biochemical discrimination is reduced. In standing water, this factor results in most aquatic plants having a δ13C value similar to the source carbon. Using Farquhar's equation and other physiological data, it is possible to use δ13C values to evaluate various parameters affecting photosynthesis, such as limitations imposed by CO2 diffusion and carbon source.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Commissioned Review. Carbon: freshwater plants
Series title:
Plant, Cell and Environment
DOI:
10.1111/j.1365-3040.1992.tb01653.x
Volume
15
Issue:
9
Year Published:
1992
Language:
English
Publisher:
Wiley
Contributing office(s):
Western Ecological Research Center
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Plant, Cell and Environment
First page:
1021
Last page:
1035
Number of Pages:
15