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The interactive effects of light and inorganic carbon on aquatic plant growth
Author(s) -
MADSEN T. V.,
SANDJENSEN K.
Publication year - 1994
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.1994.tb00324.x
Subject(s) - elodea canadensis , macrophyte , total inorganic carbon , photosynthesis , carbon fibers , light intensity , aquatic plant , botany , dissolved organic carbon , acclimatization , biology , chemistry , carbon dioxide , environmental chemistry , ecology , materials science , physics , composite number , optics , composite material
Submerged aquatic macrophytes grow across a wide, often coupled, range of light and inorganic carbon availabilities, and each single factor influences photosynthesis and acclimation. Here we examine the interactive effects of light and inorganic carbon on the growth of Elodea canadensis and Callitriche cophocarpa. The plants were grown in the laboratory at a range of light intensities (0–108 μmol m −2 s −1 ) and four inorganic carbon regimes in a crossed factorial design. Plant growth rates, measured over 3–4 weeks of incubation, increased in response to increasing light intensity and inorganic carbon availability, and significant interactive effects were observed. The light‐use efficiency for growth at low light increased 2‐fold for Callitriche and 6‐fold for Elodea between the lowest and highest inorganic carbon concentrations applied. Also, the growth rate at the highest light intensity increased with inorganic carbon availability, but the relative increase was smaller than at low light. Both species acclimated to the light and carbon regime such that the chlorophyll content declined at low and high light intensities and the initial slopes of the photosynthetic CO 2 and HCO 3 − response curves declined at high levels of CO 2 . Callitriche responded less markedly than Elodea to changing inorganic carbon availability during growth, and the initial slope of the photosynthetic HCO 3 − response curve, in particular, was greatly reduced (>90%) in Elodea by high CO 2 . It is suggested that the coupled responses of aquatic macrophytes to light and inorganic carbon influence their ability to develop dense stands at high light in shallow water and to extend to greater depths in waters rich in inorganic carbon.