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THE INTERDEPENDENCE OF PHOTON IRRADIANCE AND FREE CARBON DIOXIDE OR BICARBONATE CONCENTRATION ON THE PHOTOSYNTHETIC COMPENSATION POINTS OF FRESHWATER PLANTS
Author(s) -
MABERLY S. C.
Publication year - 1983
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.1469-8137.1983.tb02686.x
Subject(s) - irradiance , photosynthesis , compensation point , bicarbonate , carbon dioxide , chemistry , phytoplankton , environmental science , macrophyte , total inorganic carbon , compensation (psychology) , atmospheric sciences , environmental chemistry , ecology , physics , biology , optics , nutrient , transpiration , organic chemistry , psychology , biochemistry , psychoanalysis
S ummary The free CO 2 (CO 2 *) and HCO 3 − compensation points of eight freshwater macrophytes and four phytoplankters were measured using a pH‐drift technique developed by Allen and Spence (1981). Below a critical photon irradiance, which was about that at which net photosynthesis was half‐maximal, CO 2 * and HCO 3 − compensation points increased with decreasing photon irradiance. However, the CO 2 * compensation point of two species that were able to use HCO 3 − were little or not affected by photon irradiance. The light compensation point increased at low CO 2 * or HCO 3 − concentrations. The simultaneous generation by phytoplankton of light and carbon depletion could have a large deterimental effect on macrophyte performance.