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Carbon dioxide exchange in lichens: Partition of total CO 2 resistances at different thallus water contents into transport and carboxylation components
Author(s) -
Green T. G. A.,
Snelgar W. P.
Publication year - 1981
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 - 10.1111/j.1399-3054.1981.tb02709.x
Subject(s) - carboxylation , carbon dioxide , thallus , photosynthesis , limiting , chemistry , environmental chemistry , botany , biology , biochemistry , organic chemistry , engineering , catalysis , mechanical engineering
The total resistances to CO 2 uptake by Sticta latifrons Rich, and Pseudocyphellaria amphisticta Kremp. were separated into transport and carboxylation components by calculation after transformation of net photosynthesis rate against CO 2 concentration curves into a linear form. The use of this technique circumvented the problem of measuring the internal CO 2 concentration of the lichen thalli. Both species exhibited an increase in transport resistance at high thallus water contents and an increase in both transport and carboxylation resistances at low water contents. At low and intermediate water contents internal transport resistances were larger than carboxylation resistances when measured at limiting CO 2 concentrations. However, at ambient CO 2 concentrations carboxylation processes were the dominant factors limiting photosynthesis at all, except the high, water contents.