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Photorespiration and Glycolate Metabolism in Tobacco Leaves 1
Author(s) -
Moss Dale N.
Publication year - 1968
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1968.0011183x000800010021x
Subject(s) - photorespiration , photosynthesis , biology , metabolism , respiration , biochemistry , botany
The stimulating effect of light on the evolution of CO 2 from tobacco leaves into CO 2 ‐free air was suppressed by inhibition of glycolate oxidase with α‐hydroxy‐2‐pyridinemethanesulfonic acid. The inhibitor strongly inhibited photosynthesis at both 25 and 35 C. The CO 2 compensation concentration increased indefinitely for leaves treated with inhibitor. Glycolate accumulation in leaves treated with inhibitor was strongly dependent on inhibitor concentration and light intensity and was linear with time up to one hour. Temperature for growth or during the experiments had little effect on accumulation. The possible internal CO 2 from the oxidation of glycolate calculated on the basis of glycolate accumulation under optimal conditions indicates that photorespiration from glycolate as a substrate may be at least 2‐fold dark respiration. Although the possible rate of respiration from glycolate metabolism was large, it was not sufficient to account for the differences in photosynthesis between maize and tobacco on the assumption that this difference was due to internal recycling of CO 2 in tobacco.