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Carboxydismutase and Phosphoenolpyruvate Carboxylase Activities From Leaves of Some Plant Species from the Northern Mojave and Southern Great Basin Deserts
Author(s) -
Wallace A.,
Hale V. Q.,
Kleinkopf G. E.,
Huffaker R. C.
Publication year - 1971
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1933818
Subject(s) - phosphoenolpyruvate carboxylase , crassulacean acid metabolism , biology , photosynthesis , botany , chenopodiaceae , zygophyllaceae , pyruvate carboxylase , phosphoenolpyruvate carboxykinase , enzyme , biochemistry
Of 14 xerophytic plant species studied, only two (members of the Chenopodiaceae) exhibited high phosphoenolpyruvate (PEP) carboxylase and low carboxydismutase activities. Three other members of the Chenopodiaceae exhibited carobyxlase activities characteristic of both the C_4—dicarboxylic acid pathway and the Calvin cycle in the same species. Activities range from high PEP carboxylase and moderately high carboxydismutase to, conversely, high carboxydismutase and moderately high PEP carboxylase activity, including moderately high levels of nearly equal activities of each enzyme. Hence, gradations between extremes of the two photosynthetic systems can occur in the same species. Members of three other families (Ephedraceae, Zygophyllaceae, and Liliaceae) had carboxylase activities characteristic of both photosynthetic systems in the same species. The enzymatic activity of plants which continue to grow during hot summers was characteristic of either the C_4—dicarboxylic acid pathway or of both photosynthetic pathways.