Adaptation and Acclimation of Higher Plants at the Enzyme Level: Kinetic Properties of NAD Malate Dehydrogenase in Three Species of Viola
1986; Wiley; Volume: 74; Issue: 1 Linguagem: Inglês
10.2307/2260346
ISSN1365-2745
AutoresJean‐Pierre Simon, Christiane Charest, M.-J. Peloquin,
Tópico(s)Chemical synthesis and alkaloids
ResumoSUMMARY (1) Kinetic properties of NAD malate dehydrogenase (MDH) were investigated in three species of Viola: V. blanda, V.fimbriatula and V. sororia. Plants from three clones of each species, collected over the latitudinal range of each species in eastern North America, were acclimated under controlled conditions at three different thermoperiods: 7/15 IC, 15/22 IC and 22/28 OC. (2) The apparent Michaelis constant (Km.) for oxalacetic acid increased with rising assay temperatures, and cold acclimation reduced Km values at low assay temperatures in plants of the cold-adapted Quebec clones of V. blanda and V. sororia acclimated at 7/15 OC and 15/22 OC. (3) The Vm.ax/Km ratios for MDH were higher at assay temperatures closely related to growth conditions although this trend was expressed differentially depending on the species or the clone analysed. (4) Differential trends were observed in between-species comparisons and can be correlated with the microclimate in the habitat of the species.
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