title: Adaptation and acclimation of higher plants at the enzyme level: Latitudinal variations of thermal properties of NAD malate dehydrogenase in Lathyrus japonicus Willd. (Leguminosae).
abstract: Thermal properties of NAD malate dehydrogenase were investigated in 8 clonal populations of Lathyrus japonicus Willd. collected over a 16° latitudinal gradient in eastern North America. Clones from warmer summer sites had higher activation energies (Ea) and enhanced thermostability for the enzyme under three contrasting growth temperature regimes. A strong component of acclimation was associated with Ea, but not with thermostability. Activity levels of the enzyme were higher in warm-adapted genotypes but cold-acclimated plants had similar low levels of specific activity. The clones were differentiated by ordination in a pattern related to climatic origin.
authors.affiliation: Département des Sciences biologiques, Université de Montréal, 90 Vincent d'Indy, H3C 3J7, Montréal, P.Q., Canada.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Simon