The Effect of Temperature on Vegetative Growth in Climatic Races of Dactylis glomerata in Controlled Environments

Abstract

The growth patterns in two natural populations of Dactylis glomerata from contrasting climatic regions, Norway and Portugal, were studied at four constant temperatures (5, 10, 20, and 30o C) in a 16-h photoperiod. Marked changes in relative growth-rate at different temperatures were positively correlated with changes in both net assimilation rate and leaf-area ratio, whereas differences between the populations in the relative growth-rate were the result of differences in net assimilation rate, and were negatively correlated with differences in leafarea ratio. The changes in leaf-area ratio at different temperatures were correlated with changes in leaf morphology and distribution of assimilates within the plant. The possible adaptive advantage of these vegetative growth patterns is discussed in relation to the survival of the plants in the original environments.