Diurnal rhythms in stem elongation in Eucalyptus obliqua in relation to temperature and seedling water status

Abstract

Diurnal patterns of stem elongation varied with ambient temperature. Stem elongation was more rapid during the day at lower (20-24°C) day/night temperatures. However, the proportion of night growth increased with increasing temperatures from 30% of the daily total at 20° to 100% at 30°. A decline in both the number and duration of growth flushes appeared to explain the low level of shoot elongation at higher (28° and 30°) day/night temperatures. Under the given experimental conditions, diurnal rhythms in stem elongation reflected ambient temperature rather than seedling water potential.