Leaf temperatures during radiation frost Part I. Observations

摘要: Abstract Temperatures attained by leaves in natural environments are significantly influenced microhabitat and morphology of the plant. Effects leaf size, height above ground type underlying surface on temperatures Eucalyptus pauciflora E. viminalis seedlings during nights radiation frost were investigated. exposed to clear skies after sunset 1–3°C lower than those adjacent air at all heights except level. Intensity duration sub-freezing diminished with increasing ground. centre larger 0.5–1.5°C for smaller leaves, but tip former similar viminalis. Leaf ∼ when held horizontally compared vertical same height. The corresponding change was between 0.2 0.6°C. At each height, grass dry soil these moist soil. Frequency distributions relating screen isolated determined.