Die Bedeutung der Wachsausblühungen auf Blättern von Kalanchoë pumila BAKER für die Absorption der Globalstrahlung

Abstract

Spectral properties of leaves of Kalanchoë pumila Bakeb were measured for the waverange from 400 to 1350 nm. The significance of the wax bloom for the spectral properties and the absorption of global radiation was determined. The energy absorption of juvenile leaves is increased up to 55% if the wax bloom is removed. The major part of this additional energy input arises from an increased absorptivity in the visible part of the spectrum (400 ... 750 nm), as the result of lowered reflection at the upper surface. For the infrared waverange the wax bloom of both the upper and the lower surface contribute to increase the reflectivity of the upper surface. If the wax bloom is removed only a slight increase of the absorptivity results since the effect caused by lowered reflection is nearly compensated by rised transmission values.