Correcting remission and transmission spectra of plant tissue measured in glass cuvettes: a technique.

A method for measuring transmittance and reflectance of plant material in glass cuvettes using a single-beam spectrophotometer with an integrating sphere attachment is described. This method requires extensive processing of the originally measured values as these are distorted by multiple reflections of the diffusely transmitted or reflected light. Most of the theories on light interaction with scattering materials require data processing to meet the theory's prerequisites. Therefore, the complicated evaluation does not restrict the applicability of the method. Special attention is given to the 60 degree/diffuse incidence requirement of the Kubelka-Munk theory. It is argued that the 60 degree/diffuse requirement is not essential for thick scattering layers. It is further stressed that a better knowledge of the optical properties should be of great help in many fields of biology.