Optics of a bifacial leaf .1. A novel combined procedure for deriving the optical parameters

A novel experimental-theoretical procedure, deriving optical parameters of a bifacial leaf, is presented and analyzed. Its theoretical basis is the four-flux approximation of the radiative transfer theory. Its experimental basis is three-dimensional measurements of internal radiances at different depths and in different directions within a leaf by using optical microprobes. The intrinsic instrumental error of the microprobe measurements is accounted for by a special correcting theory, The treatment yields the spectral curves for attenuation, scattering and absorption coefficients as well as for the asymmetry of scattering in both palisade and spongy tissue layers. The values of obtained optical parameters were verified by comparing calculated transmission and remission of a leaf with those measured with the integrating sphere. It is concluded that the treatment provides a sound basis for the analysis of the light microenvironment as a function of leaf structure and the nature of incident light.