It was found that the radiation reflected by adaxial surface of leaf was elliptic polarization with maximum near Brewster. The ellipticity of reflected by leaves radiation increased with the increasing of mesophyll air spaces and the decreasing of leaf chlorophyll concentration. It can be explained that the non-polarized fraction of light from internal structure depends on the leaf pigments concentration and the quantity of air spaces in mesophyll.
It is shown that the largest differences in the angular distribution and meanings of the polarization characteristics of radiation reflected by different plant's leaves are observed for leaves illuminated at the angle of 55 degrees by a He-Ne laser radiation ((lambda) equals 0.63 micrometer) linearly polarized in the plane of incidence. It has been revealed that radiation reflected by a leaf becomes elliptically polarized at observation angles of 55 degrees plus or minus 10 degrees. The ellipticity of radiation reflected by leaves depends on the leaf thickness and the position of the top or bottom of the leaf surface relative to the direction of illumination.