Some Optical Properties of Leaves of Eight Temperate Forage Grasses

Two instruments are described for the measurement of the reflectionand transmission of radiation by grass leaves. The first ofthese was used to measure the spatial distribution of reflectedand transmitted light. It was demonstrated that reflection wasinfluenced by the epidermal structure of a leaf, and that theimportance of this layer increased with increasing angle ofincidence. The second instrument was used to compare the reflectance andtransmittance of leaves of different ages taken from eight temperategrasses. There were significant differences between the grassesin leaf transmittance, and generally the young emerging leafhad a greater transmittance than the fully-expanded leaves.The differences in leaf transmittance could be related to differencesin specific leaf weight. There were no significant differencesbetween the species and varieties in leaf reflectance.