Visible light reflectance, transmittance, and absorptance of differently pigmented cotton leaves

Abstract

Spectrophotometrically measured light reflectance and transmittance, and calculated absorptance over the 0.45–0.70 μm waveband (WB) of four differently pigmented cotton ( Gossypium hirsutum L.) leaves are compared. Leaf color appearances were green (G), common red (CR), light red or bronze (B), and yellow-green (YG). The G and YG leaves (chlorophylls and carotenoid) had about the same reflectance and transmittance peaks at the 0.55-μm wavelength (WL), although YG leaves had much higher reflectance and transmittance than G leaves. Anthocyanin pigment manifestation in CR, B, and YG leaves occurred at about the 0.60-μm WL. The red light (0.65-μm) absorptances of leaves in decreasing magnitude were: CR, G, YG, and B. There was little effect on blue light (0.45-μm) absorptance. Spectral responses of cotton leaves were very sensitive to either their masked or predominant pigmentation over the 0.45–0.70-μm WBs. The possible importance of leaf pigmentation to LANDSAT-D's thematic mapper, visible light WBs is discussed.