Optical properties and nondestructive estimation of anthocyanin content inplant leaves

Absorption and reflectance spectra of maple (Acer platanoides), cotoneaster (Cotoneaster alaunica), dogwood (Cornus alba) and pelargonium (Pelargonium zonale) leaves with a wide range of pigment content and composition were s tudied in visible and near-infrared spectra in order to reveal specific ant hocyanin (Anth) spectral features in leaves, Comparing absorption spectra o f Anth-containing and Anth-free leaves with the same chlorophyll (Chl) cont ent, absorption spectra of Anth in leaves were derived. The main spectral f eature of Anth absorption in vivo was a peak around 550 nm; the peak magnit ude was closely related to Anth content. A quantitative nondestructive tech nique was developed to subtract Chl contribution to reflectance in this spe ctral region and retrieve Anth content from reflectance over a wide range o f pigment content and composition, Anth reflectance index in the form ARI = (R-550)(-1) - (R-700)(-1) where (R-550)(-1) and (R-700)(-1) are inverse re flectances at 550 and 700 nm, respectively, allowed an accurate estimation of Anth accumulation, even in minute amounts, in intact senescing and stres sed leaves.