The red edge position and shape as indicators of plant chlorophyll content, biomass and hydric status.

Abstract

Some red edge parameters in the first derivative reflectance curve (wavelength, amplitude and area of the red edge peak) were studied to evaluate plant chlorophyll content, biomassand RelativeWater Content (RWC).Plants of Capsicum annuum and Phaseolus vulgaris under different nitrogen and water availabilities, and plants of Gerbera jamesonii with different hydric status were studied. A high correlation was found between chlorophyll content and the wavelength of the red edge peak (λ_re ), and between LAI (leaf area index)and the amplitude of the red edge peak (dr_{r e} ), but the area of the red edge peak (σ_680–780 nm) was the best estimator of LAI. Thus, red edge was found valuable for assessment of plant chlorophyll concentration and LAI, and therefore nutritional status. Water stress also affected dr_re, but only when the stress was well developed.