A simple and effective method for quantifying leaf variegation

Abstract

A simple and effective method for quantification of leaf variegation was developed. Using a digital camera or a scanner, the image of a variegated leaf was imported into a computer and saved to a file. Total pixels of the entire leaf area and total pixels of each color within the leaf were determined using an Adobe Photoshop graphics editor. Thus, the percentage of each color's total pixel count in relation to the total pixel count of the entire leaf was obtained. Total leaf area was measured through a leaf area meter; the exact area of this color was calculated in reference to the pixel percentage obtained from Photoshop. Using this method, variegated leaves of 'Mary Ann' aglaonema (Aglaonema x), 'Ornate' calathea (Calathea ornate), 'Yellow Petra' codiaeum (Codiaeum variegatum), 'Florida Beauty' dracaena (Dracaena surculosa), 'Camille' dieffenbachia (Dieffenbachia maculata), and 'Triostar' stromanthe (Stromanthe sanguinea) were quantified. After a brief training period, this method was used by five randomly selected individuals to quantify the variegation of the same set of leaves. The results were highly reproducible no matter who performed the quantification. This method, which the authors have chosen to call the quantification of leaf variegation (QLV) method, can be used for monitoring changes in colors and variegation patterns incited by abiotic and biotic stresses as well as quantifying differences in variegation patterns of plants developed in breeding programs.