This research was aimed at versifying a mathematical procedure that allows the description of leaf of Kalanchoe (Kalanchoe blossfeldiana Poelln.) and the estimation of its photosynthetically active leaf area starting from a non destructive leaf determination. Seedlings of Kalanchoe cv Gold Jewel were cultivated in irrigated vases with recommended doses for the culture. Three vases were removed weekly from the greenhouse and the plants had their leaves cut, identified and submitted to measures in plant position, longitudinal and transverse length. A total of nine data collection was carried out weekly since 04/04/2003 until blossom. Three plants were sampled weekly and leaf area were calculated using Gauss method (GARCIA & PIEDADE, 1944) implemented in Visual Basic specifically for this purpose. A total of 979 leaves were sampled and the verification of the possibility of using a medium correction factor (FCM) for leaf area independently of its position and growth cycle in the plant, was found out through regression analysis among the values obtained by the standard method (Gauss) and the estimated values for FCM method. The experimental results indicate that the value FCM=1.1134 can be used to estimate leaf area by multiplying length and width leaf values in any phase of the plant and any position of the leaf in the plant.
non destructive method; correction factor; sampling of leaves
