Sampling the most recently mature leaf was realized 15 days after the appearance of the flower bud, to determine the concentration of N, P, K, Ca and Mg. Nitrogen concentration was evaluated by micro-Kjeldahlmethod. The concentrations of P, K, Ca, and Mg were determined using inductively coupled plasma atomic emission spectroscopy (ICP-AES) according to Alcántar and Sandoval (1999).