INFLUENCE OF NITROGEN, PHOSPHORUS, AND POTASSIUM FERTILIZATION ON FOLIAR PIGMENTS IN MUSKMELON PLANTS

The effect of nitrogen (N), phosphorus (P), and potassium (K) fertilization on chlorophyll a and b, carotenes, and anthocyanin was studied in muskmelon plants (Cucumis melo L. cv. Galia) during their biological cycle. Plants were grown under greenhouse conditions using differential fertilization with N, P and K, and irrigation with brackish water. We measured chlorophyll a and b, carotenes, anthocyanin, and total and soluble magnesium (Mg) and iron (Fe) contents. No relationship was found between the rate of fertilizer applied and the content of these pigments. Our results revealed that a relationship does exist between the foliar content of chlorophyll a and Fe, irrespective of the fertilizer treatment applied. However, only a relationship between chlorophyll b and Mg in the P treatments was found. The fact that the chlorophyll content was related to the N and K treatments could be due to a slight deficiency induced by Mg. The phenological stage of specific parameters was studied, resulting in the observation that both chlorophyll a and b and anthocyanins decrease in foliar concentration with age.