Effects of nitrogen, phosphorus and potassium treatments on phosphorus fractions in melon plants
1996
Valenzuela, J.L. | Ruiz, J.M. | Belakbir, A. | Romero, L.
The effects of nitrogen (N), phosphorus (P), and potassium (K) treatments on the P fractions in muskmelon plants (Cucumis melo L. cv. Galia) are presented. Plants were grown under greenhouse conditions with different NPK treatments. Leaves were sampled every two weeks from the middle third of each plant. After washing in nonionic soap and distilled water, the leaves were dried in an oven at 70 degrees C and then ground. The foliar contents of several P fractions [inorganic P (Pinorg), organic P, lipid P, RNA-P, DNA-P, and proteic P] were determined. Inorganic and organic P were found to be the major fractions. For both N and K treatments, the Pinorg content increased, although at high doses (N24 and K30), there was a reduction in leaf content. With the P treatments, the contents of the fractions increased steadily, but with the highest doses (P15 and P20), the leaf content of the fractions was very similar, indicating a saturation phenomenon. Evolution of the fractions over tune showed similar behavior. Constant export occurred in all the fractions, with the only difference between them being in the intensity of the export effect. The data presented highlight the need to consider the effects of NPK treatments when P fractions are being used as tools for nutritional diagnostics.
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