Influencia del suministro de nitrógeno en la absorción de algunos minerales por el frijol (Phaseolus vulgaris L.)

Abstract

The investigation deals with the quantitative determination of ion uptake by the bean plant (Phaseolus vulgaris L.) namely, NO3-, Ca2+, Mg2+, K+ and phosphate, during the time elapsed between germination and preflowering stage, as influenced by nitrogen level in the substrate media. Plants were cultivated in nutrient solution. At the end of the experiment the different nutrient media were quantitatively analyzed. The remaining salts permitted to obtain, by substraction from the original concentration figures the nutrient absorption rate during the expiremental period. It was found that the uptake ok K+ and Ca2+ was in close correlation with nitrogen availability. Meanwhile, the absorption of Mg2+ and phosphate proved to be independent from nitrogen uptake. The figures shown on NO2- and K+ absorption emphasize a high requirement for both ionic species by the bean plant. The ionic equilibrium of the absorption rate demonstrated that the K/(Ca2+Mg2+) ratio diminishes as the availability NO2-N increases. It was found that the sinergistic effect exerted by nitrogen on the absorption of K+ and Ca2+ is stronger with the former. The cation/ anion ratio showed a negative correlation with respect to nitrogen availability.