Ammonium Effects on Nutrient Cation Absorption by Wheat1
- W. J. Cox and
- H. M. Reisenauer2
Additions of small amounts of NH1 to adequate-NO3 culture have been shown to increase crop yield and total N content, and to decrease the plant's content of metal cations. The magnitudes of these effects can be appreciable. Accordingly, experiments were done to elucidate their mechanisms, and to evaluate their roles in crop production. Wheat (Triticum aestivum L. ‘INIA’) was grown in the greenhouse in dilute constant-composition cultures that supplied, in factorial combination, three levels of NH4 with four levels of either K, Ca, Mg, Mn, or Zn. Intake of mineral cations increased with the concentration of the ion in solution and was decreased by added NH4. Ammonium had a greater effect on the intake of the divalent than of the monovalent cations. Among the divalent cations the magnitude of the NH4 effect varied in the order: Zn > Mn ≥ Mg > Ca. The reduced influx of multivalent cations from added NH4 is postulated to result from the NH4 induced reduction of the level of slowly diffusible organic anions within the root. This results in a smaller chelate sink, increased internal cation activity, and reduced net influx.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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