title: Dry matter and nitrogen accumulation are not affected by superoptimal concentration of ammonium in flowing solution culture with pH control.
abstract: While it is known that superoptimal concentrations of the nitrate (NO3-) ion in solution culture do not increase NO3- uptake or dry matter accumulation, the same is not known for the ammonium (NH4+) ion.  An experiment was conducted utilizing flowing solution culture with pH control to investigate the influence of superoptimal NH4+ concentrations on dry matter, nitrogen (N), potassium (K), calcium (Ca), and magnesium (Mg) accumulation by nonnodulated soybean plants.  Increasing the NH4+ concentration in solution from 1 to 10 mM did not affect dry matter or N accumulation.  Accumulations of K, Ca, and Mg were slightly decreased with increased NH4+ concentration.  The NH4+ uptake system, which is saturated at less than 1mM NH4+, is able to regulate uptake of NH4+ at concentrations as high as 10 mM.
authors.affiliation: Department of Agronomy and Soils, Clemson University, Florence, SC 29501-9603, USA.
authors.forename: J W
authors.initials: JW
authors.lastname: Rideout
authors.forename: C D
authors.initials: CD
authors.lastname: Raper
mesh_terms: D001692:Biological Transport; D018533:Biomass; D002118:Calcium / Q000378:metabolism; D005308:Fertilizers; D006863:Hydrogen-Ion Concentration; D018527:Hydroponics / Q000379:methods; D008274:Magnesium / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000493:pharmacokinetics* / Q000494:pharmacology*; D013025:Glycine max / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*
chemical_list: D005308:Fertilizers; D000644:Quaternary Ammonium Compounds; D008274:Magnesium; D009584:Nitrogen; D011188:Potassium; D002118:Calcium