Growth and nitrogen assimilation of soybeans in response to ammonium and nitrate nutrition

摘要: Plants supplied with moderate concentrations of NH4 + in solution generally grow poorly compared plants other sources nitrogen. Experiments were conducted a flowing culture system to determine whether growth restrictions could be avoided over an extended period the presence if root-zone pH strictly controlled and exposed during exponential when carbohydrate fluxes root are coordinated rate nitrogen acquisition. Vegetative soybeans (Glycine max [L.] Merrill) initially complete nutrient solutions containing NO3 - until stage then for 4 wk which was as either 1.0 mM +, 1 0 -, or 0.5 plus -. Acidity constantly maintained at 5 8 ± by automated control In separate experiments, irradiance (photosynthetic photon flux density [PPFD] 700 325 μE m-2 s-1) levels ...