Glutamine synthetase activity, ammonium accumulation and growth of callus cultures of Asparagus officinalis L. exposed to high ammonium or phosphinothricin

amino acids ammonia ammoniac ammonium ammonium compounds ammoniumverbindung asparagus officinalis cal callo callus compuestos de amonio crecimiento croissance cultivo de tejidos culture de tissu glutamate ammonia ligase glutamina sintetasa glutamine synthetase growth kalluskultur organophosphorus compounds pflanzenphysiologie phosphin tissue culture