EFFECT OF MG, ZN AND MO SALTS ON NITRATE REDUCTASE-ACTIVITY AND SOLUBLE-PROTEIN CONTENT IN LEAVES OF QUERCUS-SERRATA

Leaves of Quercus serrata seedlings were sprayed with solutions of dif ferent concentrations of Mg, Zn and Mo-salts and activity of nitrate r eductase (NRA) and soluble protein contents were determined in fresh l eaves of different ages. The optimum dose for magnesium sulphate and z inc sulphate was 2.5 mM while for ammonium molybdate it was 0.01 mM. U nder optimum doses of these nutrients high levels of NRA and protein c ontents were maintained upto 28 d of spray. Observations on NRA were f urther confirmed by leaf direct treatment and excised shoot-dipping ex periments which showed maximum NRA at comparatively much lower concent rations of ions than those used for spray.