Induction of Glutamine Synthetase Activity in Nonnodulated Roots of Glycine max, Phaseolus vulgaris, and Pisum sativum.

Nitrate or ammonium fertilization significantly increased glutamine synthetase (GS) activity in nonnodulated roots of French bean (Phaseolus vulgaris), soybean (Glycine max), and pea (Pisum sativum). Western analysis revealed substantial GS antibody-positive protein in root extracts that had minimal GS activity, indicating that an inactive form of GS may be present in nonfertilized plants.