GLUTAMATE-DEHYDROGENASE AND GLUTAMINE-SYNTHETASE ACTIVITIES IN MAIZE UNDER WATER AND SALT STRESS

NADH-GDH activity from roots of maize plants subjected to polyethylene glycol (PEG) and salt stress decreased rapidly after 12 h of treatment . GS activity did not diminish so markedly. In the first leaves, GS ac tivity was surprisingly high when plants were subjected to both types of stress for 6 h. There were clear differences in the isoenzymatic pa tterns of GDH in extracts from stressed and control plants. The respon se of GDH activity to a secondary in vitro stress, induced by adding P EG to the extracts, was different in plants under water or salt stress .