Effects of salinity stress on the activity of glutamine synthetase and glutamate dehydrogenase in triticale seedlings

The effect of salinity on the activity of glutamine synthetase (GS EC 6.3.1.2.) and glutamate dehydrogenase (NAD(P)H-GDH EC 1.4.1.2-4) in shoots and roots of triticale seedlings was investigated. Stressed plants were cultured hydroponically on the 100 mM NaCl-enriched medium for 7 days and the physiological responses were measured. Apart from changes in morphology of plants, alterations in GS and NAD(P)H-GDH activity were reported. GS activity in roots of stressed plants grew slightly and in shoots it decreased by approx. 30% as compared to control plants. In shoots of both control and stressed plants two GS isoforms were detected: cytoplasmic (GS1) and chloroplastic (GS2). A drop in total GS activity in shoots of NaCl-treated plants was due to the drop in activity of GS2 isoform. The activity of GS1 grew slightly under saline stress. After staining of gels for GDH activity, no changes in isoforms were noted as compared with the control plants.