Foliar nitrogen and changes in free amino acid composition of Solanum lycopersicum under cadmium toxicity: kinetics of 15NH4+

Glutamate metabolism and amino acid translocation were investigated in the control and cadmium stressed shoots of tomato (Solanum lycopersicum - 63/5 F1), using (15N) ammonium and (15N) glutamate tracers. Regardless of organ type, [15N] ammonium assimilation occurred via glutamine synthetase (EC 6.3.1.2), in the control and stressed plants, and it did not depend on glutamate dehydrogenase (EC 1.4.1.2). The [15N] ammonium and ammonium accumulation patterns support the role of glutamate dehydrogenase in the deamination of [15N] glutamate to provide 2-oxoglutarate and [15N] ammonium. In the prese...

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