Differential effect of amino acids on nitrate uptake by intact maize roots
2002
Palove-Balang, P. | Mistrik, I. (Slovak Academy of Sciences, Bratislava (Slovak Republic). Institute of Botany)
The ability of individual amino acids to regulate nitrate uptake was studied in Zea mays L. seedlings. The amino acids were applied to the root media before the induction of inducible high-affinity transport system with 0.1 mM KNO3. Glutamine and glutamate were found to be the most effective inhibitors of uptake processes. Exclusion of conversion of glutamine to glutamic acid and to other amino acids by aminooxalacetic acid has proved that with high probability the glutamine is responsible for the observed nitrate uptake inhibition. Since the lag-phase in inhibitory effect of glutamine was shorter than 2 hours, we suppose the direct inhibition of glutamine on the nitrate carrier itself, rather than on the corresponding gene expression
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