Investigation on the Assimilation of Nitrogen by Maize Roots and the Transport of Some Major Nitrogen Compounds by Xylem Sap. III: Transport of Nitrogen Compounds by Xylem Sap

Xylem sap was collected from nitrogen-starved maize plants and investigations were made on the nitrogen transported. It appears from the results that several pools for different amino acids exist, which have different relations to the transport of nitrogen taken up. While in maize roots Glu, Glu-NH2 and Arg are transported directly from the place of their synthesis, the transported Asp and Ala predominantly derive from the pool of amino acids synthetized before application of nitrogen.

An explanation of this observation is offered.