Nitrogen Distribution in Roots and Tops of Winter Wheat1
- T. L. Smith,
- G. A. Peterson and
- D. H. Sander2
The hypothesis has been proposed that the observed N losses from the aboveground parts of wheat (Triticum aestivum L.) near maturity might be explained by N redistribution to roots during the late grainfill period. This experiment was designed to test this hypothesis. Plant response to four N levels using a modified Hoagland's solution was studied in gravel culture. Roots and tops were harvested 12 times during the growth cycle and analyzed for N content. Nitrogen uptake patterns for roots and shoots were similar. At about 50 days after jointing (Feeke's Stage = 11.2) both roots and shoots began to lose N, while head N increased from anthesis to maturity. Gains in head N exceeded the amounts lost from the roots and shoots. So, N uptake from the culture solution continued through maturity. The hypothesis that N is redistributed to the roots near maturity in winter wheat was rejected. Roots were actually a source of N for translocation to the grain, as were aboveground stems and leaves.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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