Publication Date
1997
Description
Our hypothesis is that certain root N pools are utilized preferentially during the early shoot regrowth. Our objective was to determine the relative contribution of crown N, root N, and specific root N pools to shoot regrowth after defoliation. We used 15N to follow N into and out of crowns, roots, and specific root N pools, to regrowing shoots after defoliation. The low molecular weight N pool (amino acids, inorganic N,...) acquired 15N rapidly within 2 d of N application. Movement of 15N into the protein-N and insoluble-N pools was delayed initially, but continued until 8 d after N application. Defoliation 30 d after 15N application resulted in N transfer from roots and crowns to regrowing shoots. All root N pools lost 15N label initially after defoliation, with a more extensive decline occurring for the protein-N and low molecular weight-N pools.
Included in
Agricultural Science Commons, Agronomy and Crop Sciences Commons, Plant Biology Commons, Plant Pathology Commons, Soil Science Commons, Weed Science Commons
Root Nitrogen Cycling and Alfalfa Stress Tolerance
Our hypothesis is that certain root N pools are utilized preferentially during the early shoot regrowth. Our objective was to determine the relative contribution of crown N, root N, and specific root N pools to shoot regrowth after defoliation. We used 15N to follow N into and out of crowns, roots, and specific root N pools, to regrowing shoots after defoliation. The low molecular weight N pool (amino acids, inorganic N,...) acquired 15N rapidly within 2 d of N application. Movement of 15N into the protein-N and insoluble-N pools was delayed initially, but continued until 8 d after N application. Defoliation 30 d after 15N application resulted in N transfer from roots and crowns to regrowing shoots. All root N pools lost 15N label initially after defoliation, with a more extensive decline occurring for the protein-N and low molecular weight-N pools.
