HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Wilhelm, W. W. Articles by Harrell, D. M. Search for Related Content PubMed Articles by Wilhelm, W. W. Articles by Harrell, D. M. Agricola Articles by Wilhelm, W. W. Articles by Harrell, D. M. Related Collections Crop Growth and Development Wheat Plant Analysis Plant Nutrition Nitrogen

WHEAT

Nitrogen and Dry Matter Distribution by Culm and Leaf Position at Two Stages of Vegetative Growth in Winter Wheat

^a USDA-ARS, Soil and Water Conservation Res. Unit, Univ. of Nebraska, Lincoln, NE 68583
^b USDA-ARS, Great Plains Systems Res. Unit, P.O. Box E, Fort Collins, CO 80522
^c School of Natural Resource Sci., Univ. of Nebraska, Lincoln, NE 68583 (formerly, USDA-ARS, Soil and Water Conservation Res. Unit, Univ. of Nebraska, Lincoln, NE 68583)

* Corresponding author (wwilhelm1{at}unl.edu)

Received for publication September 25, 2001. Knowledge of N and assimilate partitioning in wheat (Triticum aestivum L.) improves management efficacy and crop model development. Our purpose was to describe N and dry matter distribution during vegetative growth of blades, sheaths, and internodes on four culms. Winter wheat grown at the Colorado State University Horticultural Farm was sampled at Haun Stage 5 and jointing. Samples were dried, weighed, and analyzed for N. As the canopy developed and older tissue contributed more of total tissue, N concentration decreased although N mass and dry weight increased. Dry matter and N mass decreased from MC to T1 and T2 to T11, while the reverse order was found for N concentration. Dry weight and N mass decreased as culm order increased (culm age decreased), because phytomers were smaller and fewer existed. Nitrogen concentration had the opposite trend because new tissue contained about 40 g N kg^-1 but declined as the tissue aged to 30 g N kg^-1. Initial growth of all tissues had concentrations >50 g N kg^-1 and at senescence declined to 19 g N kg^-1. Phytomer positions on different culms tended to have similar N concentrations while identical phytomers on primary tillers tended to have greater dry weights than those on the MC and secondary tillers. Phytomers tended to increase in N concentration and mass and dry weight acropetally. Results show that viewing the canopy as the interplay of appearance, growth, interaction, and senescence of culms or phytomers can increase understanding of canopy N and dry weight dynamics.

Abbreviations: GDD, growing degree-days • MC, main culm • SE, standard error of the mean • T1, primary tiller arising from the axillary bud of the first leaf on the MC • T2, primary tiller arising from the axillary bud of the second leaf on the MC • T11, secondary tiller arising from the axillary bud of first leaf on primary tiller T1