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This article in CS

  1. Vol. 49 No. 3, p. 1040-1048
    Received: May 30, 2008

    * Corresponding author(s): mab@agr.gc.ca
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Response of Nitrogen Uptake and Partitioning to Critical Nitrogen Supply in Oat Cultivars

  1. G. Q. Zhaoab,
  2. B. L. Ma *a and
  3. C. Z. Renac
  1. a Eastern Cereal and Oilseed Research Centre (ECORC), Agriculture and Agri-Food Canada, Central Experimental Farm, 960 Carling Ave., Ottawa, ON, Canada, K1A, 0C6
    b permanent address: College of Grassland Science, Gansu Agricultural Univ., Lanzhou, 730070, Gansu Province, China
    c permanent address: Baicheng Academy of Agricultural Science, Baicheng, 137000, Jilin Province, China


Nitrogen uptake and partitioning in oat (Avena sativa L.) are not well documented. A greenhouse study was conducted to determine the critical timing of N supply on the growth, N uptake, and partitioning. Plants grown in plastic pots were subjected to five N fertilization regimes: (i) control, N supply from seedling to physiological maturity (PM); (ii) N supply from seedling to flag leaf; (iii) N supply from flag leaf to PM; (iv) N supply from seedling to heading; and (v) N supply from heading to PM. Leaf chlorophyll content, plant dry matter (DM), and N uptake and accumulation were measured. Total plant DM was 21% greater for naked ‘VAO-2’ than for covered ‘Prescott’, while both genotypes produced similar grain yields. Varietal differences in total plant N were significant (P < 0.05) with average of 18% higher N content for VAO-2, but most of its accumulated N was in the vegetative components. For both varieties, N supply was more critical before heading than thereafter. Compared with the control, restriction of N supply from seedling to flag leaf stage significantly reduced spikelet number (28%) and grain yield (26%). Withholding N supply until heading reduced yield by up to 65% and N uptake by 75%. No yield reduction occurred when N was withheld from flag leaf or heading to PM. Although naked VAO-2 accumulated more N than Prescott under the same conditions, partitioning of N to the grain in VAO-2 was less efficient.

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