Plant and Soil

, Volume 233, Issue 2, pp 283–290

Influence of a pulsed nitrogen supply on growth and nitrogen uptake in alpine graminoids

  • William D. Bowman
  • Carol J. Bilbrough
Article

DOI: 10.1023/A:1010571920890

Cite this article as:
Bowman, W.D. & Bilbrough, C.J. Plant and Soil (2001) 233: 283. doi:10.1023/A:1010571920890
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Abstract

The supply of N in alpine soils is influenced by environmental factors (freeze-thaw, drying-rewetting, release of N from winter snowpack) which lead to a pulsed nature in plant N availability. To address the ability of alpine species to acquire N and grow when N is supplied in a pulsed manner, six alpine graminoid species, 3 sedges (Cyperaceae) and 3 grasses (Poaceae), were grown under 3 treatments: low and high N supply applied 3 times weekly, and a pulsed N supply applied once weekly at the same concentration as the high N treatment, but with the same total N supply as the low N treatment. Growth, biomass allocation, and N uptake were the same in all species for plants grown under a pulsed N treatment relative to a constant N supply with the same amount of total N. Root:shoot ratios and uptake of experimentally applied 15N indicated there were no adjustments in growth allocation or root uptake capacity in the plants to enhance the uptake of N when supplied in a pulsed relative to a more constant supply. The fertility of the site from which the graminoids were collected did not influence the plants' ability to respond to a high versus a low N supply, but instead growth form was more important. Grasses exhibited variation in growth, biomass allocation, and N uptake in response to changes in N supply, while sedges did not.

alpine graminoids growth allocation plasticity in growth response 

Copyright information

© Kluwer Academic Publishers 2001

Authors and Affiliations

  • William D. Bowman
    • 1
  • Carol J. Bilbrough
    • 2
  1. 1.Mountain Research Station, Institute of Arctic and Alpine Research and Department of Environmental, Population, and Organismic BiologyUniversity of ColoradoBoulderUSA
  2. 2.Department of Renewable ResourcesUniversity of WyomingLaramieUSA

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