Skip to page content
USDA Forest Service
  
Treesearch

Research & Development Treesearch

 
Treesearch Home
About Treesearch
Contact Us
Research & Development
Forest Products Lab
International Institute of Tropical Forestry
Northern
Pacific Northwest
Pacific Southwest
Rocky Mountain
Southern Research Station
Help
 

Science.gov - We Participate


USA.gov  Government Made Easy


Global Forest Information Service

US Forest Service
P.O. Box 96090
Washington, D.C.
20090-6090

(202) 205-8333

You are here: Home / Search / Publication Information
Bookmark and Share

Publication Information

View PDF (231 KB)

Title: Effects of above- and below-ground competition from shrubs on photosynthesis, transpiration and growth in Quercus robur L

Author: Jensen, Anna M.; Lof, Magnus; Gardiner, Emile S.;

Date: 2011

Source: Environmental and Experimental Botany 71:367-375

Publication Series: Scientific Journal (JRNL)

Description: For a tree seedling to successfully establish in dense shrubbery, it must maintain function under heterogeneous resource availability. We evaluated leaf-level acclimation in photosynthetic capacity, seedling-level transpiration, and seedling morphology and growth to gain an understanding of the effects of above- and below-ground competition on Quercus robur seedlings. Experimental seedlings were established in a typical southern Swedish shrub community where they received 1 of 4 competition levels (above-ground, below-ground, above- and below-ground, or no competition), and leaf-level responses were examined between two growth flushes. Two years after establishment, first-flush leaves from seedlings receiving above-ground competition showed a maximum rate of photosynthesis (Amax) 40% lower than those of control seedlings. With the development of a second flush above the shrub canopy, Amax of these seedlings increased to levels equivalent to those of seedlings free of light competition. Shrubby competition reduced oak seedling transpiration such that seedlings exposed to aboveand below-ground competition showed rates 43% lower than seedlings that were not exposed to competition. The impaired physiological function of oak seedlings growing amid competition ultimately led to a 60–74% reduction in leaf area, 29–36% reduction in basal diameter, and a 38–78% reduction in total biomass accumulation, but root to shoot ratio was not affected. Our findings also indicate that above ground competition reduced Amax, transpiration and biomass accumulation more so than below-ground competition. Nevertheless, oak seedlings exhibited the ability to develop subsequent growth flushes with leaves that had an Amax acclimated to utilize increased light availability. Our findings highlight the importance of flush-level acclimation under conditions of heterogeneous resource availability, and the capacity of oak seedlings to initiate a positive response to moderate competition in a shrub community.

Keywords: Pedunculate oak, Neighboring effect, Vertical light gradient, Light acclimation, hotosynthetic capacity

Publication Notes:

  • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
  • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.

XML: View XML

Citation:


Jensen, Anna M.; Lof, Magnus; Gardiner, Emile S. 2011. Effects of above- and below-ground competition from shrubs on photosynthesis, transpiration and growth in Quercus robur L. seedlings. Environmental and Experimental Botany 71:367-375.

 


 [ Get Acrobat ]  Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility

USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.