Document Detail

Nitrogen storage and remobilization by trees: ecophysiological relevance in a changing world.
MedLine Citation:
PMID:  20551251     Owner:  NLM     Status:  MEDLINE    
The role of carbon (C) and nitrogen (N) storage by trees will be discussed in terms of uncoupling their growth from resource acquisition. There are profound differences between the physiology of C and N storage. C storage acts as a short-term, temporary buffer when photosynthesis cannot meet current sink demand and remobilization is sink driven. However, the majority of C allocated to non-structural carbohydrates such as starch is not reused so is in fact sequestered, not stored. In contrast, N storage is seasonally programmed, closely linked to tree phenology and operates at temporal scales of months to years, with remobilization being source driven. We examine the ecological significance of N storage and remobilization in terms of regulating plant N use efficiency, allowing trees to uncouple seasonal growth from N uptake by roots and allowing recovery from disturbances such as browsing damage. We also briefly consider the importance of N storage and remobilization in regulating how trees will likely respond to rising atmospheric carbon dioxide concentrations. Most studies of N storage and remobilization have been restricted to small trees growing in a controlled environment where (15)N can be used easily as a tracer for mineral N. We highlight the need to describe and quantify these processes for adult trees in situ where most root N uptake occurs via ectomycorrhizal partners, an approach that now appears feasible for deciduous trees through quantification of the flux of remobilized N in their xylem. This opens new possibilities for studying interactions between N and C allocation in trees and associated mycorrhizal partners, which are likely to be crucial in regulating the response of trees to many aspects of global environmental change.
Peter Millard; Gwen-Aelle Grelet
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Review     Date:  2010-06-15
Journal Detail:
Title:  Tree physiology     Volume:  30     ISSN:  0829-318X     ISO Abbreviation:  Tree Physiol.     Publication Date:  2010 Sep 
Date Detail:
Created Date:  2010-08-10     Completed Date:  2010-11-05     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100955338     Medline TA:  Tree Physiol     Country:  Canada    
Other Details:
Languages:  eng     Pagination:  1083-95     Citation Subset:  IM    
Macaulay Land Use Research Institute, Craigiebuckler, Aberdeen, UK.
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MeSH Terms
Adaptation, Physiological
Carbon / metabolism
Nitrogen / metabolism*
Trees / physiology*
Reg. No./Substance:
7440-44-0/Carbon; 7727-37-9/Nitrogen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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