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Are gas exchange responses to resource limitation and defoliation linked to source: sink relationships?


Pinkard, E and Eyles, A and O'Grady, AP, Are gas exchange responses to resource limitation and defoliation linked to source: sink relationships? , Plant, Cell and Environment, 34, (10) pp. 1652-1665. ISSN 0140-7791 (2011) [Refereed Article]

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Copyright 2011 Blackwell Publishing Ltd. The definitive published version is available online at:

DOI: doi:10.1111/j.1365-3040.2011.02361.x


Productivity of trees can be affected by limitations inresources such as water and nutrients, and herbivory. However, there is little understanding of their interactive effects on carbon uptake and growth.We hypothesized that: (1) in the absence of defoliation, photosynthetic rate and leaf respiration would be governed by limiting resource(s) and their impact on sink limitation; (2) photosynthetic responses to defoliation would be a consequence of changing source:sink relationships and increased availability of limiting resources; and (3) photosynthesis and leaf respiration would be adjusted in response to limiting resources and defoliation so that growth could be maintained. We tested these hypotheses by examining how leaf photosynthetic processes, respiration, carbohydrate concentrations and growth rates of Eucalyptus globulus were influenced by high or low water and nitrogen (N) availability, and/or defoliation. Photosynthesis of saplings grown with low water was primarily sink limited, whereas photosynthetic responses of saplings grown with low N were suggestive of source limitation. Defoliation resulted in source limitation. Net photosynthetic responses to defoliation were linked to the degree of resource availability, with the largest responses measured in treatments where saplings were ultimately source rather than sink limited. There was good evidence of acclimation to stress, enabling higher rates of C uptake than might otherwise have occurred.

Item Details

Item Type:Refereed Article
Research Division:Agricultural, Veterinary and Food Sciences
Research Group:Forestry sciences
Research Field:Forest health and pathology
Objective Division:Plant Production and Plant Primary Products
Objective Group:Forestry
Objective Field:Hardwood plantations
UTAS Author:Pinkard, E (Dr Elizabeth Pinkard)
UTAS Author:Eyles, A (Dr Alieta Eyles)
UTAS Author:O'Grady, AP (Dr Anthony O'Grady)
ID Code:69556
Year Published:2011
Web of Science® Times Cited:46
Deposited By:Agricultural Science
Deposited On:2011-04-29
Last Modified:2017-08-23

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