Journal Article

Why do genotypes of <i>Picea glauca</i> differ in their growth response to elevated CO<sub>2</sub>?

Junyan Zhang, Erin E. Mycroft, Greg Adams and Ed Reekie

Edited by David Tissue

in Tree Physiology

Volume 31, issue 1, pages 16-21
Published in print January 2011 | ISSN: 0829-318X
Published online January 2011 | e-ISSN: 1758-4469 | DOI: http://dx.doi.org/10.1093/treephys/tpq097
Why do genotypes of Picea glauca differ in their growth response to elevated CO2?

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Meta-analyses reveal that fast-growing species have a greater growth response to elevated CO2 than slow-growing species. It is unknown whether this is a direct response or whether inter-specific differences in growth are simply correlated with other physiological or morphological differences among species that affect the growth response to CO2. Here we use intra-specific variation in Picea glauca to examine the mechanistic basis for this relationship. Relative growth rate (RGR) of 29 genotypes grown at ambient (370 µl l−1) or elevated (740 µl l−1) CO2 was measured. Physiological and morphological traits describing differences in allocation, canopy structure, stomatal function and photosynthesis were determined. Most variation in RGR (74%) was explained by traits associated with canopy structure. Although there was a strong correlation between RGR740 and RGR370, we found no evidence that genotypes that grew fast at ambient CO2 had a greater relative growth response to CO2. Given that the pattern found at the intra-specific level differed from that reported at the inter-specific level, our results suggest that RGR per se does not affect the growth response to CO2. Rather, the CO2 growth response is determined by traits that may or may not be correlated with RGR.

Keywords: allocation patterns; canopy structure; carbon isotope ratio; genetic variation; global change; relative growth rate

Journal Article.  3923 words.  Illustrated.

Subjects: Plant Sciences and Forestry

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