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United States Department of Agriculture

Agricultural Research Service

Title: Elevated atmospheric carbon dioxide and ozone concentrations alter LAI through changes in phenology and leaf growth

item Mcgrath, Justin
item Ainsworth, Elizabeth - Lisa

Submitted to: Plant Biology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 5/15/2008
Publication Date: 6/23/2008
Citation: McGrath, J.M., Ainsworth, E.A. 2008. Elevated atmospheric carbon dioxide and ozone concentrations alter LAI through changes in phenology and leaf growth. American Society of Plant Biologists Annual Meeting. Paper No. P04003. Available:

Interpretive Summary:

Technical Abstract: Leaves are critical for harvesting light energy, taking up carbon dioxide (CO2) and transpiring water for cooling. Changes in leaf growth, expansion or development can integrate across the plant canopy and growing season to significantly impact productivity, yield and plant-atmosphere fluxes. Although the effects of elevated CO2 concentration ([CO2]) and ozone concentration ([O3]) on leaf expansion have been studied individually, few studies examine leaf expansion in more realistic simulations of future conditions, with simultaneously elevated CO2 and O3. Furthermore, previous research has predominantly been done in controlled environments or open-top chambers, which alter the soil-plant-atmosphere continuum and may alter natural patterns of leaf growth. The purpose of this study is to examine leaf growth and expansion in plants exposed to elevated [CO2] and elevated [O3] in a field setting to determine how growth parameters such as final leaf area, leaf number, and growth rate are altered by climate change. It was found that elevated [CO2] and elevated [O3] increased and decreased leaf area index (LAI), respectively, while the combination treatment increased LAI. Changes in LAI were caused by changes in both the number of leaves per plant and the individual leaf area. Changes in leaf area were primarily caused by larger and smaller leaf starting sizes in elevated [CO2] and elevated [O3], respectively. Changes in leaf area were related to cell size and number, where leaves in elevated [CO2] had more cells and leaves in elevated [O3] had smaller cells. Future research is investigating the molecular basis for these changes in cell size at elevated [CO2] and elevated [O3].

Last Modified: 06/26/2017
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