|Mcgrath, Justin - UNIVERSITY OF ILLINOIS|
Submitted to: Plant Biology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: March 20, 2009
Publication Date: July 18, 2009
Citation: McGrath, J.M., Ainsworth, E.A. 2009. Increased Cell-Wall Extensibility in Elevated CO2 and O3 Indicates Modification of Leaf Cell-Wall Structure [abstract]. Plant Biology Annual Meeting. Plant Biology 2009, July 18-22, 2009, Honolulu, HI. Technical Abstract: Soybean leaf size is increased by growth in elevated [CO2] and decreased in elevated [O3]. The mechanism likely involves changes in cell biophysical properties. Cell growth rate is a function of cell-wall extensibility, a measure of how easily the wall expands in response to turgor. Modification of cell-wall structure through cleavage of cellulose cross links or change in chemical composition can modify extensibility, factors which may change with growth in elevated [CO2] or [O3]. However, extensibility has not been examined in response to elevated [CO2] and [O3] in combination in a field setting. Free-Air Concentration Enrichment (FACE) experiments are able to elevate gas concentration in the field with minimal disturbance to the microclimate. We measured stress-strain curves of FACE-grown soybean leaf tissue from growing and mature leaves to determine if elevated [CO2] and [O3] affect cell-wall extensibility. Elevated [CO2] and [O3] singly and in combination increased cell-wall extensibility of leaf tips on average by 11%. Extensibility at the base of the leaf was unchanged, indicating a possible spatial difference in growth rates, a characteristic not usually seen in soybean leaves. These data implicate possible changes in cell-wall structure and correlate with other studies that show an increase in the activity and expression of cell-wall loosening enzymes in elevated [CO2] and [O3].