The Effect of Elevated Carbon Dioxide and Ozone on Soybean Development, Leaf Anatomy and Productivity

Leaf area is significantly reduced in elevated [O3]; however, it is significantly increased in elevated [CO2]. This increase in leaf area, along with the increased number of main stem nodes, result in the previously reported increase in leaf area index observed in soybeans grown in elevated [CO2]. This increased photosynthetic tissue, along with increases in light-saturated photosynthesis observed under elevated atmospheric [CO21 is expected to result in a proportional increase in canopy photosynthesis or gross primary production (GPP). A draw-back of FACE is that GPP cannot be measured directly. Measurements of micrometeorology, leaf photosynthetic properties and canopy structure were combined in an adapted version of the Integrated Scientific Assessment Model (ISAM) to estimate GPP. The results of this model showed an increase in diurnal GPP, which resulted in a season-long 30% stimulation of both GPP and net primary production (NPP). Although the NPP modeled in this way agreed closely in absolute terms with that estimated from biomass measurements, the stimulation in NPP due to elevated [CO 2] was very much higher than the biomass measurements showed. The potential causes of this discrepancy are discussed and indicate new questions to be addressed.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Biology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Castro, Joseph Carlos

Contributors dc:contributor

• Long, Stephen P.

• Biology, Plant Physiology

Language dc:language

eng

Identifier

(MiAaPQ)AAI3411447

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/85386