Dynamics of leaf expansion and development in response to climate change
Leaves are the primary assimilatory surface of plants and as such are involved in processes which range on many scales from exchange of individual CO2 and water molecules all the way to global biogeochemical cycling. Leaf expansion in elevated CO2 and O3 are being examined in soybean and aspen. Elevated CO2 increases leaf area index (LAI), in part due to larger leaves and in part to changes in phenology. Elevated O3 decreases LAI, in part due to decreased individual leaf area. Current work is focusing on the biophysical and molecular underpinnings of these responses.
Meta-analysis of photosynthetic carbon uptake in response to elevated atmospheric CO2 and O3
Literally thousands of individual studies of crop responses to elevated [CO2] or elevated [O3], either singly or in combination, provide a rich database from which to extract estimates of the mean responses of major food crops to these important global changes. Over the past 4 decades, the methods for fumigating plants with [CO2] and [O3] have changed, the cultivars of major crops have changed, and the background (ambient) concentrations of [CO2] and [O3] have changed. These factors pose challenges to calculating a mean response. However, meta-analysis provides a tool for drawing quantitative conclusions from diverse data sources and experiments. Our research summarizes the response of the major grain and oilseed crops, namely maize (Zea mays), rice (Oryza sativa), wheat (Triticum aestivum) and soybean (Glycine max), to rising atmospheric [CO2] and [O3] concentrations using meta-analysis. Understanding the mean response of crops to rising [CO2] and [O3] is a first step towards developing adaptation strategies for the future.
Integrated analysis of plant molecular and biochemical responses to global atmospheric change
One of the important mechanisms by which plants respond to environmental change is the oxidative stress response. Damage caused at the cellular level by oxidative stress feeds forward to decrease leaf photosynthesis and canopy and ecosystem productivity. The antioxidant system consists of enzyme cycles and metabolite pools that maintain a balanced redox state. Changes in one component may or may not affect the redox balance depending on the condition and activity of the other metabolites and enzymes; therefore integration of the biochemical results with changes in antioxidant transcripts and enzymes will provide a mechanistic analysis of the response of the plant antioxidant system to global change.
Variation in soybean cultivar responses to elevated ozone
Ground level ozone is currently reducing soybean yields by ~10 to 15%. This
environmental stress may be causing greater yield loss state-wide than any single
soybean disease, and it is projected to continue to get worse. We aim to identify new and rapid physiological and molecular screens for ozone
tolerance. These tools could eventually be used to screen a wider subset of the USDA soybean germplasm collection.