|SIEBERS, MATTHEW - University Of Illinois|
|DRAG, DAVID - University Of Illinois|
|LOCKE, ANNA - University Of Illinois|
|RIOS ACOSTA, L - University Of Illinois|
|LEAKEY, A D B - University Of Illinois|
|Ainsworth, Elizabeth - Lisa|
Submitted to: Global Change Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/5/2015
Publication Date: 7/21/2015
Citation: Siebers, M.H., Yendrek, C.R., Drag, D., Locke, A.M., Rios Acosta, L., Leakey, A., Ainsworth, E.A., Bernacchi, C.J., Ort, D.R. 2015. Heat waves imposed during early pod development in soybean (Glycine max) cause significant yield loss despite a rapid recovery from oxidative stress. Global Change Biology. 8(21):3114-3125.
Interpretive Summary: Agricultural production faces a future of multi-faceted challenges from global climate change. Continued emissions of greenhouse gases will increase mean annual temperatures by 2.5 to 4.3°C in important crop growing regions of the world by 2080-2099, according to the Intergovernmental Panel on Climate Change A1B scenario. The emission of greenhouse gases into the atmosphere has been accelerating since the beginning of industrial revolution ~150 years ago. Since the year 2000, carbon dioxide and other forcing gases have been accumulating in the atmosphere at unprecedented rates exceeding even the most aggressive A1FI emission scenario and portend global warming at the higher end of the predicted range. In conjunction with the changes in the mean global temperature, extreme heat events or heat waves are predicted to increase in frequency, length and intensity over most land areas. These predictions, all of which foretell a warmer future, suggest that there is a need to understand how important agronomic species will fare during regionally defined extreme heat events. To investigate the impact that extreme heat events will have on soybean in the future we imposed heat waves by raising the temperature of soybean canopies by 6°C for three day periods spanning different crop developmental stages to determine the effects of a historically plausible heat wave in central Illinois on soybean physiology and productivity.
Technical Abstract: This study is the first field based experiment that uses IR heaters to study the effects of a regionally defined heat wave on soybean physiology and productivity. The heating technology was successful and all of the heat waves were maintained at the target temperature for the three day duration of the treatment. Midday levels of A, gs and carbon metabolism were immediately reduced by the heat wave treatments but followed by a quick recovery within 24 h of the end of the heat wave. Similarly, 'PSII, oxidative stress and SLW in the heat wave treatments were the same as the control the day after the heat wave. Vcmax was increased during Wv11.1 but both Vcmax and Jmax decreased during Wv11.2. Heat waves did not alter the rate of reproductive or vegetative development but, there were significant reductions in yield when heat waves over lapped reproductive stages. There was no evidence of yield compensation by soybean following the heat waves.