Abstract - With the onset of climate change we have seen ongoing increases in mean global temperature, including a rise in night temperatures that has outpaced the rate of daytime warming. Declines in wheat yield associated with high temperature have been linked to decreases in the efficiency of both photosynthesis and respiration – processes that ultimately determine plant biomass accumulation and yield. While the response of wheat photosynthesis to warming has been fairly well described in the literature, there has been comparatively less attention paid to the high temperature response of wheat respiration, and even less focus on the influence of night warming on both processes. This seminar will detail a combination of field and controlled environment studies used to investigate the response of wheat respiration to warming. There will be a particular focus on the effects of night warming, including potential discrepancies in the response of respiratory O₂ consumption versus respiratory CO₂ release, as well as changes in the capacity of the alternative mitochondrial electron transport pathway under warm nights. The influence of night warming on photosynthesis will also be briefly discussed; namely, an examination of the upregulation of the heat tolerant isoform of Rubisco activase under heatwave conditions, and the apparent priming effect that night warming has on this response.

Biography - After completing a double degree (BArts/BSc) at the ANU in 2016, Brad went on to do an Honours project in Owen Atkin’s lab working on wheat photosynthetic heat tolerance in 2017. Following this, Brad began his PhD project in the Atkin lab in January 2018, joining a GRDC-funded project on improving heat tolerance in wheat through more efficient carbon allocation. His work has revolved around understanding the effects of high temperature on wheat respiration, with a particular focus on the influence of night time warming. Following the conclusion of his PhD, Brad will be taking up a post-doc position in Nick Smith’s lab at Texas Tech University.