Thermal acclimation of plant respiration is tissue type specific

Carbon released from the land surface is one of the largest fluxes of carbon dioxide (CO₂) between the atmosphere and the Earth’s surface, with plant respiration accounting for about half of this flux. As a result, terrestrial biosphere models are highly sensitive to changes in plant respiratory processes. The thermal acclimation response of plant respiration is one such process yet is often not included in these models due to poor understanding of the response. Thermal acclimation of respiration is defined as a change in the instantaneous response of respiration to temperature as a result of a longer-term change in temperature. This effect can result in a dampened respiratory response to temperature and reduce the future rate of atmospheric CO₂ rise. Whilst all living plant tissue respires, few studies have looked at the differences in thermal acclimation across plant tissues.

In a recent study published in AoBP, Smith et al. aimed to better understand the thermal acclimation response of leaves, stems and roots of eight disparate plant species. They found that temperature acclimation of respiration does indeed differ by tissue type. Tissue that does not photosynthesize was found to have more homeostatic responses to temperature (i.e. more stable) than photosynthetic tissue. This was found due to the strong link between photosynthetic biochemistry and respiration fluxes. These results suggest that plant respiratory responses to changing temperatures, such as future warming, will be tissue type-specific. The link to photosynthesis found in this study provides an avenue for improving the representation of these respiratory responses in large-scale carbon cycle models. The authors are also hopeful that the data from their study will be used to develop and test better mechanistic models of dark respiration and have made their dataset publicly available for such a purpose.

Researcher highlight

Nick Smith grew up in Indiana, USA, where he developed an interest in environmental studies and Ecology in particular. He decided to use these interests to help society better prepare for and combat global change. He pursued a PhD in plant-climate interactions with Jeff Dukes at Purdue University. This work was extended to larger scales during a postdoc at Lawrence Berkeley National Lab with Trevor Keenan.

Nick now teaches and runs his own lab at Texas Tech University, where he is dedicated to mentoring the next generation of scientists. His group explores biosphere-atmosphere feedbacks, broadly defined. Recently, Nick has become interested in developing plant ecophysiological theory as a means to explore mechanisms ecological processes at the community and ecosystem scales. He will use his work to provide more reliable projections of future global change, leading to more informed policy decisions.