Research Review: Response of Root Respiration to Changes in Temperature and Its Relevance to Global Warming

• Published in: The New phytologist 2000-07, Vol.147 (1), p.141-154
• Main Authors: Atkin, Owen K., Edwards, Everard J., Loveys, Beth R.
• Format: Article
• Language: English
• Subjects: Acclimatization; Carbon dioxide; Low temperature; Plant roots; Plants; Respiration; Root growth; Soil respiration; Soil temperature; Soil temperature regimes
• ISSN: 0028-646X; 1469-8137

Global warming over the next century is likely to be associated with a change in the extent to which atmospheric and soil temperatures fluctuate, on both a daily and a seasonal basis. The average annual temperature of the Earth's surface is expected to increase, as is the frequency of hot days. In this review, we explore what effects short-term and long-term changes in temperature are likely to have on root respiratory metabolism, and what impacts such changes will have on daily, seasonal and annual CO2release by roots under field conditions. We demonstrate that Q10values, and the degree of acclimation, differ between and within plant species. Changes in the temperature sensitivity of respiration with measuring temperature are highlighted. Temperature-dependent changes in adenylate control and substrate supply are likely to control the Q10and degree of acclimation of root respiration. Limitations in respiration capacity are unlikely to control respiratory flux at most temperatures. The potential role of nonphosphorylating pathways such as the alternative oxidase in controlling Q10values is highlighted. The possibility that potentially rapid changes in adenylate control might underlie the acclimation response (rather than slow changes in enzyme capacity) has implications for the total amount of CO2respired by roots daily and annually. Our modelling suggests that rapid acclimation will result in near-perfect homeostasis of respiration rates and minimize annual CO2release. However, annual CO2release increases substantially if the speed of full acclimation is lower. Our modelling exercise also shows that high Q10values have the potential to increase daily and annual CO2release substantially, particularly if the frequency of hot days increases after global warming.