Document: OWE-3-30-10

Does the temperature sensitive of plant respiration vary among contrasting species and environmental conditions?

ATKIN, O.K.* ¹, B.R.BYRNE ¹, E.COVEY-CRUMP ¹ and I.SCHEURWATER ^1,2

University of York, York, North Yorkshire YO10 5AQ United Kingdom ¹
Utrecht University, Utrecht, 3584 CA The Netherlands ²

Abstract:
The response of plant respiration to future changes in temperature will be critical in determining the response of vegetation to global environmental change. Respiration is often temperature sensitive, with the temperature sensitivity often being quantified by the Q₁₀ (the rate at temperature T +10^oC/rate at temperature T). Although the factors responsible for variations in Q₁₀ have not been elucidated, changes in the demand for respiratory products, particularly ATP are likely to play a role. We have investigated the extent to which the Q₁₀ of respiration varies among twenty contrasting herbaceous and woody plant species that differ in maximum potential growth rate and thus demand for ATP. Our work has also investigated the impact of the environment (e.g. irradiance, growth temperature) on the Q₁₀ of respiration. Several potentially fast and slow-growing species were grown under controlled-environment conditions. Leaf respiration rates were measured as CO₂ efflux, while root respiration rates were determined using an O₂ electrode. Our results indicate that there is little interspecific variation in the Q₁₀ of respiration, when the Q₁₀ is calculated over a broad temperature range. In all species, Q₁₀ values are reduced in stressed plants (i.e. plants grown at very high temperatures) compared to plants grown under more favourable conditions. The temperature sensitivity of respiration also decreases as measurement temperature is increased. Moreover, the Q₁₀ of leaf respiration is dramatically reduced in illuminated leaves compared to leaves in darkness. This has important implications for net photosynthesis and the carbon budget of plants. We conclude that the Q₁₀ of a small number of plant species may be useful in predicting the temperature response of other species grown under identical conditions. However, the fact that Q₁₀ values are suppressed in the light and are reduced in stressed plants/high measurement temperatures demonstrates that it is not possible to extend lab-based measurements to plants growing under natural conditions.

Keywords: respiration, temperature, leaves, roots, carbon balance

This abstract is being presented at: 11:00 AM in session:
Oral Session #1: Plant Carbon Allocation.