Temperature responses of photosynthesis and respiration in Populus balsamifera L.: acclimation versus adaptation

• Published in: Photosynthesis research Vol. 104; no. 1; pp. 19 - 30
• Main Authors: Silim, Salim N, Ryan, Natalie, Kubien, David S
• Format: Journal Article
• Language: English
• Published: Netherlands Dordrecht : Springer Netherlands 01.04.2010; Springer; Springer Nature B.V
• Subjects: acclimation; Acclimatization - physiology; Adaptation, Physiological - physiology; Carbon Dioxide - metabolism; Cell Respiration - physiology; Electron transport; gas exchange; Global warming; Habitats; Homeostasis; Mesophyll conductance; Photosynthesis; Photosynthesis - physiology; Physiological aspects; Phytochemistry; Plant biology; Plant Stomata - physiology; Populus - metabolism; Populus - physiology; Respiration; Ribulose-Bisphosphate Carboxylase - metabolism; Temperature; Trees
• ISSN: 0166-8595; 1573-5079
• DOI: 10.1007/s11120-010-9527-y

To examine the role of acclimation versus adaptation on the temperature responses of CO₂ assimilation, we measured dark respiration (R n) and the CO₂ response of net photosynthesis (A) in Populus balsamifera collected from warm and cool habitats and grown at warm and cool temperatures. R n and the rate of photosynthetic electron transport (J) are significantly higher in plants grown at 19 versus 27°C; R n is not affected by the native thermal habitat. By contrast, both the maximum capacity of rubisco (V cmax) and A are relatively insensitive to growth temperature, but both parameters are slightly higher in plants from cool habitats. A is limited by rubisco capacity from 17-37°C regardless of growth temperature, and there is little evidence for an electron-transport limitation. Stomatal conductance (g s) is higher in warm-grown plants, but declines with increasing measurement temperature from 17 to 37°C, regardless of growth temperature. The mesophyll conductance (g m) is relatively temperature insensitive below 25°C, but g m declines at 37°C in cool-grown plants. Plants acclimated to cool temperatures have increased R n/A, but this response does not differ between warm- and cool-adapted populations. Primary carbon metabolism clearly acclimates to growth temperature in P. balsamifera, but the ecotypic differences in A suggest that global warming scenarios might affect populations at the northern and southern edges of the boreal forest in different ways.