Nocturnal warming increases photosynthesis at elevated CO2 partial pressure in Populus deltoides

• Published in: The New phytologist 2004-03, Vol.161 (3), p.819-826
• Main Authors: Turnbull, Matthew H., Tissue, David T., Murthy, Ramesh, Wang, Xianzhong, Sparrow, Ashley D., Griffin, Kevin L.
• Format: Article
• Language: English
• Subjects: Acclimatization; Animal, plant and microbial ecology; Applied ecology; biochemical feedback mechanisms; Biological and medical sciences; carbohydrate content; Carbon dioxide; cell respiration; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on plants and fungi; elevated CO2; forest trees; Fundamental and applied biological sciences. Psychology; gas exchange; Global warming; Leaves; Metabolism; nocturnal warming; Photosynthesis; Photosynthesis, respiration. Anabolism, catabolism; physiological response; plant ecology; plant physiology; Plant physiology and development; plant response; Plants; Populus deltoides; Populus deltoides (cottonwood); Respiration; starch; Starches; Sugars; temperature; Temperature measurement
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/j.1469-8137.2004.00994.x

• We measured night-time respiration and daytime photosynthesis of leaves in canopies of 4 m tall cottonwood (Populus deltoides) trees to investigate the link between leaf respiration and photosynthetic capacity. • Trees were grown at three CO2 partial pressures [p( CO2) a] (42, 80, 120 Pa) and experimentally exposed to differing nocturnal temperatures (15, 20 or 25°C), but constant daytime temperatures (30-32°C), in a short-term whole-ecosystem environmental manipulation. • Rates of night-time leaf dark respiration (R d) increased significantly at all growth CO2 partial pressures when nocturnal temperatures were increased from 15 to 25°C. Predawn leaf nonstructural carbohydrate (soluble sugars and starch) content was significantly lower at the higher night temperatures. Photosynthetic capacity (A max) during the day increased significantly between 15 and 25°C at 42 and 80 Pa, but not at 120 Pa. • These findings indicate that the previously determined relationships between elevated night-time temperature, dark respiration and increased photosynthetic capacity may also hold at elevated p( CO2) a. This response may have a significant influence on plant and ecosystem carbon exchange under global change scenarios.