Photosynthetic and respiratory acclimation and growth response of Antarctic vascular plants to contrasting temperature regimes

• Published in: American Journal of Botany
• Main Authors: Xiong, Fusheng S., Mueller, Erin C., Day, Thomas A.
• Other Authors: National Science Foundation, Arizona State University
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2000
• Subjects: Antarc*; Antarctic; Antarctic Peninsula; Antarctica
• Online Access: http://dx.doi.org/10.2307/2656856; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.2307%2F2656856; https://onlinelibrary.wiley.com/doi/pdf/10.2307/2656856; https://onlinelibrary.wiley.com/doi/full-xml/10.2307/2656856; http://api.wiley.com/onlinelibrary/chorus/v1/articles/10.2307%2F2656856

Air temperatures have risen over the past 50 yr along the Antarctic Peninsula, and it is unclear what impact this is having on Antarctic plants. We examined the growth response of the Antarctic vascular plants Colobanthus quitensis (Caryophyllaceae) and Deschampsia antarctica (Poaceae) to temperature and also assessed their ability for thermal acclimation, in terms of whole‐canopy net photosynthesis ( P n ) and dark respiration ( R d ), by growing plants for 90 d under three contrasting temperature regimes: 7°C day/7°C night, 12°C day/7°C night, and 20°C day/7°C night (18 h/6 h). These daytime temperatures represent suboptimal (7°C), near‐optimal (12°C), and supraoptimal (20°C) temperatures for P n based on field measurements at the collection site near Palmer Station along the west coast of the Antarctic Peninsula. Plants of both species grown at a daytime temperature of 20°C had greater RGR (relative growth rate) and produced 2.2–3.3 times as much total biomass as plants grown at daytime temperatures of 12° or 7°C. Plants grown at 20°C also produced 2.0–4.1 times as many leaves, 3.4–5.5 times as much total leaf area, and had 1.5–1.6 times the LAR (leaf area ratio; leaf area:total biomass) and 1.1–1.4 times the LMR (leaf mass ratio; leaf mass:total biomass) of plants grown at 12° or 7°C. Greater RGR and biomass production at 20°C appeared primarily due to greater biomass allocation to leaf production in these plants. Rates of P n (leaf‐area basis), when measured at their respective daytime growth temperatures, were highest in plants grown at 12°C, and rates of plants grown at 20°C were only 58 ( C. quitensis ) or 64% ( D. antarctica ) of the rates in plants grown at 12°C. Thus, lower P n per leaf area in plants grown at 20°C was more than offset by much greater leaf‐area production. Rates of whole‐canopy P n (per plant), when measured at their respective daytime growth temperatures, were highest in plants grown at 20°C, and appeared well correlated with differences in RGR and total biomass among treatments. C ...