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

Abstract

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. Colobanthus quitensis exhibited only a slight ability for relative acclimation of P(n) (leaf-area basis) as the optimal temperature for P(n) increased from 8.4° to 10.3° to 11.5°C as daytime growth temperatures increased from 7° to 12° to 20°C. There was no evidence for relative acclimation of P(n) in D. antarctica, as plants grown at all three temperature regimes had a similar optimal temperature (10°C) for P(n). There was no evidence for absolute acclimation of P(n) in either species, as rates of P(n) in plants grown at a daytime temperature of 12°C were higher than those of plants grown at daytime temperatures of 7° or 20°C, when measured at their respective growth temperatures. The poor ability for photosynthetic acclimation in these species may be associated with the relatively stable maritime temperature regime during the growing season along the Peninsula. In contrast to P(n), both species exhibited full acclimation of R(d), and rates of R(d) on a leaf-area basis were similar among treatments when measur...

Photosynthetic and Respiratory Acclimation to Experimental Warming for Four Species in a Tallgrass Prairie Ecosystem

“…In the Great Plains, air temperature is predicted to increase by 2-4 °C with the doubling of current CO 2 concentration (Long and Hutchin 1991). This projected atmospheric warming, combined with the resulting climatic changes, may have marked ecological effects on terrestrial ecosystems, as well as on individual species (Peters and Darling 1985).Both photosynthesis and respiration are temperature Photosynthetic and Respiratory Acclimation to Warming 271 dependent and among the most sensitive processes in response to global warming (Berry and Björkman 1980;Larigauderie and Körner 1995; Atkin et al 2000c;Gunderson et al 2000;Xiong et al 2000;Jarvis et al 2004). A change in temperature will result in an immediate alteration in the rates of each process (Berry and Björkman 1980; Atkin et al 2000c Atkin et al , 2006.…”

“…However, most evidence of photosynthetic and respiratory acclimation to rising temperature comes from laboratory studies with constant day/night temperatures for saplings or seedlings (e.g. Edwards and Smith 1988;Larigauderie and Körner 1995;Gunderson et al 2000;Xiong et al 2000; Bolstad et al 2003;Yamori et al 2005). Very few studies have been performed with small increases in temperature associated with global warming in the natural ecosystems (Bergh and Linder 1999;Loik et al 2000Loik et al , 2004Llorens et al 2004), where daily and seasonal temperatures vary greatly, and no tallgrass species have been included in the previous studies.…”

“…dependent and among the most sensitive processes in response to global warming (Berry and Björkman 1980;Larigauderie and Körner 1995;Atkin et al 2000c;Gunderson et al 2000;Xiong et al 2000;Jarvis et al 2004). A change in temperature will result in an immediate alteration in the rates of each process (Berry and Björkman 1980;Atkin et al 2000cAtkin et al , 2006.…”

Different growth and physiological responses to experimental warming of two dominant plant species Elymus nutans and Potentilla anserina in an alpine meadow of the eastern Tibetan Plateau

“…Thus, prediction of ecosystem responses to climatic warming in a future world strongly relies on our understanding of plant physiological acclimation (Zhou et al 2007). Acclimation of physiological processes has been reported in the literature when plants were exposed to changed temperatures (Edward and Smith 1988, Battaglia et al 1996, Loik et al 2004, Xiong et al 2000, Bolstad et al 2003, Lee et al 2005, Yamori et al 2005. Among physiological parameters, light-saturated photosynthetic rate, apparent quantum yield of the photochemical efficiency of photosystem II and activities of antioxidant enzymes are temperature-dependent and the most sensitive parameters in response to global warming (Atkin et al 2005, Xiong et al 2000, Jarvis et al 2004, Xin and Browse 2000.…”

Growth response and soil–plant water relations of 4 dominant psammophyte species with soil moisture in central Inner Mongolia

“…where w 1 and s 1 are plant dry mass and total leaf area, respectively, at the initial time (t 1 ), and w 2 and s 2 are plant dry mass and total leaf area at the final harvest (t 2 ) (Hunt, 1990;Xiong et al, 2000).…”