Physiological and Growth Responses of C₃ and C₄ Plants to Reduced Temperature When Grown at Low CO₂ of the Last Ice Age

Abstract

exhibited a large growth advantage over the C 3 species at low [CO 2 ]. However, this advantage was reduced at low temperature, where the C 4 species produced 5× the total mass of the C 3 species versus 14× at the high temperature. This difference was due to a reduction in C 4 growth at low temperature, since the C 3 species exhibited similar growth between temperatures. Physiological differences between temperatures were not detected for either species, although photorespiration/net photosynthesis was reduced in the C 3 species grown at low temperature, suggesting evidence of improved carbon balance at this treatment. This system suggests that C 4 species had a growth advantage over C 3 species during low [ Studying plant responses to global changes of the past provides valuable insights for predicting future responses to a rapidly changing environment (Ward et al. 2005; Edwards et al. 2007; Jackson 2007). In addition, studies involving treatments that simulate past climates provide a baseline for understanding the physiological functioning of plants prior to anthropogenic influences (Polley et al. 1993a,b; Anderson et al. 2001 In addition to physiological models, empirical studies examining the growth and development of C 3 and C 4 species at reduced temperatures and low [CO 2 ] are also needed to better Table 1. The effects of modern and glacial temperatures on total mass (n = 13-14), leaf area (LA, n = 13-14), stomatal conductance (g s , n = 9-12), and specific leaf mass (SLM, n = 13-14) for Abutilon theophrasti (C 3 ) and Amaranthus retroflexus (C 4 ) grown at low CO 2 (200 μmol/mol) for 22 d Values are means ± 1 SE. Data from different chambers within the same treatment were combined because a chamber effect was not detected.Different superscript letters between temperatures and species indicate significant differences at the P < 0.05 level according to ANOVA. ResultsOn an absolute basis, the C 3 (Abutilon) and C 4 species (Amaranthus) exhibited large differences in total mass when grown at low [CO 2 ] (200 μmol/mol) for 22 d. More specifically, the C 4 species had five times the total mass of the C 3 species when grown at the low temperature (22 light/16 dark • C), and almost 14 times the total mass of the C 3 species when grown at the high temperature (30/24 • C; Table 1). In this case, all plants were grown from seed for a total of 22 d, and therefore differences in final biomass mainly reflect differences in relative growth rate (change in biomass per unit biomass per unit time; hereafter RGR). Therefore, the RGR of the C 4 species greatly exceeded that of the C 3 species at low [CO 2 ]. In addition, Amaranthus has inherently small seeds compared with Abutilon, and therefore initial seed size would not have been a factor in producing a relative growth advantage of the C 4 species over the C 3 species when grown at low [CO 2 ]. Furthermore, the C 3 and C 4 species exhibited relative differences in their responses to temperature for total mass and LA (leaf area) (significant species X temperature inte...

Winners always win: growth of a wide range of plant species from low to future high CO2

“…1999; Medeiros and Ward 2013) and temperature (Cowling and Sage 1998; Ward et al. 2008). Indeed, species response to environmental change since the Last Glacial Maximum (LGM) had a greater effect on conifer stand community composition then species response to CO 2 increase (Becklin et al.…”

Global Climate Change, Greenhouse Gases (GHGs) and Cultivated Plants

“…These metabolic events in plants depend on mean temperature, the interaction between water stress and CO 2 (Table 1), and the interaction between ozone and a range of environmental variables. Studies have indicated that the sensitivity of C 3 photosynthesis to temperature declines as plants become limited by CO 2 , much like the patterns exhibited by the C 4 plants (Ward et al, 2008). CO 2 accelerates photosynthesis and its concentration is increasing, the productivity of C 3 plants will not drop (generally) it will increase by 36% (Uzmen, 2007) -compared with 35-80% in the grain legumes (Ziska et al 2001).…”

Changes in the balance between C3 and C4 plants expected in Poland with the global change

“…increase in concentration of CO 2 in the atmosphere will play important role (Gifford 1977;Sionit et al 1981;Rogers et al 1983;Bhattacharya et al 1985;Norby et al 1986;Lindroth et al 1993;Kimball et al 2002). C 4 plants production is only slightly dependant on CO 2 concentration (Curtis et al 1989;Poorter 1993), therefore the crucial role will play the increase of temperature (Kakani & Reddy 2007;Ward Moreover, the deterioration of hygrotermic conditions and nitrogen deficit limit mainly C 3 plants biomass production. C 4 plants, thanks to double mechanism of carbon dioxide fixation, have lower degree of stomata opening, lower transpiration and thus better water use efficiency (WUE) indicator (Sage & Pearcy 1987;Emmerich 2007).…”

“…It is possible that complex of interrelated factors (CO 2 level, temperature, water and nitrogen availability) leads to predominance of both C 4 and C 3 plants. This results from the fact that increase of CO 2 level will prefer C 3 photosynthesis (Gifford 1977;Sionit et al 1981;Rogers et al 1983;Bhattacharya et al 1985;Norby et al 1986;Lindroth et al 1993;Kimball et al 2002), but shift of temperature will stimulate C 4 photosynthesis (Kakani & Reddy 2007;Ward et al 2009). Research conducted in field conditions showed that water or nitrogen deficit can limit positive effects of temperature and CO 2 concentration on primary production (Tissue & Oechel 1987;Diaz et al 1993;Finzi et al 2006;Norby et al 2008), but this effect to concerns mainly production of C 3 plants.…”