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Intraspecific variation in thermal acclimation of photosynthesis across a range of temperatures in a perennial crop

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ABSTRACT

Plants acclimate to the thermal regime they experience. We analysed intra-specific variations in the thermal acclimation of photosynthesis in a perennial herbaceous crop by comparing cultivars from contrasting origins grown at a range of temperatures. It was concluded that both temperate and Mediterranean cultivars display strong patterns of thermal acclimation in the 5-40°C range. No evidence of superior performance was found for Mediterranean genotypes at high temperatures.

No MeSH data available.


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Impact of growth temperature on the optimal temperature of net assimilation rate measured at 400 ppm for two alfalfa genotypes of Mediterranean (filled triangles, 7_7 cutting) and temperate (open triangles, G3 cutting) origins. A linear relationship was fitted for each clone and is represented by a dashed line for Mediterranean and a full line for temperate materials. No significant difference was observed between clones. The regression line found across C3 species by Yamori et al. (2014) is also represented (dotted line).
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plw035-F7: Impact of growth temperature on the optimal temperature of net assimilation rate measured at 400 ppm for two alfalfa genotypes of Mediterranean (filled triangles, 7_7 cutting) and temperate (open triangles, G3 cutting) origins. A linear relationship was fitted for each clone and is represented by a dashed line for Mediterranean and a full line for temperate materials. No significant difference was observed between clones. The regression line found across C3 species by Yamori et al. (2014) is also represented (dotted line).

Mentions: Shifts in the optimal temperature of light saturated photosynthesis (Topt) as a function of growth temperature have been reported in a number of C3 species (e.g. Bunce 2000; Mooney 1980; Yamasaki et al. 2002; Yamori et al. 2005) and are central to the thermal acclimation of CO2 assimilation (Yamori et al. 2014). A significant plasticity of Topt was also characterized for alfalfa during our experiments, increasing from about 18 °C for leaves grown at 5–32 °C for leaves grown at 35 °C. Acclimation to low and high temperatures were both covered by this range of conditions. Remarkably, the plasticity of Topt observed in alfalfa alone matched the range of Topt shifts reported by Yamori et al. (2014) across a set of contrasting C3 species (Fig. 7). The average shift in Topt was about 0.48 °C for each 1 °C increase in Tgrowth in both temperate and Mediterranean alfalfa cultivars (no significant genotype effect; y = 0.48*x + 17.4, r2 = 0.85, for the common regression line), as compared with 0.49 °C−1 on average across C3 species (Yamori et al. 2014). Whether this high degree of Topt acclimation is related to the broad geographic distribution of alfalfa and its perennial growth, or whether it is a more general feature of temperate C3 species, still needs to be tested. However, during this study, the same range of Topt variations was observed for both of the genotypes studied, irrespective of their origin. No significant difference was found in the Topt–Tgrowth relationship, suggesting that the ability of a genotype to shift Topt towards actual growth conditions did not necessarily depend upon the environment in which it was selected. Similarly, Pearcy (1977) and Mooney (1980) found identical Topt variations in clones of Atriplex lentiformis and Heliotropum carassivicum collected from contrasting cool coastal and desert habitats. However, these findings differed from those of several other studies which reported differences in the acclimation potential of populations occupying ecological niches with dissimilar thermal regimes (Berry and Bjorkman 1980; Ishikawa et al. 2007).Figure 7.


Intraspecific variation in thermal acclimation of photosynthesis across a range of temperatures in a perennial crop
Impact of growth temperature on the optimal temperature of net assimilation rate measured at 400 ppm for two alfalfa genotypes of Mediterranean (filled triangles, 7_7 cutting) and temperate (open triangles, G3 cutting) origins. A linear relationship was fitted for each clone and is represented by a dashed line for Mediterranean and a full line for temperate materials. No significant difference was observed between clones. The regression line found across C3 species by Yamori et al. (2014) is also represented (dotted line).
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4940478&req=5

plw035-F7: Impact of growth temperature on the optimal temperature of net assimilation rate measured at 400 ppm for two alfalfa genotypes of Mediterranean (filled triangles, 7_7 cutting) and temperate (open triangles, G3 cutting) origins. A linear relationship was fitted for each clone and is represented by a dashed line for Mediterranean and a full line for temperate materials. No significant difference was observed between clones. The regression line found across C3 species by Yamori et al. (2014) is also represented (dotted line).
Mentions: Shifts in the optimal temperature of light saturated photosynthesis (Topt) as a function of growth temperature have been reported in a number of C3 species (e.g. Bunce 2000; Mooney 1980; Yamasaki et al. 2002; Yamori et al. 2005) and are central to the thermal acclimation of CO2 assimilation (Yamori et al. 2014). A significant plasticity of Topt was also characterized for alfalfa during our experiments, increasing from about 18 °C for leaves grown at 5–32 °C for leaves grown at 35 °C. Acclimation to low and high temperatures were both covered by this range of conditions. Remarkably, the plasticity of Topt observed in alfalfa alone matched the range of Topt shifts reported by Yamori et al. (2014) across a set of contrasting C3 species (Fig. 7). The average shift in Topt was about 0.48 °C for each 1 °C increase in Tgrowth in both temperate and Mediterranean alfalfa cultivars (no significant genotype effect; y = 0.48*x + 17.4, r2 = 0.85, for the common regression line), as compared with 0.49 °C−1 on average across C3 species (Yamori et al. 2014). Whether this high degree of Topt acclimation is related to the broad geographic distribution of alfalfa and its perennial growth, or whether it is a more general feature of temperate C3 species, still needs to be tested. However, during this study, the same range of Topt variations was observed for both of the genotypes studied, irrespective of their origin. No significant difference was found in the Topt–Tgrowth relationship, suggesting that the ability of a genotype to shift Topt towards actual growth conditions did not necessarily depend upon the environment in which it was selected. Similarly, Pearcy (1977) and Mooney (1980) found identical Topt variations in clones of Atriplex lentiformis and Heliotropum carassivicum collected from contrasting cool coastal and desert habitats. However, these findings differed from those of several other studies which reported differences in the acclimation potential of populations occupying ecological niches with dissimilar thermal regimes (Berry and Bjorkman 1980; Ishikawa et al. 2007).Figure 7.

View Article: PubMed Central - PubMed

ABSTRACT

Plants acclimate to the thermal regime they experience. We analysed intra-specific variations in the thermal acclimation of photosynthesis in a perennial herbaceous crop by comparing cultivars from contrasting origins grown at a range of temperatures. It was concluded that both temperate and Mediterranean cultivars display strong patterns of thermal acclimation in the 5-40°C range. No evidence of superior performance was found for Mediterranean genotypes at high temperatures.

No MeSH data available.


Related in: MedlinePlus