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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.


Temperature responses of the net assimilation rate at ambient CO2 (A400) for growth temperatures of 5 °C (a), 10 °C (b), 20 °C (c), 25 °C (d), 30 °C (e) and 35 °C (f). Data are presented for two alfalfa cuttings of Mediterranean (filled triangles, 7_7 cutting) and temperate (open triangles, G3 cutting) origins. Lines represent fits of Equation (1). Each point is the average of measurements on three to four mature leaves (node ranks 12–16).
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plw035-F3: Temperature responses of the net assimilation rate at ambient CO2 (A400) for growth temperatures of 5 °C (a), 10 °C (b), 20 °C (c), 25 °C (d), 30 °C (e) and 35 °C (f). Data are presented for two alfalfa cuttings of Mediterranean (filled triangles, 7_7 cutting) and temperate (open triangles, G3 cutting) origins. Lines represent fits of Equation (1). Each point is the average of measurements on three to four mature leaves (node ranks 12–16).

Mentions: The responses of A400 to leaf temperature are presented at the different growth temperatures in Figure 3. A clear shift in the temperature responses of photosynthesis was observed as a function of Tgrowth, affecting both the optimal temperature (Topt) and the net assimilation rate at Topt (A400opt). Over the whole range of growth temperatures, Topt (as determined by fitting a beta function, Equation 1) rose regularly from about 18 °C (for leaves grown at 5 °C) to 35 °C (for leaves grown at 35 °C). An acclimation of the response curve thus occurred in the two genotypes studied, which tended to maximize photosynthetic rates within a temperature range close to the growth temperature. However, A400opt did not remain constant in response to temperature (ANOVA, F5,13 > 7.3, P < 10−2). The maximum rate peaked for leaves grown at 25 °C and was significantly reduced with Tgrowth below 15 °C and above 30 °C. A marked difference in the maximum rates of the two genotypes was observed at a Tgrowth of 35 °C, but not with the other Tgrowth. Significant differences were also observed between the two genotypes relative to photosynthetic rates at high Tleaf (42 °C), the Mediterranean genotype displaying an accentuated decrease at 10, 25 and 30 °C Tgrowh (ANOVA, F1,10 > 4.2, P < 0.05). This resulted in slightly altered shapes of the response curves.Figure 3.


Intraspecific variation in thermal acclimation of photosynthesis across a range of temperatures in a perennial crop
Temperature responses of the net assimilation rate at ambient CO2 (A400) for growth temperatures of 5 °C (a), 10 °C (b), 20 °C (c), 25 °C (d), 30 °C (e) and 35 °C (f). Data are presented for two alfalfa cuttings of Mediterranean (filled triangles, 7_7 cutting) and temperate (open triangles, G3 cutting) origins. Lines represent fits of Equation (1). Each point is the average of measurements on three to four mature leaves (node ranks 12–16).
© Copyright Policy - creative-commons
Related In: Results  -  Collection

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

plw035-F3: Temperature responses of the net assimilation rate at ambient CO2 (A400) for growth temperatures of 5 °C (a), 10 °C (b), 20 °C (c), 25 °C (d), 30 °C (e) and 35 °C (f). Data are presented for two alfalfa cuttings of Mediterranean (filled triangles, 7_7 cutting) and temperate (open triangles, G3 cutting) origins. Lines represent fits of Equation (1). Each point is the average of measurements on three to four mature leaves (node ranks 12–16).
Mentions: The responses of A400 to leaf temperature are presented at the different growth temperatures in Figure 3. A clear shift in the temperature responses of photosynthesis was observed as a function of Tgrowth, affecting both the optimal temperature (Topt) and the net assimilation rate at Topt (A400opt). Over the whole range of growth temperatures, Topt (as determined by fitting a beta function, Equation 1) rose regularly from about 18 °C (for leaves grown at 5 °C) to 35 °C (for leaves grown at 35 °C). An acclimation of the response curve thus occurred in the two genotypes studied, which tended to maximize photosynthetic rates within a temperature range close to the growth temperature. However, A400opt did not remain constant in response to temperature (ANOVA, F5,13 > 7.3, P < 10−2). The maximum rate peaked for leaves grown at 25 °C and was significantly reduced with Tgrowth below 15 °C and above 30 °C. A marked difference in the maximum rates of the two genotypes was observed at a Tgrowth of 35 °C, but not with the other Tgrowth. Significant differences were also observed between the two genotypes relative to photosynthetic rates at high Tleaf (42 °C), the Mediterranean genotype displaying an accentuated decrease at 10, 25 and 30 °C Tgrowh (ANOVA, F1,10 > 4.2, P < 0.05). This resulted in slightly altered shapes of the response curves.Figure 3.

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&deg;C range. No evidence of superior performance was found for Mediterranean genotypes at high temperatures.

No MeSH data available.