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. 2011 Jul;62(11):3957-69.
doi: 10.1093/jxb/err095. Epub 2011 Apr 21.

Does Ear C Sink Strength Contribute to Overcoming Photosynthetic Acclimation of Wheat Plants Exposed to Elevated CO2?

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Free PMC article

Does Ear C Sink Strength Contribute to Overcoming Photosynthetic Acclimation of Wheat Plants Exposed to Elevated CO2?

Iker Aranjuelo et al. J Exp Bot. .
Free PMC article

Abstract

Wheat plants (Triticum durum Desf., cv. Regallo) were grown in the field to study the effects of contrasting [CO(2)] conditions (700 versus 370 μmol mol(-1)) on growth, photosynthetic performance, and C management during the post-anthesis period. The aim was to test whether a restricted capacity of sink organs to utilize photosynthates drives a loss of photosynthetic capacity in elevated CO(2). The ambient (13)C/(12)C isotopic composition (δ(13)C) of air CO(2) was changed from -10.2‰ in ambient [CO(2)] to -23.6‰ under elevated [CO(2)] between the 7th and the 14th days after anthesis in order to study C assimilation and partitioning between leaves and ears. Elevated [CO(2)] had no significant effect on biomass production and grain filling, and caused an accumulation of C compounds in leaves. This was accompanied by up-regulation of phosphoglycerate mutase and ATP synthase protein content, together with down-regulation of adenosine diphosphate glucose pyrophosphatase protein. Growth in elevated [CO(2)] negatively affected Rubisco and Rubisco activase protein content and induced photosynthetic down-regulation. CO(2) enrichment caused a specific decrease in Rubisco content, together with decreases in the amino acid and total N content of leaves. The C labelling revealed that in flag leaves, part of the C fixed during grain filling was stored as starch and structural C compounds whereas the rest of the labelled C (mainly in the form of soluble sugars) was completely respired 48 h after the end of labelling. Although labelled C was not detected in the δ(13)C of ear total organic matter and respired CO(2), soluble sugar δ(13)C revealed that a small amount of labelled C reached the ear. The (12)CO(2) labelling suggests that during the beginning of post-anthesis the ear did not contribute towards overcoming flag leaf carbohydrate accumulation, and this had a consequent effect on protein expression and photosynthetic acclimation.

Figures

Fig. 1.
Fig. 1.
Elevated [CO2] effect on wheat flag leaf and ear glucose, sucrose, fructans, and starch content 14 d after anthesis. Open bars correspond to plants grown under ambient CO2 (∼370 μmol mol−1) and closed bars to those grown under elevated CO2 (∼700 μmol mol−1). Each value represents the mean ±SE (n=4). The different symbols indicate non-significant differences (ns), significant differences P<0.05 (*) and P<0.01 (**) between treatments as determined by LSD.
Fig. 2.
Fig. 2.
Elevated [CO2] effect on wheat flag leaf and ear N content and C/N ratio 14 d after anthesis. Open bars correspond to plants grown under ambient CO2 (∼370 μmol mol−1) and closed bars to those grown under elevated CO2 (∼700 μmol mol−1). Otherwise as in Fig. 1.
Fig. 3.
Fig. 3.
Elevated [CO2] effect on wheat flag leaf N, TSP, Rubisco, amino acid content, and Rubisco as a percentage of TSP 14 d after anthesis. Otherwise as in Fig. 1.
Fig. 4.
Fig. 4.
Elevated [CO2] effect on wheat flag leaf total Rubisco activity, Rubisco activation, and Rubisco kcat 14 d after anthesis. Open bars correspond to plants grown under ambient CO2 (∼370 μmol mol−1) and closed bars to those grown under elevated CO2 (∼700 μmol mol−1). Otherwise as in Fig. 1.
Fig. 5.
Fig. 5.
Elevated [CO2] effect on wheat flag leaf and ear 13C isotopic composition (δ13C) in TOM, respired CO2, (DR CO2), TSS, glucose (Glu), sucrose (Suc), fructans (Fru), and starch (HCl-C). A and E stand for ambient and elevated [CO2], respectively, before labelling (pre-labelling period). T0 refers to the end of labelling (labelling period; 14 d after anthesis), whereas T1 and T2 refer to 24 h and 48 h after the end of labelling (post-labelling period), respectively. Otherwise as in Fig. 1.
Fig. 6.
Fig. 6.
Silver-stained two-dimensional gel electrophoresis of proteins extracted from wheat leaves grown under ambient and elevated conditions 14 days after anthesis. In the first dimension, 125 mg of total protein was loaded on a 18 cm IEF strip with a linear gradient of pH 4–7. The second dimension was conducted in 12% polyacrylamide (w/v) gels (20 × 20 cm) (for details see ``Materials and Methods''). The gel image analyses was conducted with Progenesis SameSpots software v3.0 and the subsequent mass spectrometry analyses identified up to 14 proteins (marked by arrows) with significantly different expression in elevated [CO2].

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References

    1. Ainsworth EA, Long SP. What have we learned from 15 years of free-air CO2 enrichment (FACE)? A meta-analytic review of responses of photosynthesis, canopy properties and plant production to rising CO2. New Phytologist. 2005;165:351–372. - PubMed
    1. Ainsworth EA, Rogers A. The response of photosynthesis and stomatal conductance to rising [CO2]: mechanisms and environmental interactions. Plant, Cell and Environment. 2007;30:258–270. - PubMed
    1. Ainsworth EA, Rogers A, Nelson R, Long SP. Testing the ‘source–sink’hypothesis of down-regulation of photosynthesis in elevated [CO2] in the field with single gene substitutions in Glycine max. Agricultural and Forest Meteorology. 2004;122:85–94.
    1. Alonso A, Pérez P, Martínez-Carrasco R. Growth in elevated CO2 enhances temperature response of photosynthesis in wheat. Physiologia Plantarum. 2009;135:109–120. - PubMed
    1. Amthor JS. Effects of atmospheric CO2 concentration on wheat yield: review or results from experiments using various approaches to control CO2 concentration. Field Crop Research. 2001;73:1–34.

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