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Fig. 2 | BMC Biology

Fig. 2

From: Stomatal conductance limited the CO2 response of grassland in the last century

Fig. 2

ci/ca variation during the last century. ci/ca variation for 15-year periods at the beginning (1917–1931) and the end (2004–2018) of the last century (a) and its relationship with δ18Ocellulose variation (b). ci/ca, the ratio of substomatal to atmospheric CO2 concentration, was calculated from the C isotope composition of hay samples using the model of Ma et al. [28] (the “Methods” section). Values represent the yearly averages of samples during the two periods of analysis (1917–1931, filled symbols; 2004–2018, empty symbols). The lines in b (1917–1931, continuous line; 2004–2018, dashed line) and the shaded areas indicate the regression line for the relationship ± CI95%

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