Figure 1.

Illustration of a wheat plant and the stable isotope composition (‰) of δ²H, δ¹⁸O, and δ¹³C of different plant parts (flag leaves, ears, and roots) sampled at mid-grain-filling, plus mature kernels (grains) and the water (blue drops) from the basal part of the stems, flag leaves, and developing grains. Values presented are means from the DM of five representative plants per plot and including all treatments. We measured δ¹³C DM in 108 plots (five cultivars and four landraces, four growing conditions, and three replicates); whereas we measured δ¹⁸O DM and δ²H DM in 48 plots (two cultivars and two landraces, four growing conditions, and three replicates) during the 2010 crop cycle. The δ¹⁸O and δ²H of the water extracted from the flag leaves were analyzed in a subset of two cultivars and two landraces (with three replicates) under fertilized conditions and two water regimes (18 plots; landraces in SI conditions were discarded due to lodging). We measured δ¹⁸O and δ²H in water from the stems, developing grains and DM in a subset of five cultivars and five landraces (with three replicates) under fertilized conditions and two water regimes (45 plots; landraces were discarded due to lodging under SI conditions; see “Materials and Methods” section). Analyses of water extracted from different tissues were performed in samples from the 2011 crop season.