Figure 3.

Pulse labelling‐derived ¹³C (i.e. excess ¹³C) in ambient controls (AC, black circles) and drought history (DH, grey circles) plots over time in (a) plant shoots, (b) fine root biomass, (c) the proportion of ¹³C excess in fine roots per total plant ¹³C excess (sum of shoot and fine roots), ¹³C excess in (d) fine root respiration (b.d. below detection limit), (e) soil extractable organic C pool (means; n = 3, ± SE, respectively). In (a–e) nonlinear regressions (dashed lines) describe the ¹³C dynamics in AC (black) and DH plots (grey). The grey background indicates samples taken during natural drought; the other samples were taken after subsequent rewetting. Effects of DH treatment and time after labelling were assessed by two‐way repeated‐measures anova; asterisks mark significant differences at single samplings (paired t‐tests, Bonferroni corrected; °P < 0.1; *P < 0.05, **P < 0.01; ***P < 0.001) (See Table 2 and Table S2 for detailed statistical information and model fittings, respectively).