The following files are available: Table S1. Characteristics of the primers used in this study. Table S2. Complete dataset for physiological variables and metabolite contents. Table S3. Complete dataset for relative gene expression and enzyme activities. Table S4. Statistical comparison of control and drought conditions for the physiological variables and metabolites measured in this study. A "supplemental figures" file containing: Fig. S1. Effect of drought on leaf ontogeny and soil water content. Fig. S2. Stability across samples for the reference genes selected for qPCR analysis. Fig. S3. Stability of the quality control (QC) samples over the different runs of metabolite quantification by UPLC-DAD and GC-FID. Fig. S4. Leaf expansion rate and leaf growth rate during the experiment. Fig. S5. Relative expression of drought-responsive genes. Fig. S6. Relative expression of genes involved in starch metabolism. Fig. S7. Relative expression of genes involved in sucrose metabolism. Fig. S8. Relative expression of P5CS1 genes (proline biosynthesis). Fig. S9. Relative expression of genes involved in nitrogen remobilisation. Fig. S10. Absolute contents for Ala, Asp, GABA, Val, Leu, Ile, Lys, Tyr, Phe and Trp in leaf 11 and leaf 4. Fig. S11. Nitrate and ammonia contents.