Fig 4. Isotope ratio mass spectrometric evidence for the occurrence of starch cycling in illuminated leaves through a mechanism involving AGP.

The graphics represent the values of δ¹³C in starch of leaves of (A) 26 DAS WT (Col-0) and aps1 plants, and (B) 22 DAS WT (Ws-2) and pgi1-2 plants exposed to ¹³C enriched CO₂ for 5 hours and then chased for 15 additional hours. Plants were cultured in growth cabinets under long day (LD) conditions. The grey area indicates the ¹³CO₂ pulse period. Starch content in leaves is shown in S4 Fig. Values represent the means ± SE determined from three independent experiments using 6 plants in each experiment.