change in stromule frequency in response to sugar exposure. A) Line plots illustrating changes in SF over time after vacuum infiltration of either 40 mM sugar solution (sucrose, mannitol, sorbitol, fructose or glucose; depicted as black line), or buffer control (APW, depicted as grey line). Error bars represent the 99% confidence intervals. For better comparison, values of the buffer control were plotted along with the sugar treatments. For absolute SF values see additional file 1C. B-C) 'Stacked' and inverted epifluorescence images showing leaf epidermal plastids (black) either 0 h (B) or 2 h (C) after infiltration of 40 mM glucose solution. Note the significantly higher number of plastids having stromules in the image taken at 2 h (C). Size bar corresponds to 10 μm. D) Line plot depicting changes of stromule frequency induced by different sucrose concentrations (1 mM, 10 mM, 40 mM, and 80 mM) as well as by the buffer control (APW). The plots show that increase of sucrose concentration above 40 mM does not result in stronger stromule induction. Error bars represent the 99% confidence intervals. Values for 40 mM and APW have been taken from previously shown experiments (A). E) Line plots with 99% confidence intervals showing the time-course of increase in SF in the presence or absence of translational inhibitors. Leaf samples were pretreated for 1 h (-1 h to 0 h) with APW supplemented with either cycloheximide, DMSO, streptomycin, or spectinomycin. At time point "0 h", all buffers were additionally supplemented with 40 mM sucrose and incubated for additional 3 h. For further details see the legend to A of the same figure.