Figure 7.
Effect of induced TPS overexpression on starch mobilization after darkening plants that were previously germinated and grown in continuous light. The empty‐vector control AlcR and the inducible TPS‐overexpressor line (iTPS) were grown from germination in continuous light and temperature (12‐hr/12‐hr light/dark cycle, 160 μmol m−2 s−1 PFD, 21°C). Three weeks after germination, plants were induced by spraying with 2% (v/v) ethanol (indicated by black arrow) and then darkened 2 hr later. Samples were harvested at 4‐hr intervals during the 24 hr prior to darkening and the first 12 hrs after darkening for measurements of: (a) Tre6P, (b) starch, and (c) sucrose. Values are means ± SD (n = 4). Significant differences between AlcR and iTPS, using Student's t test, are indicated by asterisks: *p < 0.05, **p < 0.01, and ***p < 0.001. Expanded plots for starch levels in the first 8 hr after darkening and regressions to estimate the rate of starch mobilization are provided in Supporting Information Figure S6. Time series for clock gene transcripts from the same experiment are shown in Supporting Information Figure S5