ddPCR analysis of GPT1 transcript levels (A) and starch content (B) in sepals, stamen, and carpels of wild-type (WT) and gpt1-3 flowers at opening. A, ddPCR values are means of measurements of three biological replicates normalized to 10,000 molecules of IPP2. B, Starch content values are means of measurements of four biological replicates. Error bars indicate se. Asterisks denote a highly significant value (***, P < 0.01). The inset in A is a ddPCR analysis of GPT1 transcript levels in single biological samples of cauline leaves and whole flowers.