Neither phloem nor endodermal cell types are required for production or transmission of the bps1 mobile compound. Top row: shoot and root phenotypes of 15-day Col-0 (left), the phloem-deficient apl (middle), and scarecrow (scr, right). Bottom row: shoot and root phenotypes of bps1 (left), the bps1 apl double mutant (center), and bps1 scr double mutant (right). The double mutants show a leaf arrest phenotype that is similar to that of bps1, indicating that the root-derived mobile compound is still synthesized and transmitted to the shoot. Seedlings shown here were grown at 22°C and photographed at 15 days. Size bars: 1 mm.