Phloem unloading in Arabidopsis roots is convective and regulated by the phloem-pole pericycle.

KJO acknowledges the financial support of the BBSRC. We thank Ilya Belevich for preparing material for SBFSEM and Kirsten Knox and Andrea Paterlini for advice on tracer experiments. We thank Pawel Roszak for providing T2 seeds of psAPL::icals3m lines. We thank the Francheschi Microscopy and Imaging center for technical support. This work was supported by National Science Foundation grant IOS-1146500 (MK).