Figure 2.

Schematic diagram of Cd transport in rice nodes. OsHMA2, localized in the phloem parenchyma and companion cells of both enlarged and diffuse vascular bundles in stem nodes, mediates the loading of Cd into the phloem for the preferential distribution to the upper nodes and panicle. OsZIP7, localized in both xylem and phloem parenchyma cells of the enlarged vascular bundles, can transport the Cd from xylem to phloem and unload Cd from xylem to parenchyma cell bridge. OsLCT1, localized in parenchyma cell bridge and phloem parenchyma cells of diffuse vascular bundles, mediates the intervascular transfer of Cd and promotes the transport of Cd to the grain through phloem. OsCCX2, localized in the xylem parenchyma cells of enlarged and diffuse vascular bundles, mediates the loading of Cd into the xylem and promotes Cd transport into grains.