Symplastic transport of Lucifer Yellow in mature leaf blades of barley: potential mesophyll‐to‐sieve‐tube transfer

SUMMARY Intermediate veins of mature barley leaves were exposed by partial enzymic removal of mesophyll cells. Lucifer Yellow was iontophoresed into a variety of cell types and its symplastic transfer followed by fluorescence microscopy. Dye transfer from mesophyll cells into the parenchymatous bundle sheath (PBS) and from PBS to mestome sheath (MS) occurred readily. Dye transfer around and along both PBS and MS was rapid. Following injection into PBS or MS dye could be seen moving within sieve tubes, thus providing a demonstration of potential mesophyll‐to‐sieve tube transfer.