Model for retrieval from the apoplast, based upon light, confocal, and TEM studies

Water and dissolved substances are carried in the xylem and are offloaded in transpiring photosynthesizing leaves (pathways shown in purple). This involves transfer from the apoplast to the symplast through the pit membrane between metaxylem vessels and xylem parenchyma (shown in the detailed images at lower right). Vesicles formed between the hydrolysed wall and the plasma membrane may carry other substances that are not directly transferable across the membrane, from the apoplast to the symplast, or vice versa, thus effecting a passively driven exchange process across this interface. BS, bundle sheath; MS, mestome sheath; MX, metaxylem; SE, sieve element; STM, sieve tube membrane; TWSE, thick-walled sieve element; VP, vascular parenchyma; XVP, xylem vascular parenchyma.<p><b>Copyright information:</b></p><p>Taken from "A xylem sap retrieval pathway in rice leaf blades: evidence of a role for endocytosis?"</p><p></p><p>Journal of Experimental Botany 2008;59(11):2945-2954.</p><p>Published online 9 Jul 2008</p><p>PMCID:PMC2504346.</p><p>