Passage of water into the vascular system Once absorbed by osmosis, water needs to pass to the xylem vessels in order to
move up the plant. First it must move across the cortex of the root and through the endodermis before entering the xylem.
• apoplast route, where the water is considered to pass between the cells
• symplast route, where the water is considered to pass via the cytoplasm of the cells via plasmodesmata (cytoplasmic strands connecting one cell to another)
• vacuolar route, where the water is considered to pass through the tonoplast then through the sap vacuole of each cell.
Note the different theories for water transport across the width of the root.