These structures allow companion cells to regulate sieve-tube members in phloem (FLOH-um), and the movement of substances through them is called symplastic transport. These structures occur at densities up to one million per square millimeter in primary pit fields, and they form when the endoplasmic reticulum of a parent cell gets caught in the cell plate during mitosis. Analogous to gap junctions in animal cells, name these cytoplasmic channels 
These structures allow companion cells to regulate sieve-tube members in phloem (FLOH-um), and the movement of substances through them is called symplastic transport. These structures occur at densities up to one million per square millimeter in primary pit fields, and they form when the endoplasmic reticulum of a parent cell gets caught in the cell plate during mitosis. Analogous to gap junctions in animal cells, name these cytoplasmic channels that cross adjacent cell walls, allowing the transfer of molecules between plant cells.
These structures allow companion cells to regulate sieve-tube members in phloem (FLOH-um), and the movement of substances through them is called symplastic transport.
{plasmodesmata}