peribacteroid membrane

Membrane derived from the plasma membrane of a plant cell and that surrounds the nitrogen-fixing bacteroids in legume root nodules. Has a high lipid content and may regulate the passage of material from the plant cell cytoplasm to the symbiotic bacterial cell. The idea that it restricts leghaemoglobin to the peribacteroid space seems untenable since leghaemoglobin is found in the cytoplasm of some cells.