THE IMMUNOLOCALIZATION OF PLASMA-MEMBRANE H-ATPASE IN THE TRANSFER CELL REGION OF BRASSICA-NAPUS (BRASSICACEAE) OVULES()

Unfertilized mature ovules of Brassica L. contain an abundance of star ch in the integument cells from the micropyle to a plane approximately at the level of the central cell polar nuclei. Inside the Embryo sac central cell, in the coinciding region, there are transfer cell-like w all projections with plasma membranes appressed to their inner surface s. H+-ATPase is present along the inner surfaces of the wall projectio ns as indicated by reactivity with antibody raised against plasma memb rane H+-ATPase. A number of mitochondria are in close association with wall projections in the region of the egg apparatus. Antibody raised against corn plasma membrane H+-ATPase cross reacts with a protein of the same size in extracts of Brassica napus indicating that the two sp ecies contain a similar plasma membrane H+-ATPase.