the primary nucleus of the green alga acetabularia grows about 25,000-fold in volume while it is separated from the endoplasmic reticulum and the whole cytoplasm by a special paranuclear cisterna of a vacuolar labyrinthum system which shows only very few ( two to six per square micrometer ) and small ( ca . 40-120 nm in diamter ) fenestrations .
C0014239
endoplasmic reticulum
C0010834
cytoplasm