FORMATION OF ASCOSPORE DELIMITING MEMBRANE IN SORDARIA HUMANA

The origin and the formation of the ascospore delimiting membrane in Sordaria humana were studied by electron microscopy. The complete delimiting membrane consists of a double unit membrane system. It originates from tubular elements of 70–100 nm diameter which are formed with a thin membrane 5–6 nm thick and filled with electron translucent materials. The process of development of the delimiting membrane is as follows: Tubular elements first aggregate, and then become arranged in a plane. Soon afterwards, they fuse laterally and become transformed into a delimiting membrane. Spore delimitation starts from the distal end of the centriolar plaque and develops towards the opposite side of the nucleus, preceding the formation of the membrane system.