Endoplasmic reticulum hypertrophy and nuclear envelope formation - a. postulate

Abstract

Dividing endosperm cells of Haemanthus katherinae Bak., treated with 0.025 per cent aqueous solution of a mixture of glycosides from Nerium oleander were examined in vitro in the light and in the electron microscope. A high hypertrophy of endoplasmic reticulum was noted. In prometaphase and metaphase, after treatment for about l h 45 min there appeared very narrow cisternae forming various configurations, frequently in parallel and concentric arrangement. On the membranes of these cisternae there are formed dark areas interpreted as pores characteristic for nuclear envelopes, this indicating that at least part of the two-membrane structures transforms to the nuclear envelope. The formation of the new nuclear envelope pre-maturely and apparently in excess is discussed.