title: Protoplasts as a means of studying chloroplast development in vitro.
abstract: Protoplasts obtained enzymically from etiolated primary leaves of oat were illuminated in vitro, and the process of etioplast chloroplast transformation followed. Chloroplast development proceeded up to 6 hours of incubation in the light (20 C). During this period, complete photosynthetic light and dark reactions were constituted, in addition to prolamellar body-degrading protease activity.In parallel, electron microscopic investigations showed a pronounced decrease in prolamellar body area from 89.5 square micrometers at 0 hours to 40.6 square micrometers at 6 hours, whereas the length of the thylakoid membranes (prothylakoids, thylakoids) increased from 21 micrometers at 0 hour to about 293 micrometers at 6 hours. This was accompanied by the formation of grana (bi- and polythylakoids).A comparison of plastid structure and function, developed within isolated protoplasts and those of organelles greened in intact leaves up to 6 hours, showed that there was only a slight lag in development of plastids illuminated in vitro to those illuminated in vivo. However, times of in vitro illumination longer than 6 hours resulted in signs of deterioration and the lack of further development, except for photosystem I activities.
authors: Institut für Botanik, Technische Universität München, Arcisstrasse 21, D-8000 München 2, West Germany.
authors: L F
authors: LF
authors: De Filippis
authors: R
authors: R
authors: Hampp
authors: H
authors: H
authors: Ziegler