The action of dinaction on volume changes of whole chloroplasts in light and dark.
1. Whole chloroplasts exhibit a fast and strong swelling after addition of dinactin (final concentration 10(-5) m). 2. When illuminated the partieles shrink again and reach their original volume after 15 minutes. ATP may replace the light in this energy-dependent volume reduction. 3. Both swelling and subsequent shrinking are more pronounced in a hypertonic solution of KCl than in a NaCl-medium of the same concentration. 4. These results are discussed in relation to the known ion selectivity of the macrotetralides and the possible presence of light-driven K(+) pump.
Institut für Allgemeine Botanik der Universität Zürich, Zurich, Schweiz.
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E
Bosshard-Heer
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R
Bachofen