Description:
<p>1. Whole chloroplasts exhibit a fast and strong swelling after addition of dinactin (final concentration 10-5 m). 2. When illuminated the particles 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.</p>