INHIBITION OF CHLOROPHYLL SYNTHESIS BY GROWTH RETARDANTS AND COUMARIN, AND ITS REVERSAL BY POTASSIUM

GBOWTH retarding chemicals, including (2-chloroethyl)-trimethylammonium chloride (CCC), N-dimethylamino-succinamic acid (B-Nine), 2,4-dichlorobenzyltributyl-phosphonium chloride (Phosfon D), and coumarin, are known to delay the loss of chlorophyll from leaves kept in the dark1-5 and to stimulate yellowing in light6. Independently of the conditions of illumination, the compounds have inhibited turnover of protein and stimulated turnover of RNA. On this basis it has been suggested that the compounds may inhibit the synthesis of enzymes catalysing both formation and degradation of the chlorophyll6. © 1969 Nature Publishing Group.