On Chlorophyll Breakdown in Senescent Leaves

Abstract

The phytol content of green leaves coincides (±6% on the average) with that calculated on the basis of the chlorophyll present. During senecence, 95% of the chlorophyll may disappear, leaving no trace of colored breakdown products as the leaf turns yellow, brown, or red. In all cases studied, the phytol ester linkage is highly stable during yellowing. The phytol is often recoverable in amounts equivalent to those found in green leaves. The bulk of the nitrogen in petroleum ether extracts from green leaves is associated with the chlorophyll; i.e., the N-phytol mole ratio is close to 4.0. In yellow leaves, this ratio varies from 0.79 to 0.14, higher in fresher leaves, lower in many older ones. The bulk of the chlorophyll nitrogen is now in water or alcohol-soluble form. © 1973, American Chemical Society. All rights reserved.