Open AccessChlorophyll catabolism in senescing plant tissues: In vivo breakdown intermediates suggest different degradative pathways for Citrus fruit and parsley leaves
Author(s) -
Dekel Amir-Shapira,
Eliezer E. Goldschmidt,
Arie Altman
Publication year - 1987
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.84.7.1901
Subject(s) - pheophytin , chlorophyll , ethylene , botany , pheophorbide a , chemistry , citrus × sinensis , rutaceae , acetone , biology , horticulture , biochemistry , orange (colour) , photosystem ii , photosynthesis , catalysis
High-pressure liquid chromatography was used to separate chlorophyll derivatives in acetone extracts from senescingCitrus fruit peel, autumnalMelia azedarach L. leaves, and dark-held detached parsley (Petroselinum sativum L.) leaves. Chlorophyllide a and another polar, dephytylated derivative accumulated in large amounts in senescingCitrus peel, particularly in fruit treated with ethylene. Ethylene also induced a 4-fold increase in the specific activity ofCitrus chlorophyllase (chlorophyll chlorophyllidohydrolase, EC 3.1.1.14). Detailed kinetics based on a hexane/acetone solvent partition system showed that thein vivo increase in dephytylated derivatives coincided with the decrease in total chlorophyll. Polar, dephytylated derivatives accumulated also in senescingMelia leaves. Senescing parsley leaves revealed a very different picture. The gradual disappearance of chlorophyll a was accompanied by an increase in pheophytin a and by the transient appearance of several phytylated derivatives. Only pheophytin a and an adjacent peak were left when all the chlorophyll a had disappeared. The pathways for breakdown of chlorophyll in theCitrus and parsley senescence systems are discussed.