The chlorophylls (Chls), the highly visible and photoactive “green pigments” of plants, are magnesium complexes of a unique macro-cyclic tetra-pyrrole ligand. Breakdown of these green “pigments of life” has attracted profound interest recently. As is established meanwhile, breakdown of chlorophyll in higher plants opens up the macrocycle and rapidly leads to colourless linear tetrapyrroles called “non-fluorescent” catabolites (NCCs). Red and “fluorescent” (slightly yellow) tetrapyrrolic intermediates are proposed to precede the NCCs in the common biochemical pathway, observed in senescent leaves and ripening fruit. However, during chlorophyll breakdown in most plants, photo-chemically interesting coloured or luminescent catabolic intermediates either are elusive or fleetingly existent only.

The lecture will mainly deal with the structures of the new chromophores contained in the Chl catabolites and with the result of preliminary studies of their photochemical properties.

Further reading

Kräutler, B., Hörtensteiner, S. (2006). Chlorophyll Catabolites and the Biochemistry of Chlorophyll Breakdown, in ‘Chlorophylls and Bacteriochlorophylls', (B.Grimm, R.J.Porra, W. Rüdiger, H.Scheer, Eds.), Adv. Photosynthesis & Respiration, vol. 25 (Govindjee, Series Ed.), Springer, Dordrecht, The Netherlands, p. 237-260.

Support by the Austrian National Science Foundation (FWF) is gratefully acknowledged.