<Tr> <Td> Structure of chlorophyll a </Td> <Td> Structure of chlorophyll b </Td> <Td> Structure of chlorophyll d </Td> </Tr> <Tr> <Td> Structure of chlorophyll c1 </Td> <Td> Structure of chlorophyll c2 </Td> <Td> Structure of chlorophyll f </Td> </Tr> <P> When leaves degreen in the process of plant senescence, chlorophyll is converted to a group of colourless tetrapyrroles known as nonfluorescent chlorophyll catabolites (NCC's) with the general structure: </P> <P> These compounds have also been identified in several ripening fruits . </P>

A chemical substance that extract chlorophyll from plant cells