Abstract
Many enzymes for chlorophyll degradation are induced during senescence to convert dangerous pigments to safe molecules. The activities of these enzymes should be regulated for the efficient degradation, however, the regulation mechanism is till unknown. We studied the mutant which accumulates chlorophyll degradation products in Arabidopsis. Green leaves of the mutant accumulated 7-hydroxymethyl chlorophyll a which is an intermediate molecule of chlorophyll b to chlorophyll a conversion. When the mutant was subjected to dark treatment to induce senescence, pheophorbide a, a degradation product of chlorophyll a, was accumulated. High-light treatment enhanced the accumulation of 7-hydroxymethyl chlorophyll a in the mutant. It might be due to the stimulation of chlorophyll b to chlorophyll a conversion by the treatment. These results suggest that chlorophyll degradation products are not properly reduced in this mutant. This mutant will be a clue to understanding the regulation mechanism of chlorophyll degradation.
