Effect of Circadian Rhythm Change on Chlorophyll Biosynthesis in Chlorophytum capense

The process of chlorophyll biosynthesis is catalyzed by a series of enzymes and strictly regulated in angiosperms. In this paper, the effect of the circadian rhythm on chlorophyll biosynthesis in Chlorophytum capense (L.) Kuntze was investigated, and the diurnal variations of 14 precursors following changes in the circadian rhythm were monitored. Results showed that ALA ( δ-aminolaevulinic acid), PBG (porphobilinogen), Proto Ⅸ(protoporphyrin Ⅸ), heme, Mg-Proto Ⅸ(Mg-protoporphyrin Ⅸ), Chlide a (chlorophyllide a), Chlide b (chlorophyllide b), chlorophyll a and chlorophyll b were induced by light.Urogen Ⅲ(uroporphyrin Ⅲ), Coprogen Ⅲ(coproporphyrin Ⅲ) and Pchlide(protochlorophyllide)were induced by darkness, in particular Pchlide accumulation increased significantly in the dark. Both Mpe (Mg-proto monomethyl ester) and Mpde (Mg-protoporphyrin Ⅸ diester) had two accumulation peaks at 12:00 and 24:00, respectively. This paper demonstrated that chlorophyll biosynthesis was significantly regulated by the circadian rhythm, but different precursors followed different rules.