Chlorophyll formation in cotyledons of Pinus jeffreyi during germination in the dark. Occasional accumulation of protochlorophyll(-ide) forms

Abstract The accumulation of chlorophyll pigments in cotyledons of Pinus jeffreyi during the germination in the dark has been studied by use of low-temperature spectrofluorometry. When Pinus jeffreyi germinates in the dark at 23°C, the cotyledons synthesize chlorophylls; protochlorophyll(-ide) (P-Chl) is usually not accumulated. During germination, different chlorophyll forms appear in accordance with a certain sequence. Exceptionally, P-Chl accumulates in cotyledons grown at 23°C or in cotyledons of seedlings deprived of their roots and maintained in a phosphate buffer at 23°C. It is always present in cotyledons cultivated in darkness at 10°C. When P-Chl accumulates, two forms P-Chl F635 and P-Chl F657 can be distinguished; both are phototransformable. Some comparisons between the P-Chl forms of pine and those of etiolated angiosperms are discussed.