Chloroplast Development in Etiolated Peas: Reformation of Prolamellar Bodies in Red Light without Accumulation of Protochlorophyllide

Abstract

Chloroplast development and accumulation of chlorophylls were studied in etiolated peas (Pisum sativum L., cv. Green feast) exposed for 24 h to one of three intensities of red light or to a corresponding intensity of white light producing a similar high medium or low terminal chlorophyll content. Chloroplast development was assessed by counts of grana and partitions per granum in electron micrographs. Chlorophylls were partitioned and protochlorophyllide measured in the unphytylated fraction. More sensitive estimates of protochlorophyllide were made by fluorescence. In the high- and medium-intensity red-light treatments considerable reformation of prolamellar bodies took place during development. This occurred at a stage when no protochlorophyllide would be detected. In the low-intensity treatments reformation was accompanied by an accumulation of protochlorophyllide at a higher level than that obtaining in the dark.