Regular paper Chlorophyll-protein complex composition during chloroplast development: A species comparison 1

Barley, maize, pea, soybean, and wheat exhibited differences in chlorophyll a/b ratio and chlorophyll-protein (CP) complex composition during the initial stages of chloro- plast development. During the first hours of greening, the chlorophyll a/b ratios of barley, pea, and wheat were high (a/b >~ 8) and these species contained only the CP complex of photosystem I as measured by mild sodium dodecyl sulfate polyacrylamide gel electro- phoresis. A decrease in chlorophyll a/b ratio and the observation of the CP complexes associated with photosystem II and the light-harvesting apparatus occurred at later times in barley, pea, and wheat. In contrast, maize and soybean exhibited low chlorophyll a/b ratios (a/b < 8) and contained the CP complexes of both photosystem I and the light-harvesting apparatus at early times during chloroplast development. The species differences were not apparent after 8 h of greening. In all species, the CP complexes were stabilized during the later stages of chloroplast development as indicated by a decrease in the percentage of chlorophyll released from the CP complexes during detergent extraction. The results demon- strate that CP complex synthesis and accumulation during chloroplast development may not be regulated in the same way in all higher plant species.