Intramembranous particles and chlorophyll complexes in chloroplasts.

The size and population density of large and small particles from freeze-fractured chloroplasts of three wild-type algae and of normal spinach were determined. Computer analyses of low-temperature absorption spectra of chloroplast preparations from these species were performed, and a possible correlation between the occurrence of seven chlorophyll complexes and the aforementioned properties of the intramembranous particles was studies. It was found that only single-sized particles occur in a species containing neither chlorophyll b nor chlorophyll a-685 complexes. The three remaining species carry particles of two sizes, termed large and small particles. However, from quantitative considerations it is concluded that the chlorophyll content of none of the various pigment complexes is related to the size and the population density of the studied particles. If such a relationship exists, it seems likely to be due to the carrier moiety of the chorophyll b-chlorophyll a-685 complex.