Effect of Magnesium on Chlorophyll‐Protein Complexes

Abstract

AbstractThe effect of Mg2+ during the isolation of chlorophyll‐protein complexes was studied in two moss species (Pleurozium schreberi and Ceratodon purpureus) and New Zealand spinach (Tetragonia expansa). When 2 mM MgCl2 was included in all the extraction and separation phases, the proportions of chlorophyll‐protein complex I. were very small in all plants studied. The withdrawal of Mg2+ considerably increased the proportions of CP I. The most pronounced increase in the chlorophyll present as CP I was found when Mg2+ was withdrawn from the gel, and this also increased the mobility of the CP II complex and free pigment zone. Exclusion of Mg2+ from the running buffer had very little effect. Although Mg2+ had little effect on the relative amount of chlorophyll in CP II, the withdrawal of Mg2+ from all the extraction and separation phases caused formation of polymers of CP II. In the mosses, the formation of polymers of CP II seemed to be more obvious in the species with large grana. Absence of Mg2+ from all the extraction and separation phases sometimes also produced a polymer of CP I.