X-ray microanalytical study of Mn and Fe compartmentation in maize chloroplasts.

X-ray microanalysis of mesophyll and bundle sheath maize chloroplasts showed that bound manganese is located within thylakoids, whereas bound iron is equally present in thylakoids and stroma. A simple correlation between manganese content and oxygen evolution capacity (Photosystem II activity) is unlikely since Mn is also present in bundle sheath thylakoids of low Photosystem II activity. A major part of manganese has probably a distinct function and only a minor part plays a role in the process of oxygen evolution.