Orientation of the pigment molecules in the chloroplast

Abstract

Dichroism, absorption anisotropy, and anomal dispersion of birefringence were measured in the big lamellate chloroplasts of Mougeotia. The results of these measurements indicate a certain orientation of the chlorophyll molecules, and to a smaller extent, of the carotenoids in the chloroplast.

In species like Funaria, containing relatively small grana-bearing chloroplasts, absorption measurements in polarised light were too unreliable to detect a weak dichroism. However, the anomal dispersion of birefringence was found to be a common phenomenon for all chloroplasts measured.

It may be assumed from these results that a certain orientation of the pigment molecules occurs in all chloroplasts studied.