Analysis of the Light-harvesting Pigment-Protein Complex of Wild Type and a Chlorophyll-b-less Mutant of Barley

Abstract

Chloroplast lamellae isolated from a chlorophyll-b-less mutant and wild type barley (Hordeum vulgare) were compared. The results demonstrate that: 1 of the 2 major polypeptides comprising the light-harvesting complex (LHC) is present in the cholorphyll-b-less mutant; higher cation concentrations are required to maintain grana stacks in the mutant; and cation effects on excitation energy distribution are present in the chlorophyll-b-less mutant but are reduced in amount and are dependent on higher concentrations of cations. These data are interpreted to support the concept that the LHC mediates cation-induced grana stacking and cation regulation of excitation energy distribution between photosystems I and II in chloroplast lamellae. A partial LHC complement in the mutant alters the quantitative cation requirement for both phenomena, but not the over-all qualitative response.