Abstract:Some photosynthetic characteristics of mutant barley Chlorina f, were studied in comparison with that of normal variety. They were quite different in chlo- roplast membrane structures, pigment protein complexes, the content of electron transport components and photosynthetic functions. The absence of Chlb in mutant barley, as demonstrated by absorption and fluorescence excitation spectra, caused some defects of membrane structure and lose of the ability to regulate the distribution of excitation energy between PSII and PSⅠ. In comparison with the normal variety, the mutant barley contained much less chlorophyll per leaf area, but more P700, Cyt f and PQ on the chlorophyll basis. These differences surely affect their photochemical activities. As envisaged by fluorescence spectra, peripheral antenna of PSⅠ is absent in mutant barley membrane besides the lacking of Chl a/b-protein of PSⅡ. Fluorescence induction transient of mutant barley leaf did not show the typical time course of O→P→S→M→T. The coexistence of light harvesting Chl a/b-protein eomplex of PSⅡ and peripheral antenna of PSI and their cooperation with each other seem to be necessary for the occurence of typical fluorescence induction transient.