THE ULTRASTRUCTURAL ORGANIZATION OF CHLOROPLASTS IN CHLOROTICA MUTANTS OF
PISUM SATIVUM L.
V. G. Ladygin,1 O. B. Vaishlya,2 G. A. Semenova 3
1 Institute of Basic Biological Problems RAS, 142290 Pushchino, Moscow region,
2 Chair of Plant Physiology and Biotechnology, Tomsk State University, 634050 Tomsk, and
3 Institute of Theoretical and Experimental Biophysics RAS, 142290 Pushchino, Moscow region;
e-mail: ladygin@issp.serpukhov.su
A study was made of chlorophyll-protein complexes of photosystems, and of ultrastructural organization of
chloroplasts in pea leaves of the primary cultivar Torsdag and of its mutants, chlorotica 2004 and 2014. It has
been shown that mutants accumulated 80 and 55 % chlorophyll, respectively, and were able to synthesize all four
types of photosystem complexes. The value of the light-harvesting antenna in mutant 2014 was close to the control
one, and in mutant 2004 it increased significantly (by 30%). These changes were caused by a proportional decrease
(40-50%) in any complexes in mutant 2014, whereas the number of PS-I reaction centre complexes, decreased by 50 %
in mutant 2004 at nearly complete storage of PS-I reaction centre complexes, decreased by 50 % in mutant 2004 at
nearly complete storage of PS-II complexes. The proportional decrease of PS-I and PS-II compexes in mutant
chlorotica 2014 was followed by partial reduction of the entire membrane system in chloroplasts, but with a
normal development of both granal and intergranal thylakoids. On the contrary, the loss of PS-I reaction centre
complexes in mutant chlorotica 2004 leads to reduction of unstacked sites of thylakoids in chloroplasts. It is
concluded that this effect may be associated with localization of PS-I complexes mainly in unstacked sites of
thylakoids.
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