Functional organization of thylakoid membranes in viable pea mutants with low chlorophyll content

Autor: Rubin Ab, N. V. Nizovskaya, G. P. Kukarskikh, Tatyana E. Krendeleva
Rok vydání: 1996
Předmět:
Zdroj: Physiologia Plantarum. 96:439-445
ISSN: 1399-3054
0031-9317
DOI: 10.1111/j.1399-3054.1996.tb00456.x
Popis: The functional organizations of thylakoid membranes from wild type pea (Pisum sativum L. cv. Kapital) and two viable mutants with low chlorophyll (Chl) contents were compared. Nuclear mutations in mutants 7 and 42 led to two- and three-fold decrease in total chlorophyll content, respectively. In spite of low Chl content mutants showed 80% photosynthetic activity, biological productivity, and seed production. It has been shown that mutant membranes differed from that of wild type by Chl distribution between the pigment-protein complexes and by stoichiometry of the main electron-transport complexes. The ratio photosystem I (PSI) : photosystem II (PSII) : cytochrome (Cyt) b 6 /f complex : Chl was 1 :1.1 :1.2 :650 in wild type chloroplasts, 1 :1.8 : 1.7 :600 in mutant 7, and 1 :1.5 :1.9 :350 in mutant 42. PSI- and PSII-dependent electron-transport activities were enhanced in the mutants per mg Chl in proportion to number of reaction centers. The activity of the non-cyclic electron-transport chain increased in proportion to PSII and Cyt b 6 /f complexes. The amount of ATP synthetase per unit of Chl as estimated by H + -ATPase activity was much greater in mutant thylakoids, which is favorable for photosynthetic energy transduction. The low content of the light-harvesting complexes (LHC) in mutants is compensated by an increase of the number of PSII and Cyt b 6 /f complexes, which eliminates the bottleneck at the site of plastoquinone oxidation.
Databáze: OpenAIRE
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