PROTONOPHORES AS INDUCERS OF ENERGY DEPENDENT CHANGES IN THE ULTRASTRUCTURE OF WHEAT ROOT CELLS MITOCHONDRIA
O. O. Polygalova, A. A. Ponomareva
Kazan Institute of Biochemistry and Biophysics Kazan Science Center RAS;
e-mail: na.ponomareva@mail.ru
The effects of protonophores, 2, 4-DNP (2, 4-dinitrophenol) and CCCP (carbonyl cyanide m-chlorophenylhydrazone), on plasma membrane potential, release of
K+ into incubation medium, respiratory metabolism, ATP content, and changes in the ultrastructure of cells from excised roots of wheat seedlings were studied.
Dissipation of the plasma membrane potential, release of K+ ions and inhibition of the rate of oxygen consumption by the cells were observed following 1 h
incubation of roots with the protonophores. Mitochondrial had condensed appearance with numerous sharply defined and slightly swollen cristae. The evidence for cytoplasmic
acidification was provided by an increase in plasma membrane potential, a decrease in K+ release into the incubation medium and an increase in ATP content in
the cells after 4 h treatment with the protonophores. The protonophores caused unusual spatial arrangements of cristae in mitochondria, e. g. stacked on the top of each other,
or having the shape of propellers or florets. Such reorganization of cristae might be of adaptive significance in response to increased concentration of H+ in
cytoplasm. After 6 h exposure of the cells to the protonophores, cells ultrastructure destruction started. It is suggested that observed ultrastructural changes in the
mitochondria reflect changes in their functional activity and the physiological state of cells during their long-term exposure to the protonophores.
Key words: Triticum aestivum L., protonophores, ultrastructure, mitochondria, cristae
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