Two types of kinetics of membrane potential of water plant leaves illuminated by ultraviolet light.
Bioelectrochemistry
; 58(2): 189-91, 2002 Dec.
Article
em En
| MEDLINE
| ID: mdl-12414325
ABSTRACT
The effects of ultraviolet-B (UV-B) radiation on plasma membrane of water plant (Elodea canadensis, Vallisneria spiralis) cells were investigated by using microelectrode methods. A fast and reversible depolarization of membrane potential occurs initially during exposure of leaf cells to UV on a white light background, after which a slow phase of depolarization sets in. On action series, UV is pulsed for 15 s, with dark interval of 3 min, no monotonous response of systems on the UV excitation is observed. The action spectrum of the fast UV response lies in the interval of 300-330 nm and that of the slow phase-in the interval of 280-300 nm. The input impedance of membranes remains unchanged during the period of exposure. It is concluded that the H(+)-extruding complex of plant cell plasma membranes really consists of two types of interrelated electronic H(+)-pumps an H(+)-pump of redox-active nature and the H(+)-pump of the H(+)-ATPase enzyme complex. Clearly, during the exposure of leaf cells to UV light, initially, the H(+)-pump of redox-active nature and then H(+)-ATPase are inhibited. It is proposed that the initial chromophore of UV-B light on plasma membrane can be one of the components of H(+)-pump of redox-active nature. It is probably the molecular of quinone.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Raios Ultravioleta
/
Hydrocharitaceae
/
Potenciais da Membrana
Idioma:
En
Revista:
Bioelectrochemistry
Assunto da revista:
BIOQUIMICA
Ano de publicação:
2002
Tipo de documento:
Article
País de afiliação:
Azerbaidjão