Research Information System
Bioelectrochemistry, vol.58, no.2, pp.189-191, 2002 (SCI-Expanded, Scopus)
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. © 2002 Published by Elsevier Science B.V.