Premium
Cation‐induced superoxide generation in tobacco cell suspension culture is dependent on ion valence
Author(s) -
Kawano T.,
Kawano N.,
Muto S.,
Lapeyrie F.
Publication year - 2001
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1046/j.1365-3040.2001.00766.x
Subject(s) - divalent , chemistry , superoxide , nadph oxidase , valence (chemistry) , inorganic chemistry , reactive oxygen species , biochemistry , nuclear chemistry , enzyme , organic chemistry
There have been many reports suggesting the involvement of reactive oxygen species (ROS), including superoxide anion (O 2 .– ), in salt stress. Herein, direct evidence that treatments of cell suspension culture of tobacco ( Nicotiana tabacum L.; cell line, BY‐2) with various salts of trivalent, divalent and monovalent metals stimulate the immediate production of O 2 .– is reported. Among the salts tested, LaCl 3 and GdCl 3 induced the greatest responses in O 2 .– production, whereas CaCl 2 and MgCl 2 showed only moderate effects; salts of monovalent metals such as KCl and NaCl induced much lower responses, indicating that there is a strong relationship between the valence of metals and the level of O 2 .– production. As the valence of the added metals increased from monovalent to divalent and trivalent, the concentrations required for maximal responses were lowered. Although O 2 .– production by NaCl and KCl required high concentrations associated with hyperosmolarity, the O 2 .– generation induced by NaCl and KCl was significantly greater than that induced simply by hyperosmolarity. Since an NADPH oxidase inhibitor, diphenyleneiodonium chloride, showed a strong inhibitory effect on the trivalent and divalent cation‐induced generation of O 2 .– , it is likely that cation treatments activate the O 2 .– ‐generating activity of NADPH oxidase.