2Zavoisky Physical-Technical Institute, Kazan Scientific Center of the Russian Academy of Sciences, Sibirskii Tract 10/7, 420029 Kazan, Russia; fax: (843) 272-5075
* To whom correspondence should be addressed.
Received February 4, 2009; Revision received March 27, 2009
Infiltration of wheat (Triticum aestivum L.) seedling leaves with excess of nitrate, nitrite, or the NO donor sodium nitroprusside leads to increase both in content of hydroperoxide and activity of peroxidase and decrease in superoxide dismutase (SOD) activity in the leaf apoplast. Polymorphism of extracellular peroxidases and the presence of Cu/Zn-SOD have been shown in apoplast. Using an ESR assay, a considerable increase in the level of NO following infiltration of leaf tissues with nitrite has been demonstrated. These data suggest development of both oxidative and nitrosative stresses in leaves exposed to high levels of nitrate or nitrite. A possible interplay of NO and reactive oxygen species in plant cells is discussed.
KEY WORDS: wheat, Triticum aestivum L., apoplast, nitrate, nitrite, nitric oxide, hydrogen peroxide, antioxidant enzymes