Abscisic acid is a key inducer of hydrogen peroxide production in leaves of maize plants exposed to water stress.
The histochemical and cytochemical localization of water stress-induced H(2)O(2) production in the leaves of ABA-deficient vp5 mutant and wild-type maize (Zea mays L.) plants were examined, using 3,3-diaminobenzidine and CeCl(3) staining, respectively, and the roles of endogenous ABA in the production of H(2)O(2) induced by water stress were assessed. Water stress induced by polyethylene glycol resulted in the accumulation of H(2)O(2) in mesophyll cells, bundle-sheath cells and vascular bundles of wild-type maize leaves, and the accumulation was substantially blocked in the mutant maize leaves exposed to water stress. Pre-treatments with several apoplastic H(2)O(2) manipulators abolished the majority of H(2)O(2) accumulation induced by water stress in the wild-type leaves. The subcellular localization of H(2)O(2) production was demonstrated in the cell walls, xylem vessels, chloroplasts, mitochondria and peroxisomes in the leaves of wild-type maize plants exposed to water stress, and the accumulation of H(2)O(2) induced by water stress in the cell walls and xylem vessels, but not in the chloroplasts, mitochondria and peroxisomes, was arrested in the leaves of the ABA mutant or the ABA biosynthesis inhibitor (tungstate)-pre-treated maize plants. Pre-treatments with the apoplastic H(2)O(2) manipulators also blocked the apoplastic but not the intracellular H(2)O(2) accumulation induced by water stress in the leaves of wild-type plants. These data indicate that under water stress, the apoplast is the major source of H(2)O(2) production and ABA is a key inducer of apoplastic H(2)O(2) production. These data also suggest that H(2)O(2) generated in the apoplast could not diffuse freely into subcellular compartments.
Hu
Xiuli
X
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, PR China.
Zhang
Aying
A
Zhang
Jianhua
J
Jiang
Mingyi
M
D000040:Abscisic Acid / Q000494:pharmacology*; D000975:Antioxidants / Q000378:metabolism; D002374:Catalase / Q000494:pharmacology; D002736:Chloroplasts / Q000187:drug effects / Q000648:ultrastructure; D003890:Desiccation; D006861:Hydrogen Peroxide / Q000378:metabolism*; D008928:Mitochondria / Q000187:drug effects / Q000648:ultrastructure; D009861:Onium Compounds / Q000494:pharmacology; D020675:Peroxisomes / Q000187:drug effects / Q000648:ultrastructure; D018515:Plant Leaves / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism* / Q000648:ultrastructure; D013482:Superoxide Dismutase / Q000494:pharmacology; D014867:Water / Q000378:metabolism*; D003313:Zea mays / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure
D000975:Antioxidants; D009861:Onium Compounds; D014867:Water; C007517:diphenyleneiodonium; D000040:Abscisic Acid; D006861:Hydrogen Peroxide; D002374:Catalase; D013482:Superoxide Dismutase