Nitric oxide reduces aluminum toxicity by preventing oxidative stress in the roots of Cassia tora L

• Published in: Plant and cell physiology 2005-12, Vol.46 (12), p.1915-1923
• Main Authors: Wang, Y.S.(Nanjing Agricultural Univ. (China)), Yang, Z.M
• Format: Article
• Language: English
• Subjects: 2-(4-carboxy-2-phenyl)-4; 5-tetramethylinidazoline-1-oxyl-3-oxide; ALUMINIO; ALUMINIUM; Aluminum - analysis; Aluminum - toxicity; Ascorbic Acid - metabolism; Cassia; Cassia - drug effects; Cassia - enzymology; Cassia - physiology; CASSIA TORA; Cassia tora L; CAT; catalase; Catalase - metabolism; cPTIO; Cyclic N-Oxides - pharmacology; Enzyme Activation - drug effects; ESTRES; Histocytochemistry; Imidazoles - pharmacology; Lipid Peroxidation; lipoxygenase; LOX; NBT; NITRIC OXIDE; Nitric Oxide - physiology; Nitric Oxide Donors - pharmacology; nitric oxide synthetase; nitroblue tetrazolium; Nitroprusside - pharmacology; NOS; OXIDACION; OXIDATION; Oxidative Stress; OXIDO NITRICO; OXYDATION; OXYDE NITRIQUE; peroxidase; Peroxidase - metabolism; Plant Roots - chemistry; Plant Roots - growth & development; Plant Roots - physiology; POD; reactive oxygen species; ROS; salicylic acid; SNP; SOD; sodium nitroprusside; STRESS; superoxide dismutase; Superoxide Dismutase - analysis; TBARS; thiobarbituric acid-reactive substances; TOXICIDAD; TOXICITE; TOXICITY
• ISSN: 0032-0781; 1471-9053
• DOI: 10.1093/pcp/pci202

Nitric oxide (NO) as a key signaling molecule has been involved in mediation of various biotic and abiotic stress-induced physiological responses in plants. In the present study, we investigated the effect of NO on Cassia tora L. plants exposed to aluminum (Al). Plants pre-treated for 12 h with 0.4 mM sodium nitroprusside (SNP), an NO donor, and subsequently exposed to 10 muM Al treatment for 24 h exhibited significantly greater root elongation as compared with the plants without SNP treatment. The NO-promoted root elongation was correlated with a decrease in Al accumulation in root apexes. Furthermore, oxidative stress associated with Al treatment increased lipid peroxidation and reactive oxygen species, and the activation of lipoxygenase and antioxidant enzymes was reduced by NO. Such effects were confirmed by the histochemical staining for the detection of peroxidation of lipids and loss of membrane integrity in roots. The ameliorating effect of NO was specific, because the NO scavenger cPTIO [2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethylinidazoline-1-oxyl-3-oxide] completely reversed the effect of NO on root growth in the presence of Al. These results indicate that NO plays an important role in protecting the plant against Al-induced oxidative stress.