title: Nitric oxide reduces Cu toxicity and Cu-induced NH4+ accumulation in rice leaves.
abstract: Nitric oxide (NO) is a highly reactive, membrane-permeable free radical, which has recently emerged as an important antioxidant. Here we investigated the protective effect of NO against the toxicity and NH4+ accumulation in rice leaves caused by excess CuSO4 (10mmol L(-1)). It was found that free radical scavengers (sodium benzoate, thiourea, and reduced glutathione) reduced the toxicity and NH4+ accumulation in rice leaves caused by excess CuSO4. NO donor sodium nitroprusside (SNP) was also effective in reducing CuSO4-induced toxicity and NH4+ accumulation in rice leaves. The protective effect of SNP on the toxicity and NH4+ accumulation can be reversed by 2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethyl- imidazoline-1-oxyl-3-oxide, a NO scavenger, suggesting that the protective effect of SNP is attributable to NO released. Results obtained in the present study suggest that reduction of CuSO4-induced toxicity and NH4+ accumulation by SNP is most likely mediated through its ability to scavenge active oxygen species.
authors.affiliation: Department of Agronomy, National Taiwan University, Taipei, Taiwan, China.
authors.forename: Chia Chi
authors.initials: CC
authors.lastname: Yu
authors.forename: Kuo Tung
authors.initials: KT
authors.lastname: Hung
authors.forename: Ching Huei
authors.initials: CH
authors.lastname: Kao
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D003300:Copper / Q000633:toxicity*; D019327:Copper Sulfate / Q000633:toxicity*; D016166:Free Radical Scavengers / Q000494:pharmacology; D009569:Nitric Oxide / Q000502:physiology*; D009599:Nitroprusside / Q000494:pharmacology; D012275:Oryza / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D018515:Plant Leaves / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D010940:Plant Proteins; D000644:Quaternary Ammonium Compounds; D009599:Nitroprusside; D009569:Nitric Oxide; D003300:Copper; D019327:Copper Sulfate