title: Exogenous NO depletes Cd-induced toxicity by eliminating oxidative damage, re-establishing ATPase activity, and maintaining stress-related hormone equilibrium in white clover plants.
abstract: Various nitric oxide (NO) regulators [including the NO donor sodium nitroprusside (SNP), the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO), the NO-synthase inhibitor N (G)-nitro-L-Arg-methyl ester (L-NAME), and the SNP analogues sodium nitrite/nitrate and sodium ferrocyanide] were investigated to elucidate the role of NO in white clover (Trifolium repens L.) plants after long-term (5 days) exposure to cadmium (Cd). A dose of 100 μM Cd stress significantly restrained plant growth and decreased the concentrations of chlorophyll and NO in vivo, whereas it disrupted the balance of stress-related hormones and enhanced the accumulation of Cd, thereby inducing reactive oxygen species (ROS) burst. However, the inhibition of plant growth was relieved by 50 μM SNP through its stimulation of ROS-scavenging compounds (ascorbic acid, ascorbate peroxidase, catalase, glutathione reductase, non-protein thiol, superoxide dismutase, and total glutathione), regulation of H(+)-ATPase activity of proton pumps, and increasing jasmonic acid and proline but decreasing ethylene in plant tissues. Even so, the alleviating effect of SNP on plant growth was counteracted by cPTIO and L-NAME and was not observed with SNP analogues, suggesting that the protective roles of SNP are related to the induction of NO. These results suggest that NO may improve the Cd tolerance of white clover plants by eliminating oxidative damage, re-establishing ATPase activity, and maintaining hormone equilibrium. Improving our understanding of the role of NO in white clover plants is key to expanding the plantations to various regions and the recovery of pasture species in the future.
authors.affiliation: Faculty of Landscape Architecture, Sichuan Agricultural University, Chengdu, Sichuan, 611130, People's Republic of China.
authors.forename: S L
authors.initials: SL
authors.lastname: Liu
authors.affiliation: Faculty of Landscape Architecture, Sichuan Agricultural University, Chengdu, Sichuan, 611130, People's Republic of China.
authors.forename: R J
authors.initials: RJ
authors.lastname: Yang
authors.affiliation: Faculty of Landscape Architecture, Sichuan Agricultural University, Chengdu, Sichuan, 611130, People's Republic of China.
authors.forename: Y Z
authors.initials: YZ
authors.lastname: Pan
authors.affiliation: Faculty of Landscape Architecture, Sichuan Agricultural University, Chengdu, Sichuan, 611130, People's Republic of China.|Faculty of Agriculture and Life Sciences, Chungnam National University, Daiden, Daejeon, 305-754, South Korea.
authors.forename: M H
authors.initials: MH
authors.lastname: Wang
authors.affiliation: Faculty of Landscape Architecture, Sichuan Agricultural University, Chengdu, Sichuan, 611130, People's Republic of China.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Faculty of Landscape Architecture, Sichuan Agricultural University, Chengdu, Sichuan, 611130, People's Republic of China.
authors.forename: M X
authors.initials: MX
authors.lastname: Wu
authors.affiliation: Faculty of Landscape Architecture, Sichuan Agricultural University, Chengdu, Sichuan, 611130, People's Republic of China.
authors.forename: J
authors.initials: J
authors.lastname: Hu
authors.affiliation: Institute of Kunming Botany, Chinese Academy of Science (CAS), Kunming, Yunnan, 650201, People's Republic of China.
authors.forename: L L
authors.initials: LL
authors.lastname: Zhang
authors.affiliation: Faculty of Landscape Architecture, Sichuan Agricultural University, Chengdu, Sichuan, 611130, People's Republic of China. 610245498@qq.com.
authors.forename: M D
authors.initials: MD
authors.lastname: Ma
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D060387:Ascorbate Peroxidases / Q000378:metabolism; D001205:Ascorbic Acid / Q000378:metabolism; D001565:Benzoates / Q000494:pharmacology; D002104:Cadmium / Q000633:toxicity*; D002374:Catalase / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D007093:Imidazoles / Q000494:pharmacology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000096:biosynthesis / Q000494:pharmacology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D010937:Plant Growth Regulators / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D012989:Soil Pollutants / Q000633:toxicity*; D013482:Superoxide Dismutase / Q000378:metabolism; D029921:Trifolium / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism
chemical_list: D001565:Benzoates; D007093:Imidazoles; D020030:Nitric Oxide Donors; D010937:Plant Growth Regulators; D017382:Reactive Oxygen Species; D012989:Soil Pollutants; D002104:Cadmium; D002734:Chlorophyll; C079393:1,3-dihydroxy-4,4,5,5-tetramethyl-2-(4-carboxyphenyl)tetrahydroimidazole; D009599:Nitroprusside; D009569:Nitric Oxide; D060387:Ascorbate Peroxidases; D002374:Catalase; D013482:Superoxide Dismutase; D000251:Adenosine Triphosphatases; D005978:Glutathione; D001205:Ascorbic Acid; D019331:NG-Nitroarginine Methyl Ester
keywords: ATPase activity; Cd-induced toxicity; Nitric oxide; Oxidative damage; Stress-related hormones; Trifolium repens L.