title: Nitric oxide contributes to minerals absorption, proton pumps and hormone equilibrium under cadmium excess in Trifolium repens L. plants.
abstract: Nitric oxide (NO) is a stress-signaling molecule in plants that mediates a wide range of physiological processes and responses to metal toxicity. In this work, various NO modulators (NO donor: SNP; NO scavenger: cPTIO; NO synthase inhibitor: l-NAME; and SNP analogs: sodium nitrite/nitrate and sodium ferrocyanide) were investigated to determine the role of NO in Trifolium repens L. plants exposed to Cd. Cd (100μM) markedly reduced biomass, NO production and chlorophyll (Chl a, Chl b and total Chl) concentration but stimulated reactive oxygen species (ROS) and Cd accumulation in plants. SNP (50μM) substantially attenuated growth inhibition, reduced hydrogen peroxide (H2O2) and malonyldialdehyde (MDA) levels, stimulated ROS-scavenging enzymes/agents, and mitigated the H(+)-ATPase inhibition in proton pumps. Interestingly, SNP considerably up-regulated the levels of jasmonic acid (JA) and proline in plant tissues but down-regulated the levels of ethylene (ET) in both shoots and roots and the level of salicylic acid (SA) in roots only, which might be related to the elevated NO synthesis. Additionally, SNP (25-200μM) regulated mineral absorption and, particularly at 50μM, significantly enhanced the uptake of shoot magnesium (Mg) and copper (Cu) and of root calcium (Ca), Mg and iron (Fe). Nevertheless, the effects of SNP on plant growth were reversed by cPTIO and l-NAME, suggesting that the protective effect of SNP might be associated with NO synthesis in vivo. Moreover, SNP analogs did not display roles similar to that of SNP. These results indicated that NO depleted Cd toxicity by eliminating oxidative damage, enhancing minerals absorption, regulating proton pumps, and maintaining hormone equilibrium.
authors.affiliation: College of Landscape Architecture and Ornamental Horticulture, Sichuan Agricultural University, Chengdu 611130, PR China.
authors.forename: Shiliang
authors.initials: S
authors.lastname: Liu
authors.affiliation: College of Landscape Architecture and Ornamental Horticulture, Sichuan Agricultural University, Chengdu 611130, PR China.
authors.forename: Rongjie
authors.initials: R
authors.lastname: Yang
authors.affiliation: College of Landscape Architecture and Ornamental Horticulture, Sichuan Agricultural University, Chengdu 611130, PR China.
authors.forename: Yuanzhi
authors.initials: Y
authors.lastname: Pan
authors.affiliation: College of Landscape Architecture and Ornamental Horticulture, Sichuan Agricultural University, Chengdu 611130, PR China. Electronic address: 610245498@qq.com.
authors.forename: Mingdong
authors.initials: M
authors.lastname: Ma
authors.affiliation: College of Landscape Architecture and Ornamental Horticulture, Sichuan Agricultural University, Chengdu 611130, PR China.
authors.forename: Jiang
authors.initials: J
authors.lastname: Pan
authors.affiliation: College of Landscape Architecture and Ornamental Horticulture, Sichuan Agricultural University, Chengdu 611130, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Life Sciences Division, Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA 94720, USA.
authors.forename: Qingsu
authors.initials: Q
authors.lastname: Cheng
authors.affiliation: College of Landscape Architecture and Ornamental Horticulture, Sichuan Agricultural University, Chengdu 611130, PR China.
authors.forename: Mengxi
authors.initials: M
authors.lastname: Wu
authors.affiliation: College of Landscape Architecture and Ornamental Horticulture, Sichuan Agricultural University, Chengdu 611130, PR China; College of Agriculture and Life Sciences, Chungnam National University, Daejeon 305-754, South Korea.
authors.forename: Maohua
authors.initials: M
authors.lastname: Wang
authors.affiliation: Kunming Botany Institute, Chinese Academy of Science (CAS), Kunming 650201, PR China.
authors.forename: Lin
authors.initials: L
authors.lastname: Zhang
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000704:Analysis of Variance; D000975:Antioxidants / Q000378:metabolism; D002104:Cadmium / Q000378:metabolism / Q000633:toxicity*; D002734:Chlorophyll / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D008315:Malondialdehyde / Q000494:pharmacology; D008903:Minerals / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism / Q000502:physiology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects; D010937:Plant Growth Regulators / Q000378:metabolism*; D018517:Plant Roots / Q000187:drug effects; D017494:Proton Pumps / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D020156:Salicylic Acid / Q000494:pharmacology; D029921:Trifolium / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology
chemical_list: D000975:Antioxidants; D008903:Minerals; D020030:Nitric Oxide Donors; D010937:Plant Growth Regulators; D017494:Proton Pumps; D017382:Reactive Oxygen Species; D002104:Cadmium; D002734:Chlorophyll; D009569:Nitric Oxide; D008315:Malondialdehyde; D006861:Hydrogen Peroxide; D000251:Adenosine Triphosphatases; D020156:Salicylic Acid
keywords: Cadmium excess; Hormone equilibrium; Minerals absorption; Nitric oxide; Proton pumps; Trifolium repens L.