title: Nitric oxide is required for hydrogen gas-induced adventitious root formation in cucumber.
abstract: Hydrogen gas (H2) is involved in plant development and stress responses. Cucumber explants were used to study whether nitric oxide (NO) is involved in H2-induced adventitious root development. The results revealed that 50% and 100% hydrogen-rich water (HRW) apparently promoted the development of adventitious root in cucumber. While, the responses of HRW-induced adventitious rooting were blocked by a specific NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt (cPTIO), NO synthase (NOS) enzyme inhibitor N(G)-nitro-l-arginine methylester hydrochloride (l-NAME) and nitrate reductase (NR) inhibitor NaN3. HRW also increased NO content and NOS and NR activity both in a dose- and time-dependent fashion. Moreover, molecular evidence showed that HRW up-regulated NR genes expression in explants. The results indicate the importance of NOS and NR enzymes, which might be responsible for NO production in explants during H2-induced root organogenesis. Additionally, peroxidase (POD) and indoleacetic acid oxidase (IAAO) activity was significantly decreased in the explants treated with HRW, while HRW treatment significantly increased polyphenol oxidase (PPO) activity. In addition, cPTIO, l-NAME and NaN3 inhibited the actions of HRW on the activity of these enzymes. Together, NO may be involved in H2-induced adventitious rooting, and NO may be acting downstream in plant H2 signaling cascade.
authors.affiliation: College of Horticulture, Gansu Agricultural University, Lanzhou 730070, PR China.
authors.forename: Yongchao
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: College of Horticulture, Gansu Agricultural University, Lanzhou 730070, PR China. Electronic address: liaowb@gsau.edu.cn.
authors.forename: Weibiao
authors.initials: W
authors.lastname: Liao
authors.affiliation: College of Horticulture, Gansu Agricultural University, Lanzhou 730070, PR China.
authors.forename: Meng
authors.initials: M
authors.lastname: Wang
authors.affiliation: College of Horticulture, Gansu Agricultural University, Lanzhou 730070, PR China.
authors.forename: Lijuan
authors.initials: L
authors.lastname: Niu
authors.affiliation: College of Horticulture, Gansu Agricultural University, Lanzhou 730070, PR China.
authors.forename: Qingqing
authors.initials: Q
authors.lastname: Xu
authors.affiliation: College of Horticulture, Gansu Agricultural University, Lanzhou 730070, PR China.
authors.forename: Xin
authors.initials: X
authors.lastname: Jin
mesh_terms: D001565:Benzoates / Q000494:pharmacology; D018553:Cucumis sativus / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D016166:Free Radical Scavengers / Q000494:pharmacology; D006859:Hydrogen / Q000494:pharmacology*; D007093:Imidazoles / Q000494:pharmacology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D050901:Nitrate Reductase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D019810:Sodium Azide / Q000494:pharmacology
chemical_list: D001565:Benzoates; D004791:Enzyme Inhibitors; D016166:Free Radical Scavengers; D007093:Imidazoles; D010940:Plant Proteins; C079393:1,3-dihydroxy-4,4,5,5-tetramethyl-2-(4-carboxyphenyl)tetrahydroimidazole; D009569:Nitric Oxide; D006859:Hydrogen; D019810:Sodium Azide; D019001:Nitric Oxide Synthase; D050901:Nitrate Reductase; D019331:NG-Nitroarginine Methyl Ester
keywords: Enzyme; Hydrogen-rich water; NO synthase (NOS); NR genes; Nitrate reductase (NR); Nitric oxide (NO)