Genotype-Dependent Effect of Exogenous Nitric Oxide on Cd-induced Changes in Antioxidative Metabolism, Ultrastructure, and Photosynthetic Performance in Barley Seedlings (Hordeum vulgare)

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  • Fei Chen, Department of Agronomy, College of Agriculture and Biotechnology, Huajiachi Campus, Zhejiang University, China
  • Fang Wang, Department of Agronomy, College of Agriculture and Biotechnology, Huajiachi Campus, Zhejiang University, China
  • Hongyan Sun, Department of Agronomy, College of Agriculture and Biotechnology, Huajiachi Campus, Zhejiang University, China
  • Yue Cai, Department of Agronomy, College of Agriculture and Biotechnology, Huajiachi Campus, Zhejiang University, China
  • Weihua Mao, Department of Agronomy, College of Agriculture and Biotechnology, Huajiachi Campus, Zhejiang University, China
  • Guoping Zhang, Department of Agronomy, College of Agriculture and Biotechnology, Huajiachi Campus, Zhejiang University, China
  • Éva Vincze
  • Feibo Wu, Department of Agronomy, College of Agriculture and Biotechnology, Huajiachi Campus, Zhejiang University, China
  • Molekylær Genetik og Bioteknologi
  • Department of Genetics and Biotechnology
A greenhouse hydroponic experiment was performed using Cd-sensitive (cv. Dong 17) and Cd-tolerant (Weisuobuzhi) barley seedlings to evaluate how different genotypes responded to cadmium (Cd) toxicity in the presence of sodium nitroprusside (SNP), a nitric oxide (NO) donor. Results showed that 5 μM Cd increased the accumulation of O2•-, H2O2, and malondialdehyde (MDA) but reduced plant height, chlorophyll content, net photosynthetic rate (P n), and biomass, with a much more severe response in the Cd-sensitive genotype. Antioxidant enzyme activities increased significantly under Cd stress in the roots of the tolerant genotype, whereas in leaves of the sensitive genotype, superoxide dismutase (SOD) and ascorbate peroxide (APX), especially cytosol ascorbate peroxidase (cAPX), decreased after 5-15 days Cd exposure. Moreover, Cd induces NO synthesis by stimulating nitrate reductase and nitric oxide synthetase-like enzymes in roots/leaves. A Cd-induced NO transient increase in roots of the Cd-tolerant genotype might partly contribute to its Cd tolerance. Exogenous NO dramatically alleviated Cd toxicity, markedly diminished Cd-induced reactive oxygen species (ROS) and MDA accumulation, ameliorated Cd-induced damage to leaf/root ultrastructure, and increased chlorophyll content and P n. External NO counteracted the pattern of alterations in certain antioxidant enzymes induced by Cd; for example, it significantly elevated the depressed SOD, APX, and catalase (CAT) activities in the Cd-sensitive genotype after 10- and 15-day treatments. Furthermore, NO significantly increased stromal APX and Mn-SOD activities in both genotypes and upregulated Cd-induced decrease in cAPX activity and gene expression of root/leaf cAPX and leaf CAT1 in the Cd-sensitive genotype. These data suggest that under Cd stress, NO, as a potent antioxidant, protects barley seedlings against oxidative damage by directly and indirectly scavenging ROS and helps to maintain stability and integrity of the subcellular structure.
Original languageEnglish
JournalJournal of Plant Growth Regulation
Volume29
Issue4
Pages (from-to)394-408
Number of pages15
ISSN0721-7595
DOIs
Publication statusPublished - Dec 2010

    Research areas

  • Barley (Hordeum vulgare L.), Cadmium (Cd), Nitric oxide (NO), Nitric oxide synthase (NOS), ROS metabolism, Ultrastructure

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