Genotype-Dependent Effect of Exogenous Nitric Oxide on Cd-induced Changes in Antioxidative Metabolism, Ultrastructure, and Photosynthetic Performance in Barley Seedlings (Hordeum vulgare)
Genotype-Dependent Effect of Exogenous Nitric Oxide on Cd-induced Changes in Antioxidative Metabolism, Ultrastructure, and Photosynthetic Performance in Barley Seedlings (Hordeum vulgare)
复制标题
外源一氧化氮对镉诱导的大麦幼苗抗氧化代谢、超微结构和光合性能变化的基因型依赖性影响
DOI：
10.1007/s00344-010-9151-2
复制
发表时间：
2010-12-01
影响因子：
4.8
通讯作者：
Wu, Feibo
中科院分区：
文献类型：
--
作者：
Chen, Fei;Wang, Fang;Wu, Feibo
温室水培试验中使用镉敏感（cv.以冬17）和耐镉大麦（威索不治）为材料，研究了不同基因型大麦在一氧化氮（NO）供体硝普钠（SNP）存在下对镉（Cd）毒害的反应。结果表明，5 μM Cd处理增加了O2·−、H2 O2和丙二醛（MDA）的积累，但降低了株高、叶绿素含量、净光合速率（Pn）和生物量，Cd敏感基因型的响应更为严重。Cd胁迫下，耐性基因型根系抗氧化酶活性显著升高，而敏感基因型叶片超氧化物歧化酶（SOD）和抗坏血酸过氧化物酶（APX）活性在Cd胁迫5-15 d后显著降低，其中以胞质抗坏血酸过氧化物酶（cAPX）活性下降最为明显。此外，镉诱导NO的合成，通过刺激硝酸还原酶和一氧化氮合成酶在根/叶。镉诱导的NO在根中的短暂增加可能是耐镉基因型的耐镉性的部分原因。外源NO显著减轻了Cd胁迫对叶片和根系的毒害，降低了Cd诱导的活性氧（ROS）和MDA的积累，减轻了Cd对叶片和根系超微结构的损伤，提高了叶绿素含量和净光合速率。外部NO抵消了镉诱导的某些抗氧化酶的变化模式，例如，它显着提高了抑郁症的SOD，APX，和过氧化氢酶（CAT）的活性在镉敏感的基因型后10天和15天的治疗。此外，NO显著提高了两种基因型基质APX和Mn-SOD活性，并上调了Cd诱导的cAPX活性下降以及Cd敏感基因型根/叶cAPX和叶CAT 1基因表达。这些数据表明，在镉胁迫下，NO，作为一种有效的抗氧化剂，保护大麦幼苗免受氧化损伤，直接和间接清除活性氧，并有助于维持亚细胞结构的稳定性和完整性。
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 (Pn), 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 andPn. 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/leafcAPXand leafCAT1in 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.