Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou 310029, PR China.
Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Saint Lucia, Brisbane 4072, Australia; Centre of Excellence for Plant Success in Nature and Agriculture, Saint Lucia, Brisbane 4072, Australia.
J Hazard Mater. 2024 Dec 5;480:135777. doi: 10.1016/j.jhazmat.2024.135777. Epub 2024 Sep 12.
Cadmium (Cd) is a toxic heavy metal that poses risks to crop production and food safety worldwide. This study evaluated whether manganese (Mn) addition could mitigate Cd toxicity and reduce Cd accumulation in barley seedlings. Hydroponically grown seedlings of Cd-tolerant (WSBZ) and Cd-sensitive (Dong17) barley cultivars were treated with 0.1 μM and 1 μM Cd as well as 0.2 mM Mn alone and in a combination with 0.1 or 1.0 μM Cd for 21 days. Cd exposure caused the dramatic alteration of growth and physiological parameters by disrupting chloroplast, and increased Cd accumulation in both genotypes. However, Mn addition markedly alleviated the negative impacts of all examined parameters caused by Cd stress. Cd addition enhanced expression of anti-oxidative enzyme related genes, including HvSOD, HvCAT, HvAPX, HvPOD in the two barley genotypes exposed to Cd stress. The expression analysis showed nearly all HvNRAMPs genes are dramatically up regulated by both Mn and Cd, with WSBZ having higher expression than Dong 17. Notably, HvNRAMP1 showed the highest expression due to Mn addition, highlighting its crucial role in Mn uptake and transportation in barley. Moreover, Cd stress and Mn addition increased and suppressed the expression of HvYSL5, HvHMA2 and HvHMA3, respectively. Conversely, the expression of HvYSL2, HvIRT1 and HvMTP8 was upregulated by both Mn and Cd treatments, with a further increase observed in the combined Cd and Mn treatments. It may be concluded that sufficient Mn supply is quite important for reducing Cd uptake and accumulation in plants.
镉（Cd）是一种有毒重金属，对全球作物生产和食品安全构成威胁。本研究评估了添加锰（Mn）是否可以减轻 Cd 毒性并减少大麦幼苗中 Cd 的积累。采用水培法培养 Cd 耐受（WSBZ）和 Cd 敏感（Dong17）大麦品种的幼苗，用 0.1 μM 和 1 μM Cd 以及 0.2 mM Mn 单独以及与 0.1 或 1.0 μM Cd 组合处理 21 天。Cd 暴露通过破坏叶绿体导致生长和生理参数的剧烈改变，并增加了两种基因型的 Cd 积累。然而，Mn 添加显著缓解了 Cd 胁迫对所有检查参数的负面影响。Cd 添加增强了暴露于 Cd 胁迫的两个大麦基因型中抗氧化酶相关基因（包括 HvSOD、HvCAT、HvAPX 和 HvPOD）的表达。表达分析表明，几乎所有 HvNRAMPs 基因都被 Mn 和 Cd 显著上调，WSBZ 的表达高于 Dong 17。值得注意的是，由于 Mn 添加，HvNRAMP1 的表达最高，突出了其在大麦中 Mn 摄取和运输中的关键作用。此外，Cd 胁迫和 Mn 添加分别增加和抑制了 HvYSL5、HvHMA2 和 HvHMA3 的表达。相反，HvYSL2、HvIRT1 和 HvMTP8 的表达被 Mn 和 Cd 处理上调，在 Cd 和 Mn 联合处理时进一步增加。可以得出结论，充足的 Mn 供应对于减少植物对 Cd 的摄取和积累非常重要。
