School of Environmental and Safety Engineering, Changzhou University, Changzhou, 213164, PR China.
School of Environmental and Safety Engineering, Changzhou University, Changzhou, 213164, PR China; Jiangsu Petrochemical Safety and Environmental Engineering Research Center, Changzhou, 213164, PR China.
Plant Physiol Biochem. 2022 Oct 15;189:104-114. doi: 10.1016/j.plaphy.2022.08.010. Epub 2022 Aug 31.
Cadmium (Cd) and lead (Pb) pollution is a major environmental issue affecting plant production. Spermidine (Spd) is involved in plant response to abiotic stress. However, the role and associated mechanism of Spd under Cd + Pb combined stress are poorly understood. The potential protective role of Spd at different concentration on rice (Oryza sativa L.) seedlings exposed to Cd + Pb treatment was investigated by a hydroponic experiment in this study. The results showed that exogenous Spd enhanced the tolerance of rice seedlings to Cd + Pb stress, resulted in an increase in plant height, root length, fresh weight and dry weight of roots and shoots. Further, application of Spd decreased the contents of hydrogen peroxide, superoxide anion, malondialdehyde, and the accumulation of Cd and Pb, and increased the contents of mineral nutrient, carotenoids, chlorophyll, proline, soluble sugar, soluble protein, total phenol, flavonoid, anthocyanin, and antioxidant enzymes activities in roots and shoots of rice seedlings under Cd + Pb stress. Particularly, 0.5 mmol L Spd was the most effective to alleviate the adverse impacts on growth and physiological metabolism of rice seedlings under Cd + Pb stress. Principal component analysis and heat map clustering established correlations between physio-biochemical parameters and further revealed Spd alleviated Cd + Pb damage in rice seedling was associated with inhibition of accumulation and translocation of Cd and Pb, increasing the contents of photosynthetic pigments and mineral nutrient and stimulation of antioxidative response and osmotic adjustment. Overall, our findings provide an important prospect for use of Spd in modulating Cd + Pb tolerance in rice plants. Spd could help to alleviate Cd + Pb damage through inhibition of accumulation and translocation of Cd and Pb and stimulation of oxidant-defense system and osmotic adjustment.
镉（Cd）和铅（Pb）污染是影响植物生产的主要环境问题。亚精胺（Spd）参与植物对非生物胁迫的响应。然而，Spd 在 Cd+Pb 联合胁迫下的作用及其相关机制还知之甚少。本研究通过水培实验研究了不同浓度的 Spd 对 Cd+Pb 处理下水稻幼苗的潜在保护作用。结果表明，外源 Spd 增强了水稻幼苗对 Cd+Pb 胁迫的耐受性，表现为株高、根长、根和地上部鲜重和干重增加。此外，Spd 的应用降低了 H2O2、超氧阴离子、丙二醛、Cd 和 Pb 的积累，增加了根和地上部矿质营养、类胡萝卜素、叶绿素、脯氨酸、可溶性糖、可溶性蛋白、总酚、类黄酮、花青素和抗氧化酶活性的含量在 Cd+Pb 胁迫下的水稻幼苗。特别是 0.5 mmol·L-1 Spd 对缓解 Cd+Pb 胁迫对水稻幼苗生长和生理代谢的不利影响最为有效。主成分分析和热图聚类建立了生理生化参数之间的相关性，并进一步揭示了 Spd 缓解 Cd+Pb 对水稻幼苗的损伤与抑制 Cd 和 Pb 的积累和转运、增加光合色素和矿质营养的含量以及刺激抗氧化反应和渗透调节有关。总的来说，我们的研究结果为 Spd 调节水稻植物 Cd+Pb 耐受性提供了一个重要的前景。Spd 可以通过抑制 Cd 和 Pb 的积累和转运以及刺激氧化防御系统和渗透调节来帮助缓解 Cd+Pb 损伤。
