Whole-genome doubling or polyploidy increases plants' tolerance to biotic and abiotic stress. Cadmium (Cd) damages the plant's metabolic system, leading to decreased plant development. The role of tetraploidy and iron nanoparticles (Fe NPs) in minimizing Cd toxicity in rice was investigated in this work. Diploid (E285) and tetraploid (T485) rice lines were treated with Cd (100 μM) and different doses of Fe NPs (0, 10, 25, and 50 mg L⁻¹). The Cd exposure substantially decreased agronomic traits (root and shoot length, shoot and root fresh weight), chlorophyll contents, and antioxidant enzyme activity and increased reactive oxygen species (ROS). The Cd toxicity effect was more pronounced in diploid rice than in tetraploid rice. The application of Fe NPs to Cd-contaminated rice plants reversed the detrimental consequences of Cd in tetraploid and diploid rice cultivars, verified by the substantial upturn in plant growth parameters, chlorophyll contents, decreased ROS, and increased levels of antioxidant enzymes. The Cd uptake was significantly reduced by tetraploidy and Fe NPs, which negatively controlled the expression patterns of Cd transporter genes (like OsNRAMP2 and OsHMA2). The strongest association was seen between diploid rice and cadmium levels in seedlings. Transmission electron microscopy revealed that Cd, especially in diploid rice, caused cell structure damage that Fe NPs and tetraploidy almost repaired. This study demonstrated that tetraploidy and Fe NPs could alleviate Cd toxicity by lowering Cd accumulation, ROS, and cell damage.

中文翻译：

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四倍体和 Fe2O3 纳米颗粒：通过改善氧化应激和下调金属转运蛋白来降低 Cd 诱导的水稻植物毒性的双重策略


全基因组加倍或多倍体增加了植物对生物和非生物胁迫的耐受性。镉 （Cd） 会损害植物的代谢系统，导致植物发育不良。本研究研究了四倍体和铁纳米颗粒 （Fe NPs） 在降低水稻中 Cd 毒性方面的作用。用 Cd （100 μM） 和不同剂量的 Fe NPs （0、10、25 和 50 mg ^L-1） 处理二倍体 （E285） 和四倍体 （T485） 水稻系。Cd 暴露显著降低了农艺性状 （根和芽长度、芽和根鲜重）、叶绿素含量和抗氧化酶活性，并增加了活性氧 （ROS）。二倍体水稻的 Cd 毒性效应比四倍体水稻更明显。将 Fe NPs 应用于 Cd 污染的水稻植物，逆转了 Cd 在四倍体和二倍体水稻品种中的有害后果，植物生长参数、叶绿素含量、ROS 降低和抗氧化酶水平增加的显着提高证实了这一点。四倍体和 Fe NPs 显著降低了 Cd 摄取，负向控制了 Cd 转运蛋白基因 （如 OsNRAMP2 和 OsHMA2） 的表达模式。二倍体水稻与幼苗中镉水平之间的关联最强。透射电子显微镜显示，Cd 尤其是二倍体水稻中的 Cd 会导致细胞结构损伤，Fe、NPs 和四倍体几乎修复。本研究表明，四倍体和 Fe NPs 可以通过降低 Cd 积累、ROS 和细胞损伤来减轻 Cd 毒性。