Dicranopteris linearis is the best-known hyperaccumulator species of rare earth elements (REEs) and silicon (Si), capable of dealing with toxic level of REEs. Hence, this study aimed to clarify how D. linearis leaves cope with excessive REE stress, and whether Si plays a role in REE detoxification. The results show that lanthanum (La – as a representative of the REEs) stress led to decreased biomass and an increase of metabolism related to leaf cell wall synthesis and modification. However, the La stress-induced responses, especially the increase of pectin-related gene expression level, pectin polysaccharides concentration, and methylesterase activity, could be mitigated by Si supply. Approximately 70% of the Si in D. linearis leaves interacted with the cell walls to form organosilicon Si-O-C linkages. The Si-modified cell walls contained more hydroxyl groups, leading to a more efficient REE retention compared to the Si-free ones. Moreover, this [Si-cell wall] matrix increased the pectin-La accumulation capacity by 64%, with no effect on hemicellulose-La and cellulose-La accumulation capacity. These results suggest that [Si-pectin] matrix fixation is key in REE detoxification in D. linearis, laying the foundation for the development of phytotechnological applications (e.g., REE phytomining) using this species in REE-contaminated sites.

Dicranopteris linearis是最著名的稀土元素 (REE) 和硅 (Si) 超富集植物，能够处理毒性水平的 REE。因此，本研究旨在阐明D. linearis叶片如何应对过度的 REE 胁迫，以及 Si 是否在 REE 解毒中发挥作用。结果表明，镧（La——作为稀土元素的代表）胁迫导致生物量减少和与叶细胞壁合成和修饰相关的代谢增加。然而，La 胁迫诱导的反应，特别是果胶相关基因表达水平、果胶多糖浓度和甲酯酶活性的增加，可以通过 Si 供应来减轻。D. linearis中大约 70% 的 Si叶子与细胞壁相互作用形成有机硅 Si-OC 键。Si 修饰的细胞壁含有更多的羟基，与无 Si 的细胞壁相比，导致更有效的 REE 保留。此外，这种 [Si 细胞壁] 基质将果胶-La 积累能力提高了 64%，而对半纤维素-La 和纤维素-La 积累能力没有影响。这些结果表明 [Si-pectin] 基质固定是D. linearis中 REE 解毒的关键，为在 REE 污染地点使用该物种的植物技术应用（例如，REE 植物采矿）的开发奠定了基础。