Hydroponic experiments were conducted to assess the accumulation, translocation, and chemical forms of lead (Pb) and cadmium (Cd) in the roots, stems, and leaves of Triarrhena sacchariflora seedlings and the associated variation in leaf ultrastructure. The leaves and leaf ultrastructure showed no significant symptoms of toxicity with 0.05 mM Pb or 0.01 mM Cd exposure for 10d. Chlorosis and wilting were observed in leaves when the Pb and Cd concentration was higher than 0.1 and 0.05 mM in the medium, respectively, as demonstrated by severe ultrastructural modifications at higher concentration in the leaves, such as plasmolysis, cell wall detachment, chloroplast swelling, nuclear condensation, and even nuclear fragmentation. The Pb and Cd concentrations in the roots was significantly higher than those in the stems and leaves. This indicated low Pb and Cd translocation from the roots to the aboveground parts. Subcellular distribution analysis showed that the majority of Pb and Cd was bound to the cell wall, especially in the roots, indicating that the cell wall likely constitutes a crucial storage site for Pb and Cd. This mechanism decreases the translocation of Pb and Cd across membranes and is more effective than vacuolar compartmentation. The majority of Pb and Cd exited in form of insoluble Pb/Cd-pectate or -oxalate complexes in the plant. In conclusion, higher concentrations of Pb or Cd induced premature senescence. High Pb and Cd enrichment was observed in the roots, which decreased the translocation of Pb and Cd from the roots to the aboveground tissues. The immobilization of Pb or Cd by the cell wall is important for plant detoxification and can protect protoplasts from Pb or Cd toxicity. Pb and Cd mainly existed in insoluble Pb/Cd-phosphate or -oxalate complexes, exhibiting low activity and thereby limiting symplastic transport and suppressing toxicity.

进行了水培实验，以评估of藜根，茎和叶中铅（Pb）和镉（Cd）的积累，转运和化学形式幼苗及其叶片超微结构的相关变化。叶片和叶片的超微结构在​​0.05 mM Pb或0.01 mM Cd暴露10d时没有显示出明显的毒性症状。当培养基中的Pb和Cd浓度分别高于0.1和0.05 mM时，在叶片中观察到了黄化和枯萎，这表现为在较高浓度的叶片中发生了严重的超微结构修饰，例如溶质分解，细胞壁脱离，叶绿体膨胀，核凝聚，甚至核分裂。根中的Pb和Cd浓度显着高于茎和叶中的Pb和Cd浓度。这表明从根到地上部分的Pb和Cd易位。亚细胞分布分析表明，大多数Pb和Cd结合在细胞壁上，尤其是在根部，表明细胞壁可能构成了Pb和Cd的关键存储位点。这种机制减少了Pb和Cd跨膜的转运，比液泡隔室更有效。植物中的大多数Pb和Cd以不溶性Pb / Cd-果胶或草酸配合物形式存在。总之，较高的Pb或Cd浓度会导致过早衰老。在根部观察到高的Pb和Cd富集，这减少了Pb和Cd从根向地上组织的转运。细胞壁将Pb或Cd固定化对于植物排毒很重要，并且可以保护原生质体免受Pb或Cd的毒性。Pb和Cd主要存在于不溶性Pb / Cd-磷酸盐或草酸盐配合物中，表现出较低的活性，从而限制了共生转运并抑制了毒性。