Trees are considered good candidates for phytoremediation of soils contaminated with trace elements (TE), e.g. mine tailings. Using two year-old Tilia cordata plants, we demonstrated the nature and the scale of root architecture, especially root apices, as an indicator of mining sludge toxicity and plant capability to cope with these stress conditions. The novelty of our research is the analysis of the root response to substrate with extremely high concentrations of numerous toxic TE, and the 3D illustration of the disorders in root apex architecture using a clarity technique for confocal microscopy.

The analysis demonstrates (1) a marked reduction in the size of the root apex zones (2) the occurrence of vascular tissues abnormally close to the root apex (3) collapse of the internal tissues in many root apices. Simultaneously, at the cellular level we observed some signs of a defensive response - such as a common increase of cell wall (CW) thickness and the formation of local CW thickenings - that enlarge the CW capacity for TE sequestration. However, we also detected harmful effects. Among others, a massive deposition of TE in the middle lamella which caused major damage - probably one of the reasons why the inner tissues of the root apex often collapsed – and the formation of incomplete CWs resulting in the occurrence of extremely large cells. Moreover, many cells of the root apex exhibited degenerated protoplasts.

All these alterations indicate the harsh conditions for lime growth and survival and simultaneously, the manifestation of a defensive response.

The obtained results allowed us to conclude that analysis of the nature and scale of structural alterations in roots can be useful indicators of plant ability to cope with stress conditions, e.g. in prospect of using the examined plants for reclamation of soils contaminated with TE.

树木被认为是植物修复被微量元素（TE）污染的土壤（例如矿山尾矿）的良好候选者。我们使用了两年前的紫ilia植物，证明了根系结构的性质和规模，尤其是根尖，作为采矿污泥毒性和植物应对这些胁迫条件的能力的指标。我们研究的新颖性是使用共聚焦显微镜的清晰度技术分析极高浓度的多种有毒TE对底物的根系反应，以及3D图解说明根尖构架中的疾病。

分析表明（1）根尖区的大小显着减少（2）异常靠近根尖的血管组织的发生（3）在许多根尖中内部组织的塌陷。同时，在细胞水平上，我们观察到防御反应的一些迹象-例如细胞壁（CW）厚度的普遍增加和局部CW增厚的形成-扩大了TE隔离的CW能力。但是，我们还检测到有害影响。除其他外，TE在中层中大量沉积，这造成了严重破坏（这可能是根尖内部组织经常塌陷的原因之一），并且不完整的CW形成导致了非常大的细胞的出现。此外，根尖的许多细胞表现出变性的原生质体。

所有这些变化表明了石灰生长和生存的苛刻条件，同时也表明了防御反应的表现。

所获得的结果使我们得出结论，即分析根部结构改变的性质和规模可以作为植物应对胁迫条件的有用指标，例如，在使用被检植物复垦被TE污染的土壤的前景中。