# Lead Tolerance and Enrichment Characteristics of Three Hydroponically Grown Ormamental Plants
## 4 Conclusions  
In conclusion, the growth in the shoots and roots of the three tested ornamental plants was significantly inhibited under Pb stress. As the Pb concentration increased, the root length, root surface area, and root volume of the three tested ornamental plants showed a clear decreasing trend, but the average root diameter of _M. jalapa_ showed a trend that first increased and then decreased. _M. jalapa_ exhibited the strongest tolerance among the three tested ornamental plants. The highest values of Pb content in the shoots were 1074.1 mg/kg, 958.7 mg/kg, and 975.3 mg/kg, indicating that all plants reached the critical level of Pb hyperaccumulators [33]. In addition, the EC values of the tested ornamental plants were the highest in the shoot part of _S. nigrum_ and the root part of _T. patula._ Unfortunately, the TF values were all less than one. Redundancy analysis showed that root architecture changes in the three tested ornamental plants were closely related to the tolerance, accumulation, and transfer ability of the heavy metal Pb. In the hydroponic experiment, the three tested ornamental plants minimized the toxicity of heavy metals to themselves through the plasticity of the root system and the coping strategy of reducing the growth of the root system rather than increasing the accumulation and transfer of heavy metals through a change in the root system's configuration. Therefore, in actual heavy metal-contaminated water and soil environments, various agronomic measures can be taken to improve the tolerance and enrichment capacity by regulating the root biomass and root length of the three test ornamental plants. Whether the hydroponic experiments of the three ornamental plants Pb to different results from soil growth in real environments, these results need to be further verified by potting experiments and in situ experiments. In addition, the ornamental plants examined in this study were also annual ornamental plants. Plants must be sown, cultivated, and regularly watered each year. All of this entails significant expenses. Future studies might look into picking certain perennial ornamental plants or collaborating with local landscape management. This experiment was conceived of and designed by [PERSON] The data from the experiments were collected by [PERSON] and [PERSON] and analyzed by [PERSON] and [PERSON]. ([PERSON]). The reagents, chemicals, materials, and analysis tools were contributed by [PERSON] This paper was written by [PERSON] and modified by all authors. All authors have read and agreed to the published version of the manuscript. This work was supported by the Department Education Science and Technology Research Project of Jilin Provincial (JIKH20210241 KJ), Major Science and Technology Project of Jilin Institute \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Oranamentals Variety** & **Root Morphology Index** & **Explains (\%)** & **F Value** & _p Value_ \\ \hline _T. patula_ & RDW & 68.4 & 28.193 & 0.002 \\  & RL & 16.3 & 2.523 & 0.152 \\  & RS & 12.8 & 1.913 & 0.182 \\  & RV & 11.1 & 1.631 & 0.246 \\  & RAD & 6.8 & 0.945 & 0.332 \\ \hline _S. nigrum_ & RDW & 60.7 & 20.101 & 0.002 \\  & RL & 33.0 & 6.402 & 0.024 \\  & RS & 41.5 & 9.236 & 0.006 \\  & RV & 29.5 & 5.449 & 0.026 \\  & RAD & 43.4 & 9.951 & 0.006 \\ \hline _M. jalapa_ & RDW & 87.1 & 88.122 & 0.002 \\  & RL & 84.8 & 72.766 & 0.002 \\  & RS & 65.2 & 24.315 & 0.002 \\  & RV & 79.2 & 49.537 & 0.002 \\  & RAD & 76.2 & 41.516 & 0.002 \\ \hline \hline \end{tabular} _T. patula, Tegetes patula. S. nigrum, Solanum nigrum and M. jalapa, Mirabilis jalapa._ RDW, root dry weight. RL, root length. RS, root surface area. RV, root volume. RAD, root average diameter.  
\end{table} 
Table 2: Results of permutation test of redundancy analysis (RDA) on predictor variables for the tolerance and enrichment capacity of ornamental plants. of Chemical Technology (2020-012), Chemical Technology Doctoral Start-up Fund Project of Jilin Institute (2021-024), National Natural Science Foundation of China (41471196). Not applicable.