Mechanisms of Cadmium Tolerance and Detoxification in Two Ornamental Plants

Round 1

Reviewer 1 Report

The manuscript deals with the assessment of cadmium tolerance in Euryops pectinatus and Gardenia jasminoides. The Authors examined the most important parameters in viewpoint of the plant response to stress induced by heavy metal. Comments are listed below:

L16: justify the premise to conduct this study. Are the soils around Yangtze river contaminated with Cd?

L63-64: indicate the ubiquitous role of antioxidant enzymes in mitigating different abiotic stresses (heavy metals, pesticides). For this purpose, the Authors may refer to the following reference: https://doi.org/10.1007/s00425-022-03838-x

L64-67: rephrase

L146-149: exclude this part from the statistical analysis. Indicate what TI and TF <1 and >1 mean

L167-168: this statement was mentioned above

L249: higher values from 20 mg kg^-1

L256: discussion

L365: do not repeat the results. Give further perspectives of this study

Moderate editing of English language required

Author Response

Dear Editor and reviewers,                                                 

Title: Mechanisms of Cadmium Tolerance and Detoxification in Two Ornamental Plants
Enclosed is the revised version of the paper entitled “Mechanisms of Cadmium Tolerance and Detoxification in Two Ornamental Plants (agronomy-2525294)”. We appreciate the very useful comments from the reviewers. We agree with these suggestions and have revised the manuscript accordingly. Below is our response to their comments resulting in a number of clarifications.
 
Sincerely,

Dr. Yongxiajia Jia, Peixi Yue, Shirong Zhang
Email: [email protected] (Y. Jia), [email protected] (P. Yue), [email protected] (S. Zhang)

Response to Reviewer:

Thanks a lot for having reviewed our manuscript. Now we have revised the manuscript according to the reviewers’ comments. Most of the revisions are in the manuscript. Some explanations regarding the revisions of our manuscript are as follows. The reviewer comments are laid out below in black font and specific concerns have been numbered. Our response is given in red font and changes/additions to the manuscript are given in the blue text.

We appreciate for reviewers’ warm work earnestly, and hope the correction will meet with approval. Once again, thank you very much for your comments and suggestions.

1.L16: justify the premise to conduct this study. Are the soils around Yangtze river contaminated with Cd?

We sincerely thank the reviewer for their valuable feedback that we have used to improve the quality of our manuscript. 

According to the National Soil Pollution Survey Bulletin, 19.4% of the soil point exceeds the standard for cultivated land, and a large range of soil heavy metals exceed that standard in the Yangtze River basin, especially in southwestern and south central China. It is also clear that Cd is among the most important heavy metal pollutants with high toxicity and carcinogenicity, which exceeds the standard limit for China by up to 7.0% in soil samples and throughout the food chain. We have given a brief background in the Abstract.

2.L63-64: indicate the ubiquitous role of antioxidant enzymes in mitigating different abiotic stresses (heavy metals, pesticides). For this purpose, the Authors may refer to the following reference: https://doi.org/10.1007/s00425-022-03838-x

We sincerely appreciate the valuable comments.

Antioxidant enzymes play an important role in enhancing abiotic stress in plants. However, there are many views on the relationship between the change of antioxidant enzyme activity and plant stress resistance. We have carefully read the literature 'Biochemical compounds and stress markers in lettuce upon exposure to pathogenic Botrytis cinerea and fungicides inhibiting oxidative phosphorylation' provided by the reviewer and other literature, and added relevant content in the introduction of the revised manuscript.

3.L64-67: rephrase

As suggested by the reviewer, we have rephrased this sentence.

4.L146-149: exclude this part from the statistical analysis. Indicate what TI and TF <1 and >1 mean.

Thanks for your suggestion. We have put this part into ‘2.8. Calculation of relevant parameters’, and added the meaning of TI and TF > 1.

TI > 1 indicates that the plants are highly tolerant to Cd and can still grow under severe conditions of Cd pollution.

TF> 1 indicates that plants have a strong ability to transport heavy metals from roots to shoots (stems and leaves).

5.L167-168: this statement was mentioned above.

We were really sorry for our careless mistakes. Thank you for your reminder.

6.L249: higher values from 20 mg kg^-1.

We sincerely thank the reviewer for careful reading. As suggested by the reviewer, we have corrected the ‘higher values at 20 mg kg^-1’ into ‘higher values from 20 mg kg^-1’.

7.L256: discussion

We feel sorry for our carelessness. We have corrected the ‘Discuss’ into ‘Discussion’.

8.L365: do not repeat the results. Give further perspectives of this study.

We have re-written this part according to the Reviewer’s suggestion.

The conclusion mainly includes two points. The first is the Cd tolerance and accumulation ability of the two ornamental shrubs, and the second is the Cd tolerance mechanism of the two plants.

9.Comments on the Quality of English Language: Moderate editing of English language required.

 Thank you for your suggestions. According to your advice, this manuscript was edited for proper English language, grammar, punctuation, spelling, and overall style by one or more of the highly qualified native English speaking editors at MogoEdit. The MogoEdit Company specializes in editing and proofreading scientific manuscripts for submission to peer-reviewed journals.

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper entitled 'Mechanisms of Cadmium Tolerance and Detoxification in Two Ornamental Plants' has been reviewed.  The intent of the presented scientific work is good. But authors need to answer some important research questions:-

1. why authors have selected Cd only for the remediation purpose?

2. why authors did not check the uptake capacity of the used plant for some other heavy metals like Hg and As.?

3. Why the authors have selected Euryops pectinatus and Gardenia jasminoides for the phytoremediation purpose? Well justified scientific reasons should be given. There are many plants which can uptake Cd. What is the purpose of using the above two plants only (explain with some good references)? I think, authors tried to explain this question but those explanations are not scientific. Please write your explanation in a separate paragraph of the introduction section.

Some technical comments:

1. Introduction section has not been written in a scientific way. I suggest to do few more literature survey on phytoremediation of other heavy metals and try to find the exact research gap. Add these things in a separate paragraph of the introduction section. Author may take help from the given papers also and try add their data in the current paper with a comparative assessment of the phytoremediation study - 

(a) Kumar, A., Tripti, Raj, D., Maiti, S.K., Maleva, M. and Borisova, G., 2022. Soil pollution and plant efficiency indices for phytoremediation of heavy metal (loid) s: two-decade study (2002–2021). Metals, 12(8), p.1330.

(b) Raj, D. and Maiti, S.K., 2020. Risk assessment of potentially toxic elements in soils and vegetables around coal-fired thermal power plant: A case study of Dhanbad, India. Environmental Monitoring and Assessment, 192(11), p.699.

(c) Yeşilyurt, S., 2023. Phytoremediation Method and Brassica Family: Removal of Chromium, Cadmium and Lead Accumulation with Broccoli (Brassica oleracea var. italica). Results in Chemistry, p.101005.

2. Is there any standard methods of the plant collection? (section - 2.1 of the methodology section). If yes, please give the citation. 

3. Also calculate other indices like Bioaccumulation factor and coefficient. 

4. Calculate the phytoremediation potential of the plant along with the mass balance.

According to the new result modify abstract anf conclusion.

It can be improved.

Author Response

Dear Editor and reviewers,                                                

Title: Mechanisms of Cadmium Tolerance and Detoxification in Two Ornamental Plants
Enclosed is the revised version of the paper entitled “Mechanisms of Cadmium Tolerance and Detoxification in Two Ornamental Plants (agronomy-2525294)”. We appreciate the very useful comments from the reviewers. We agree with these suggestions and have revised the manuscript accordingly. Below is our response to their comments resulting in a number of clarifications.
 
Sincerely,

Dr. Yongxiajia Jia, Peixi Yue, Shirong Zhang
Email: [email protected] (Y. Jia), [email protected] (P. Yue), [email protected] (S. Zhang)

Response to Reviewer:

We feel great thanks for your professional review work on our article. As you are concerned, there are several problems that need to be addressed. According to your nice suggestions, we have made extensive corrections to our manuscript, the relevant instructions are as follows.  The reviewer comments are laid out below in black font and specific concerns have been numbered. Our response is given in red font and changes/additions to the manuscript are given in the blue text.

We appreciate for reviewers’ warm work earnestly, and hope the correction will meet with approval. Once again, thank you very much for your comments and suggestions.

1. why authors have selected Cd only for the remediation purpose?

We sincerely thank the reviewer for their valuable feedback that we have used to improve the quality of our manuscript. 

Cd is a highly toxic heavy metal occurring globally in the environment, especially in China (Koedrith et al., 2013; Wang et al., 2021). An investigation reported that about 7% of soil was polluted with Cd (＞1.0 mg kg^-1) in China during 2005-2013, which is the main culprit of soil pollution. A large range of soil heavy metals exceed that standard in southwestern and south central China (Zhang et al., 2015). The main sources of Cd pollution in soil are untreated industrial waste from smelting, mining and electroplating and excessive use of chemical fertilizers and pesticides (Zhang et al., 2010; Zeng et al., 2020). Excessive Cd in the soil will lead to the retardation of plant root growth, growth of short plants, leaf chlorosis, and a reduction in the yield of agricultural products and their quality (Zeng et al., 2020). In addition, Cd can also affects human health through the food chain. For example, itai-itai disease is a well-known health risk caused by consumption of Cd-contaminated rice (Koji et al., 1983).

Due to the severity and toxicity of Cd pollution, Cd is studied in this paper, and in the introduction added the relevant background knowledge.

[1] Koedrith, P., Kim, H., Weon, J.I., Seo, Y.R.. Toxicogenomic approaches for understanding molecular mechanisms of heavy metal mutagenicity and carcinogenicity. Int. J. Hyg. Environ. Health 2013, 216 (5), 587-598.

[2] Wang, C., Huang, Y., Zhang, C., Zhang, Y., Yuan, K., Xue, W., Liu, Y., Liu, Y., Liu, Z. Inhibition effects of long-term calcium-magnesia phosphate fertilizer application on Cd uptake in rice: Regulation of the iron-nitrogen coupling cycle driven by the soil microbial community. J. Hazard. Mater. 2021, 416, 125916.

[3] Zhang, X.Y., Chen, D.M., Zhong, T.Y., Zhang, X.M., Cheng, M., Li, X.H. Assessment of cadmium (Cd) concentration in arable soil in China. Environ. Sci. Pollut. Res. 2015, 22 (7), 4932-4941.

[4] Zhang, X.; Zhang, S.; Xu, X.; Li, T.; Gong, G.; Jia, Y.; Li,Y.; Deng, L. Tolerance and accumulation characteristics of cadmium in Amaranthus hybridus L. J. Hazard. Mater. 2010, 180, 303-308.

[5] Zeng, J., Li, X., Wang, X., Zhang, K., Wang, Y., Kang, H., Chen, G., Lan, T.,  Zhang, Z., Yuan, S., Wang, C.,  Zhou, Y. Cadmium and lead mixtures are less toxic to the Chinese medicinal plant Ligusticum chuanxiong Hort. Than either metal alone. Ecotoxicology and Environmental Safety, 2020, 193, 110342

[6] Koji, N., Yuichi, Y,; Ryumon, H. The relationship between itai-itai disease among inhabitants of the jinzu river basin and cadmium in rice. Toxicol. Lett. 1983, 17, 263-266.

2. why authors did not check the uptake capacity of the used plant for some other heavy metals like Hg and As.?

We sincerely appreciate the valuable comments.

There are two reasons for this problem. First, as mentioned above, among all heavy metals, Cd is the most severely polluted in China. Secondly, we conducted a large number of accumulator plant screening experiments in the early stage, studied the accumulation ability of various plants to Cd, Pb, Cu, Zn, As, Hg and other elements, and found that E. pectinatus and G. jasminoides, especially G. jasminoides, only had strong tolerance to Cd. The tolerance of plants to heavy metals is the key to the successful implementation of phytoremediation. Therefore, this study only check Cd and did not check other elements.

3. Why the authors have selected Euryops pectinatusand Gardenia jasminoidesfor the phytoremediation purpose? Well justified scientific reasons should be given. There are many plants which can uptake Cd. What is the purpose of using the above two plants only (explain with some good references)? I think, authors tried to explain this question but those explanations are not scientific. Please write your explanation in a separate paragraph of the introduction section.

We think this is an excellent suggestion.

At present, there are few Cd hyperaccumulating plants, and most of these plants produce a small amount of biomass, are only weakly adaptive, and have no ornamental value or practical applications (Krämer, 2010; Reeves et al., 2017). Screening new hyperaccumulators or accumulators with higher biomass and more efficient abilities to transport Cd is the key to phytoremediation (Krämer, 2010; Verbruggen et al., 2008). Ornamental plants generally have features, such as a wide distribution, high adaptability, and large biomasses. If ornamental plants with hyperaccumulative properties can be screened for these features, they may be more economical and valuable for practical applications. Ornamental shrubs with developed roots and large biomass are more efficient at absorbing and accumulating heavy metals than herbaceous ornamental plants. Thus, they are more valuable and practical for phytoremediation.

Euryops pectinatus and Gardenia jasminoides are two common ornamental shrubs in southwest China and even Yangtze River basin, and they are also Cd accumulator plants that we screened in the early stage. They grow quickly and have a large biomass, long flowering period, beautiful plant shapes, and strong ecological adaptability.

Our previous research found that, Gardenia jasminoides can effectively accumulate heavy metals (Zhu, 2018). A field study showed that the plant grew well in the central point of urban waste disposal, and the average concentration of Cd in rhizosphere soil reached 9.28 mg kg^-1. Therefore, Euryops pectinatus and Gardenia jasminoides were selected for phytoremediation.

This point has been added as a separate paragraph in the introduction.

[1] Krämer, U. Metal hyperaccumulation in plants. Annu. Rev. Plant Biol. 2010, 61, 517-534.

[2] Reeves, R.D.; Baker, A.J.M.; Jaffré, T.; Erskine, P.D.; Echevarria, G.; van der Ent, A. A global database for plants that hyperaccumulate metal and metalloid trace elements. New Phytol. 2017, 218, 407-411.

[3] Verbruggen, N.; Hermans,C.; Schat. H. Molecular mechanisms of metal hyperaccumulation in plants. New Phytol. 2008, 181, 759-776.

[4] Zhu Q.Q. Physiological response and enrichment characteristics of Gardenia jasminoides and Gardenia stenophylla to cadmium, lead and zinc contaminated pollution soil. Dissertation, Sichuan Agricultural University, Chengdu, 2018. (In Chinese)

Some technical comments:

1. Introduction section has not been written in a scientific way. I suggest to do few more literature survey on phytoremediation of other heavy metals and try to find the exact research gap. Add these things in a separate paragraph of the introduction section. Author may take help from the given papers also and try add their data in the current paper with a comparative assessment of the phytoremediation study -

(a) Kumar, A., Tripti, Raj, D., Maiti, S.K., Maleva, M. and Borisova, G., 2022. Soil pollution and plant efficiency indices for phytoremediation of heavy metal (loid) s: two-decade study (2002–2021).  Metals, 12(8), p.1330.

(b) Raj, D. and Maiti, S.K., 2020.  Risk assessment of potentially toxic elements in soils and vegetables around coal-fired thermal power plant: A case study of Dhanbad, India.  Environmental Monitoring and Assessment, 192(11), p.699.

(c) Yeşilyurt, S., 2023.  Phytoremediation Method and Brassica Family: Removal of Chromium, Cadmium and Lead Accumulation with Broccoli (Brassica oleracea var. italica).  Results in Chemistry, p.101005.

Thanks for your suggestion.

We have carefully read some literature on phytoremediation of heavy metal-contaminated soils, including the above literature recommended by the reviewers. The introduction is reorganized from the current problems of phytoremediation and the future development direction of phytoremediation.

In the introduction, the phytoremediation is introduced.

2. Is there any standard methods of the plant collection?  (section - 2.1 of the methodology section).  If yes, please give the citation.

According to the reviewers’ comments, we have supplemented this part.

1. pectinatusand G. jasminoideswere provided by Chengdu Huimei Flower Border Horticultural Engineering Co., Ltd. (Chengdu, China), and planted in the Wenjiang Campus of the Sichuan Agricultural University in Sichuan Province, China. They were cultivated from cuttings. Select branches (about 10cm) with good growth and no pests and diseases as cuttings. After the cuttings had rooted, they were cultivated for an additional month. Three seedlings with the same growth potential (plant height 12-15 cm, containing 4-5 leaves) were transplanted to each pot.
2. Also calculate other indices like Bioaccumulation factor and coefficient.

Thanks for your suggestion. We have calculated and supplemented the Bioaccumulation factor.

4. Calculate the phytoremediation potential of the plant along with the mass balance.

Thanks for your suggestion. We have calculated and supplemented the phytoremediation potential.The phytoremediation potential was evaluated using the purification rate (PR). PR is calculated as follows:

PR= (Cd concentration in shoots × dry weight of shoots × the number of plants in one pot / Cd content in soil× soil weight in the pot) × 100%.

5.According to the new result modify abstract anf conclusion.

We have re-written abstract and conclusion according to the Reviewer’s suggestion. Please refer to the revised manuscript for details.

6.Comments on the Quality of English Language: It can be improved.

 Thank you for your suggestions. According to your advice, this manuscript was edited for proper English language, grammar, punctuation, spelling, and overall style by one or more of the highly qualified native English speaking editors at MogoEdit. The MogoEdit Company specializes in editing and proofreading scientific manuscripts for submission to peer-reviewed journals.

Author Response File: Author Response.pdf

Reviewer 3 Report

Authors are advised to recheck the data. In case of table 1 the ca has improved the plant growth parameters rather producing toxic effects on it. Kindly recheck such data which may be misleading.

Authors need to focus the Ms. by putting the molecular mechanism of detoxification of Cd which was missing in the Ms. hence the discussion my be rewritten by incorporating the mechanism and genes involved in toxification.

In introduction a paragraph on cadmium toxicity and its adverse effect oh plant and human health may be added.

Author Response

Dear Editor and reviewers,                                                

Title: Mechanisms of Cadmium Tolerance and Detoxification in Two Ornamental Plants
Enclosed is the revised version of the paper entitled “Mechanisms of Cadmium Tolerance and Detoxification in Two Ornamental Plants (agronomy-2525294)”. We appreciate the very useful comments from the reviewers. We agree with these suggestions and have revised the manuscript accordingly. Below is our response to their comments resulting in a number of clarifications.
 
Sincerely,

Dr. Yongxiajia Jia, Peixi Yue, Shirong Zhang
Email: [email protected] (Y. Jia), [email protected] (P. Yue), [email protected] (S. Zhang)

Response to Reviewer:

We feel great thanks for your professional review work on our article. As you are concerned, there are several problems that need to be addressed. According to your nice suggestions, we have made extensive corrections to our manuscript, the relevant instructions are as follows.  The reviewer comments are laid out below in black font and specific concerns have been numbered. Our response is given in red font and changes/additions to the manuscript are given in the blue text.

We appreciate for reviewers’ warm work earnestly, and hope the correction will meet with approval. Once again, thank you very much for your comments and suggestions.

1. Authors are advised to recheck the data. In case of table 1 the ca has improved the plant growth parameters rather producing toxic effects on it. Kindly recheck such data which may be misleading.

Thanks for your careful checks. Based on your comments, we have rechecked the data and corrected any inaccuracies in the expression.

2. Authors need to focus the Ms. by putting the molecular mechanism of detoxification of Cd which was missing in the Ms. hence the discussion my be rewritten by incorporating the mechanism and genes involved in toxification.

We sincerely thank for your professional review work on our article.

The main mechanisms of detoxification of heavy metals in plants include cell wall binding,  complexation, vacuolar sequestration, efflux and transfer, as well as key genes involved in it. At present, research on genes or protein families related to heavy metal absorption, transportation, detoxification, and efflux, as well as synthesis genes related to cell wall lignin and pectin, have been partially reported in hyperaccumulate plant, rice or Arabidopsis ( Park et al., 2012; Brunetti et al., 2015; Fu et al. 2019; Ashraf et al. 2020; Yanet al. 2022), reveal the mechanism of plant accumulate and detoxification of heavy metals better. During the experiment, only the differences in subcellular distribution, chemical morphology, and antioxidant system between the two ornamental shrubs were analyzed, and the reasons for the differences in tolerance and repair potential between the two plants were preliminarily identified. However, the expression differences of proteins or genes related to Cd absorption, transport, and detoxification were not measured, so the molecular mechanisms of detoxification in the two plants could not be discussed in a targeted manner. Therefore, it was not added in the Discussion. This is the deficiency of this experiment, and it will also be our future research work.

[1]Park, J.; Song, W.Y.; Ko, D.; Eom, Y.; Hansen, T.H.; Schiller, M.; Lee, T. G.; Martinoia, E.; Lee, Y. The phytochelatin transporters AtABCC1 and AtABCC2 mediate tolerance to cadmium and mercury. Plant J. 2012,  69, 278-288.

[2]Brunetti, P.; Zanella, L.; De Paolis, A.; Di Litta, D.; Cecchetti, V.; Falasca, G.; Barbieri, M.; Altamura, M.M.; Costantino, P.; and Cardarelli, M. Cadmium‐inducible expression of the ABC‐type transporter AtABCC3 increases phytochelatin‐mediated cadmium tolerance in Arabidopsis. J. Exp. Bot. 2015, 66, 3815-3829.

[3]Fu, S.; Lu, Y.S.; Zhang, X.; Yang, G.Z.; Chao, D.; Wang, Z.G.; Shi, M.X.; Chen, J.G.; Chao, D.Y.; Li, R.B.; Ma, J.F.; Xia, J.X. The ABC transporter ABCG36 is required for cadmium tolerance in rice. J. Exp. Bot. 2019, 70, 5909-5918.

[4]Ashraf, M.A.; Umetsu, K.; Ponomarenko, O.; Saito, M.; Aslam, M.; Antipova, O.; Dolgova, N.; Kiani, C.D.; Nehzati, S.; Tanoi, K.; Minegishi, K.; Nagatsu, K.; Kamiya, T.; Fujiwara, T.; Luschnig, C.; Tanino, K.; Pickering, I.; George, G.N.; Rahman, A. PIN FORMED 2 modulates the transport of arsenite in Arabidopsis thaliana. Plant Commun. 2020, 1, 100009.

[5]Yan, H.L.; Xu, W.X.; Zhang, T.; Feng, L.; Liu, R.X.; Wang, L.Y.; Wu, L.L.; Zhang, H.; Zhang, X.H.; Li, T.; Peng, Z.M.; Jin, C.; Yu, Y.J.; Ping, J.; Ma, M.; and He, Z.Y. Characterization of a novel arsenite long-distance transporter from arsenic hyperaccumulator fern Pteris vittata. New Phytol. 2022, 233, 2488-2502.

3. In introduction a paragraph on cadmium toxicity and its adverse effect oh plant and human health may be added.

We think this is an excellent suggestion. We have added this to the introduction.

Author Response File: Author Response.pdf

Reviewer 4 Report

An interesting work, but it still needs improvements.

There are many other  concerns and comments that I made within the attached MS pdf file.

Only after minor revisions, this paper can be considered for publication

Comments for author File: Comments.pdf

Author Response

Dear Editor and reviewers,                                                  

Title: Mechanisms of Cadmium Tolerance and Detoxification in Two Ornamental Plants

Enclosed is the revised version of the paper entitled “Mechanisms of Cadmium Tolerance and Detoxification in Two Ornamental Plants (agronomy-2525294)”. We appreciate the very useful comments from the reviewers. We agree with these suggestions and have revised the manuscript accordingly. Below is our response to their comments resulting in a number of clarifications.

Sincerely,

Dr. Yongxiajia Jia, Peixi Yue, Shirong Zhang

Email: [email protected] (Y. Jia), [email protected] (P. Yue), [email protected] (S. Zhang)

Response to Reviewer:

Thanks a lot for having reviewed our manuscript. Now we have revised the manuscript according to the reviewers’ comments. Most of the revisions are in the manuscript. Some explanations regarding the revisions of our manuscript are as follows. The reviewer comments are laid out below in black font and specific concerns have been numbered. Our response is given in red font and changes/additions to the manuscript are given in the blue text.

We appreciate for reviewers’ warm work earnestly, and hope the correction will meet with approval. Once again, thank you very much for your comments and suggestions.

1. L99: it is improperly said... it is correct that every pot is prepared.

Thanks for your reminder. We have corrected the ‘to each pot with or without Cd’ into ‘to each pot that had been prepared’.

2. L147: bibliographic source.

Thanks for your suggestion. We have supplemented the references.

3. Fig1:the caption for both figures? to add the unit of measure ... at first glance it is not clear what those colored borders represent.

Thanks for your careful checks. We have made modifications based on your suggestion, unit of measurement has added to the legend of Fig1.  

4. Fig3: what do these codes represent? are not explained in the text.

We sincerely appreciate the valuable comments. Based on your suggestion, we have changed the x-axis of Fig3. Hoping it explain the meaning clearly now.

5. Fig4: Figure 4a and 4b is not visible...nothing is understood. I recommend restoring it in a way in which all the inserted details can be observed.

We think this is an excellent suggestion, and we have presented Fig4 in a different form. Please refer to the revised manuscript for details.

6. I think lowercase letters are needed.

We feel sorry for our carelessness. We have corrected the capital letters into lowercase letters.

7. Fig6: the figures are of different sizes...I recommend a review of them

Thanks for your careful checks. We have made revisions in the manuscript.

8. L256

We feel sorry for our carelessness. We have corrected the ‘Discuss’ into ‘Discussion’.

9. L272、273

We feel sorry for our carelessness. We have corrected the ‘Sedum alfredii H.’ into ‘Sedum alfredii Hance’.

10. L276：font too big

 We feel sorry for our carelessness. We have corrected this mistake.

11. L286：I recommend that the bibliographic source for the introduction part regarding the part of negative effects, namely the fact that the plant used in this study has a high biomass, can be used as a comparison in this discussion section Sustainable

Ecological Restoration of Sterile Dumps Using Robinia pseudoacacia.

https://doi.org/10.3390/su132414021

We sincerely appreciate the valuable comments. We have carefully read the literature ‘Sustainable Ecological Restoration of Sterile Dumps Using Robinia pseudoacacia’ provided by the reviewer and other literature, and added relevant content in the discussion of the revised manuscript.

12. L365：this part should be developed a little. to specify what is the influence of different concentrations in the accumulation of cadmium in the plant. nothing was mentioned about the tolerance index

We sincerely thanks for your professional review work on our manuscript. Based on your comment, we have re-written conclusions in the revised manuscript. The conclusion mainly includes two points. The first is the Cd tolerance and accumulation ability of the two ornamental shrubs, and the second is the Cd tolerance mechanism of the two plants.

13. L384: quite old bibliographic sources...

Thanks for your reminder. We have replaced some old literature with updated ones.

Author Response File: Author Response.pdf