Long Exposure to Salt Stress in Jatropha curcas Leads to Stronger Damage to the Chloroplast Ultrastructure and Its Functionality Than the Stomatal Function

Round 1

Reviewer 1 Report

 

In this manuscript, the authors studied the effects of prolonged salinity stress on J. curcas ultrastructure of stomata and chloroplasts. They observed that stress treatment resulted in important changes in chloroplast as increase in starch granules accumulation causing damage in the granal and stromal grana lamellae as well as imbalance of water conductivity in the xylem associated with changes in stomatal density, stomatal index, and ostiole aperture.

 

In general, it was a very relevant and extensive study, the manuscript was well written and I have only one observation.

 

The authors used three genotypes in this study showing different levels of salt stress tolerance, with CNPAE183, considered tolerant to salinity, and CNPAE218, considered sensitive, and JCAL171 with an intermediate tolerance. However, in the discussion / conclusion the results were not confronted with these features. Was it not possible to found any correlation? I think that authors could clarify this point when discussing their results.

 

Line 316. Was the figure cited correctly? fig. 12 instead fig. 2?

 

 

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

The article is devoted to the study of the effect of prolonged salt stress on the anatomy and architecture of the plant cell of Jatropha curcas. Special attention is paid to the state of chloroplasts and stomata, which play a significant role in stress-resistance of plants, including under salt stress. Much work has been done and significant results have been obtained. Experiments were conducted on 3 genotypes of different ages, differing in salt tolerance, 4 different concentrations of sodium chloride were used, and an original method of maintaining long-term salinity was applied. The stress led to changes in stomatal density, stomatal index, and ostiole aperture. Salinity resulted in a significant increase in starch granules accumulation, leading to destroying chloroplast ultrastructure. Cellular components are characterized by a huge number of indices, which allows to create an informed opinion on the effect of salinity on plant cells. The authors make excellent use of a wide variety of methods to study cell anatomy and cell organelles. A significant feature of this study is prolonged salt stress. On the one hand this is an advantage, on the other hand this approach creates some uncertainties, e.g. due to problems with controlling the growth conditions.

Overall, prestigious results have been obtained which will be useful for the Forests journal. They will bring some certainty to this hotly debated issue.

I would like to make three suggestions to the authors.

In the vast majority of articles on salt stress, the strength of stress is not given in dS m-1 but in mM, e.g. NaCl. This would be more understandable for all readers of this paper, so it would be useful to give these two values simultaneously in the methodological part.

In the title of the paper, the authors talk not only about the ultrastructure but also about the function of chloroplasts and stomata. However, the authors do not cite a single parameter that characterizes the functioning of chloroplasts in their experiments. They make a presumptive conclusion about the possible functioning of chloroplasts only on the basis of changes in the ultrastructure of the organelles. Such a title is beautiful, but in my opinion the functioning of organelles should be removed or authors should talk about functioning with significant reservations.

The article has a huge discussion that probably would have been better shortened.

Author Response

Please see the attached file

Author Response File: Author Response.docx