The Effect of Guttation on the Growth of Bamboo Shoots

Round 1

Reviewer 1 Report

The presented manuscript describes an interesting study on guttation in moso bamboo and the study deserves well to be published. However, there are various problematic text passages and shortcomings, including problems with the images. The manuscript needs to be markedly improved and overhauled. Below, there is a list with specific comments on these issues. Particularly, the microscopic images (despite the circumstance that the microscopic preparations are of good quality) do not really allow to recognize details and in the discussion section, data are discussed which were not provided and described in the results.

 

 

List of comments

 

Page 1, line 9: “... exudating liquid droplets from the…“ Either “droplets“ or “liquid“ would be sufficient.

 

Page 2, line 75: “…using the dewdrops…“ Dew is not guttation. Here, the authors should be specific whether dewdrops or guttation drops were present on the leaves.

Page 2, lines 78-79 : “… with liquid exudate collected and stored in a 50 mL centrifuge tube using a syringe and its volume recorded.“ By using this method: Was there any liquid left on the leaves?

Page 2, lines 90-92: Probably, cut samples were placed in the staining solution with their cut ends? This needs to be described more clearly (in some few sentences).

Page 3, lines 97-98: “… and fixed in an FAA liquid (Formaldehyde: acetic acid: ethanol = 5 : 5 : 90) and extract the gas from the sample with a vacuum pump.“ This should be explained more clearly. Suggestion: … and air was extracted from the samples by placing them into a vessel equipped with a vacuum pump.

Page 3, line 105: “…filed…“ … selected in the field…

Page 5, Figure 2: Figure 2 B is a table and should be presented as such. Furthermore, there is no statistic information provided for the values in this table (supposedly, these are mean values?), neither for the guttation volume (no standard deviation) and also not for temperature and humidity (here, data ranges might be appropriate).

Figure 2 C: Here, the water content oft he sheath blade is presented as a histogram. However, it was not described, how the water content was determined. Also, statistical significance of the differences between day-night should be given.

Page 5, lines 158 – 159: This sentence belongs to “Material and Methods“.

Page 6, Figure 3: The legend is incomplete and ambiguous. What does “Part of a substance“ mean?

Page 6, line 174: Chapter heading: water transport instead of “water transportation”

Page 6, line 179: “… along the vascular bundles, whose was also observed…“ … which were also observed…

Page 7, lines 204-205: parenchyma

Page 6, lines 181-186 and Page 7, Figure 4 G: The authors describe the anatomical differences between cross sections taken from internodes at different heights. It is not quite clear whether these are due to different ontogenetic stages or if the structure of the internodes change with height. Furthermore, the authors refer to “nuclei” of “vascular bundle cells”. Which cells are meant here? This section should be improved, or – alternatively – cancelled.

Page 7, lines 189 -  199 and Figure 5: Here, anatomy of sheath and leaves is described. The microscopic preparations are of high quality. The presented images, however, do not allow to recognize details as described in the text: they are too small and the magnification is partly not high enough. The authors should provide more detailed images with higher magnification, and  there should be more lettering to indicate observed structures in all images. Additionally, it would be of high interest to provide and describe detailed images of hydathodes to determine if their structure corresponds to that of other plants (as mentioned in the discussion section line 248).  

Page 8, lines 217-218: This sentence should be improved.

Page 9, Fig. 6B and C: On these images, guttation is not really recognizable, there should be more detailed photos. Fig. 6D: the lettering “CK”, “all” and so on: it is not clear, what that means. These different groups should be clearly explained in the figure legend. Also, standard deviations should be provided in the figure.

 Page 10, lines 245 - 257: Here, different types of hydathodes as can be found in plants are described. However, there is no information on the hydathodes structure of the considered species. It is strongly recommended to close this gap and provide a description of hydathodes of moso.

Page 10, lines 257 - 259: The authors report that “We observed many vascular bundles in the culm sheath, especially in the sheath blade, where there are more xylem ducts apparent in a vascular bundle and their cross-sectional area exceeds that of the phloem. “ It is necessary to provide these data, including statistics.

Page 10, line 262: “…many stomata and hydathodes were observed on its surface. “ Also here, data are described which are not provided in the results section.

Page 10, lines 264 - 267: The authors claim that the structural damage after removing the culm sheath would be due to a large amount of liquid loss (as far as I understand the text). Did the authors determine the amount of water loss? There are no data. Furthermore, is it possible that there are mechanical reasons for the damage? What is the relevance of this observation for guttation?

Page 11, line 283-288: These sentences should be improved.

 Page 11, lines 292 -294: It is not clear what it is meant here. Obviously, this is about barley?

Page 11,  chapter 4.2: Here, the findings about the substances in the guttation liquid could be a little bit more discussed.

Page 11, line 312: As a general citation for long-distance transport in the xylem, the classic text of Tyree and Zimmermann (2013) is suggested (Tyree, M. T., & Zimmermann, M. H. (2013). Xylem structure and the ascent of sap. Springer Science & Business Media).

A general comment: “Spit water“ is – as far as I know – not used to describe guttation liquid.

 

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

The article deals with an interesting subject and uses pertinent experiments and analysis. However, some descriptions are lacking and need to be revised.

1-Throughout the text the authors use different names to refer to the parts of the bamboo leaf. For example: “Figure 5. Transverse section of the bamboo sheath and bamboo leaf”. Doesn't the bamboo leaf refer to the leaf as a whole, including the sheath and the leaf lamina? Is this sheath mentioned in fig 5 the culm sheath? Standardize the terms

2- “The vascular bundles at the bottom of the bamboo shoot were relatively well developed, and their cell structure was clear but lacked a nucleus (Figure 4E). Many nuclei of vascular bundle cells and parenchyma cells were observed around the upper part of the bamboo shoot, where the cells were smaller”

                2a. The authors need to insert the information of the analyzed region of the stem in the methodology and in the legend of figure 4.

 

2b. The differences observed between the vascular bundles of the apical and basal region refer to the degree of differentiation of the tissues. Clearly in figure 4G the tissues are still differentiating and for this reason the nuclei are evident. In this image it is possible to observe the vessel elements of the metaxylem still expanding and with cellular content. In image 4E the tissues are differentiated and the MX is expanded and functional, the fibers are differentiated and the cell wall is thick. Improve this description in the text, as it gives the wrong impression of "lacked a nucleus".

 

2c. Where metaphloem was indicated, the more correct would be just phloem. Because this is a complex tissue composed of many cell types and at this magnification it is not possible to indicate with certainty which cell is actually a metaphloem conducting cell.

2d. Image 4F does not bring any relevant information and could be removed, facilitating the construction of the figure with 6 images

 

3- “When compared with the vascular bundles of bamboo shoots, the sheath blades also included phloem, xylem vessel, and thickened posterior wall cells; however, there was no fibrous cap present”. Please review this description. The bundles in both regions have the same tissues. Do not use only "xylem vessel" the xylem in the vascular bundle is also a complex tissue and composed of xylem vessel (metaxylema and protoxylema in the primary xylem), parenchyma cells and fibers. In relation to the fibers, the difference between the bundles is that in the sheath the fibers are turned and concentrated towards the epidermis.

 

4- In figure 5 the images are with very low magnification, wrong position and it is not possible to see the details like "the vascular bundle sheath cells consisted of two layers". The magnification should be similar to the one from this work below and with the correct position (adaxial side facing up):

 

Anatomical characterization of the roots, leaves and culms of Guadua weberbaueri in different growing environments: file:///C:/Users/Juliana/Downloads/9366-Article%20Text-39728-1-10-20200630.pdf

5- “The outer sheath was composed of parenchyma cells, some of which were swollen, while the inner sheath was composed of thick-walled cells (Figure 5A). Both the fingerlike arm cells and irregular arm cells in bamboo leaf were not observed in the sheath blade (Figure 5A, B). ”

This description is wrong, please research the works below to improve your text

Vieira RC, Gomes DMS, Sarahyba LS, Arruda RCO. Leaf anatomy of three herbaceous bamboo species. Braz. J. Biol. 2002;62:907–922. doi: 10.1590/S1519-69842002000500021.

Shuguang Wang. Bamboo sheath—A modified branch based on the anatomical observations. Sci Rep. 2017; 7: 16132. Published online 2017 Nov 23. doi: 10.1038/s41598-017-16470-7

Carolin RC, Jacobs SWL, Vesk M. The structure of the cells of the mesophyll and parenchymatous bundle sheath of the Gramineae. Bot. J. Linn. Soc. 1973;66:259–275. doi: 10.1111/j.1095-8339.1973.tb02174.x

Shields LM. The involution mechanism in leaves of certain xeric grasses. Phytomorphology. 1951;1:225–251

 

6- It was not clear whether the authors found in the analyzed species hydatodes or at least modified stomata .

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The manuscript was substantially improved by the authors. There are some minor comments, mostly language, marked in the annotated pdf.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript was thoroughly revised. The authors accepted all the recommendations and actually made the changes. There are no details that should be revised.

Author Response

Dear reviewers,
       Thank you for all your hard work and recognition of our work.
Kind regards,
Prof. Gao