Effects of Light Intensity and Water Stress on Growth, Photosynthetic Characteristics and Plant Survival of Cistus heterophyllus Desf. Subsp. carthaginensis (Pau) M. B. Crespo & Mateo
, María Jesús Sánchez-Blanco 1,*, Beatriz Lorente 1, María José Vicente-Colomer 2 and María Fernanda Ortuño 1
Round 1
Reviewer 1 Report
In the present manuscript “Effects of light intensity and water stress on growth, photosynthetic characteristics and plant survival of Cistus het-erophyllus authors have identified the physiological mechanisms used by Cistus heterophyllus to cope with two typical abiotic conditions: water deficit and solar radiation in ex situ conditions; and determined the most limiting factor that compromises its development.
The abstract section is missing the experimental details, authors must add the treatment details in this section.
The abstract section is also written in a very descriptive form and authors must add some numerical values in the abstract section.
Line 16-17: Please delete lines 16-17 from the abstract section.
The introduction section should be written in a state of the art of form. It should start with the problem statement, then the effect of light intensity and water stress on plant growth and other characteristics, and then the solution. After that, they should add hypotheses and strong objectives.
Line 188: Please correct the symbol of degree centigrade.
Line 191: sub-script with numbers given in the formula of acids.
Line 210-212: It is better to add these lines in the materials and methods section.
Figure 2: In Figure to there is no vertical bar, authors should make this figure again.
The vertical bars should contain ± SE.
Similarly, figures 3, and 4 and all other figures given in the manuscript need correction.
The results section is poorly written and it must showcase some numerical values along with % increase or decrease rather than the simple statements.
The discussion section needs significant improvement with logical reasoning. It is enriched with results and it should be avoided in the revised version.
Thanks!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Minor changes are needed.
Author Response
In the present manuscript “Effects of light intensity and water stress on growth, photosynthetic characteristics and plant survival of Cistus heterophyllus authors have identified the physiological mechanisms used by Cistus heterophyllus to cope with two typical abiotic conditions: water deficit and solar radiation in ex situ conditions; and determined the most limiting factor that compromises its development.
The abstract section is missing the experimental details, authors must add the treatment details in this section.
Details about experimental design and treatments have been added.
The abstract section is also written in a very descriptive form and authors must add some numerical values in the abstract section.
Some results have been added with numerical values and percentages for its better understanding.
Line 16-17: Please delete lines 16-17 from the abstract section.
This line has been deleted.
The introduction section should be written in a state of the art of form. It should start with the problem statement, then the effect of light intensity and water stress on plant growth and other characteristics, and then the solution. After that, they should add hypotheses and strong objectives.
The introduction has been improved considering the comments of the reviewer.
Line 188: Please correct the symbol of degree centigrade.
The symbol has been corrected.
Line 191: sub-script with numbers given in the formula of acids.
Numbers have been corrected.
Line 210-212: It is better to add these lines in the materials and methods section.
As the reviewer suggested, this paragraph has been added to the material and methods section.
Figure 2: In Figure to there is no vertical bar, authors should make this figure again.
The vertical bars should contain ± SE.
Similarly, figures 3, and 4 and all other figures given in the manuscript need correction.
There has been a problem when the manuscript was submitted in PDF version, and figures could not be seen properly. This problem has been corrected and now bars and standard errors can be seen.
The results section is poorly written and it must showcase some numerical values along with % increase or decrease rather than the simple statements.
Numerical values and percentages have been added along to the description of results, for a better understanding.
The discussion section needs significant improvement with logical reasoning. It is enriched with results and it should be avoided in the revised version.
Taking into account the opinion of the rest of the reviewers, we think that discussion has a logical reasoning, since the results have been discussed and supported by other similar studies and related to each other. Results were only briefly described before discussion to place the reader, although, following the suggestions of the reviewer, results have been deleted as much as possible.
Reviewer 2 Report
In the present manuscript, the physiological mechanisms used by Cistus heterophyllus to cope with water deficit and solar radiation are presented.
Line 121: correct to "transplantation".
Lines 121-125: Provide the specifications of the shade mesh.
Figure 1: how rainfall or ETo are indicated in the figure? There are only two lines which refer to shade and open air conditions.
Revise the codes of treatments, e.g SUN-T1, SUN, T2, SUN-T3, SHADE-T1, SHADE-T2, SHADE-T3).
Line 147: add the names of the authors [19].
How the water treatments were scheduled? Did the authors measured physicochemical properties (water holding capacity, bulk density etc.) of the growth substrate? Did tha authors applied the amounts of water presented in Table 1 to both solar radiation treatments? Did plants of the shade treatment received any rainfall? Since, the conditions between shade and sun treatments differed, ETo also differed meaning that water requirements were not the same. So, the authors have to justify whether they aimed to subject plants to specific water stress conditions or to apply specific amounts of water. By measuring leaf water potential you can not regulate water stress conditions and manage irrigation.
Replace Figures 2, 3, 5 with Tables with actual data (mean values+/- SD). As it is, there is no indication of the treatment where each point refers to. It seems that the bars are not visible in Figures 5 and 6.
Revise the statistics in Table 2, based on the significance of the effect of the tested factors (main effects and their interaction). When there is no interaction, only the mean effects should be presented (e.g., in all the minerals except for S).
Table 3: why the rates of survived and damaged plants do not add up to 100%?
Author Response
Review 2
Line 121: correct to "transplantation".
It has been corrected
Lines 121-125: Provide the specifications of the shade mesh.
A wider description of the shade mesh has been added.
Figure 1: how rainfall or ETo are indicated in the figure? There are only two lines which refer to shade and open air conditions.
There has been a problem when the manuscript was submitted in PDF version, and figures could not be seen properly. Now rainfall and ETo can be seen.
Revise the codes of treatments, e.g SUN-T1, SUN, T2, SUN-T3, SHADE-T1, SHADE-T2, SHADE-T3.
Name of treatments has been revised and corrected.
Line 147: add the names of the authors [19].
Names of authors have been added.
How the water treatments were scheduled? Did the authors measured physicochemical properties (water holding capacity, bulk density etc.) of the growth substrate? Did the authors applied the amounts of water presented in Table 1 to both solar radiation treatments? Did plants of the shade treatment received any rainfall? Since, the conditions between shade and sun treatments differed, ETo also differed meaning that water requirements were not the same. So, the authors have to justify whether they aimed to subject plants to specific water stress conditions or to apply specific amounts of water. By measuring leaf water potential you can not regulate water stress conditions and manage irrigation.
Yes, we have data of the water holding capacity of substrates from T1. The quantity of water presented in Table 1 was the same in shade and sun conditions in order to see the effect of radiation in plants irrigated with the same amount of water. As shown in Figure 1, ETo inside the shading mesh was lower than in the open air. There were some precipitation episodes, which were received by plants in shade conditions, since the shading mesh was not opaque, although in a slightly more regulated way. We applied three irrigation levels, considering T1, the control, since these plants were irrigated until reaching the field capacity of the substrate. To calculate the maximum field capacity of the substrate, several pots were taken covered and immersed in water overnight. Later, the pots were removed and left until the drainage was insignificant. Then, the weight was taken on a scale. We followed the method described by Álvarez and Sánchez-Blanco (2013) for more information. Then, we stablished two more irrigation levels that we considered as a two deficit irrigation levels, since T2 and T3 were irrigated at 60% and 30% of the amount of water supplied in the control treatment (T1), respectively. Therefore, our objective was to submit plants to different irrigation regimens and evaluate their physiological behaviour. Then, during the experiment, we found a reduction of leaf water potential and gas exchange, as well as the increase of leaf temperature in plants irrigated with T2 and especially T3 treatment, which means that plants suffered water stress.
Replace Figures 2, 3, 5 with Tables with actual data (mean values+/- SD). As it is, there is no indication of the treatment where each point refers to. It seems that the bars are not visible in Figures 5 and 6.
Taking into account all the reviewers suggestions, figures in PDF version could not be seen properly, but this problem has been corrected and all details of figures can now be seen.
Revise the statistics in Table 2, based on the significance of the effect of the tested factors (main effects and their interaction). When there is no interaction, only the mean effects should be presented (e.g., in all the minerals except for S). We are not clear what the reviewer means. We think that what the reviewer means is to make a two-way ANOVA analysis, which we have done, but if the reviewer considers that we need to modify the table in another way, please let us know.
Table 3: why the rates of survived and damaged plants do not add up to 100%?
Survival rate shows the percentage of plants alive at the end of the experiment. From this percentage of plants alive, there is a percentage of plants that had visual damage (dry shoots and/or dry leaves). For instance, in the case of SUN-T1, 96,55% of plants survived (therefore 3,45% died) and the 18,97% of those alive plants showed visual damage.
Author Response File: 
Author Response.doc
Reviewer 3 Report
The MS "Effects of light intensity and water stress on growth, photosynthetic characteristics and plant survival of Cistus heterophyllus" presents the results of the studies of Cistus heterophyllus, an endemic plant of Murcia region. The authors tried to find out what conditions are to be used for growinging plants for recovery and conservation purposes. A lot of parameters were measured in the experiments with 2 irradiation levels and 3 oprions of water supply.
The main concern is that conclusions made do not follow from the results obtained. The Table 3 shows that survival rate of plants in SUN treatments is higher or similar, and the percentage of damafed plants is lower or similar to plants in SHADE treatmentg. But the conclusion made is that conditions used in SHADE treatments are optimum for growing plants. The second question is - Can the age of plants may affect the results of such experiments? Plants of what age were used in the experiments and what plants are used for recovedry or conservation programs?
Some technical problem occurs with figures. They are not visible.
Minor concerns:
- ex situ (lines 15, 95, 99, 430) should be italicazed.
- throughout the text: chl a, b should be italicazed.
- Line 139 - why only T1?
Line 424: the synthesis of chlorophyll (not chlorophyll content)
How do you know that the increase in chl content was due to enhanced synthesis, but not due to retarded chl degradation?
Author Response
Reviewer 3
The MS "Effects of light intensity and water stress on growth, photosynthetic characteristics and plant survival of Cistus heterophyllus" presents the results of the studies of Cistus heterophyllus, an endemic plant of Murcia region. The authors tried to find out what conditions are to be used for growing plants for recovery and conservation purposes. A lot of parameters were measured in the experiments with 2 irradiation levels and 3 options of water supply.
The main concern is that conclusions made do not follow from the results obtained. The Table 3 shows that survival rate of plants in SUN treatments is higher or similar, and the percentage of damaged plants is lower or similar to plants in SHADE treatment. But the conclusion made is that conditions used in SHADE treatments are optimum for growing plants.
We think that our conclusions are supported by results. Plants growing in shade conditions showed a better photosynthetic performance at the end of the experiment, higher chlorophyll content, which was linked to greener leaves, and a higher content of some nutrients such as K, P and Zn, compared to plants under sunny conditions. Aerial biomass seemed to be also higher in these plants but heterogeneity in the values prevented to see statistical differences. We highlight the treatment SHADE-T2 because those plants showed a high survival rate (similar to SUN-T1 and SUN-T2) but also the lowest percentage of damage plants.
The second question is - Can the age of plants may affect the results of such experiments? Plants of what age were used in the experiments and what plants are used for recovedry or conservation programs? All our plants were adult plants with similar age and obtained from a tree nursery, growing in the same crop and irrigation conditions. Therefore, we cannot affirm that the age may affect in this study. Most of the recovery and conservation programs have been focused in the germination of plants but this research arose because many of the plants growing in the forest nursery did not survive during the summer season.
Some technical problem occurs with figures. They are not visible.
There was a problem with figures in PDF version but it has been corrected.
Minor concerns:
- ex situ (lines 15, 95, 99, 430) should be italicazed.
It has been corrected.
- throughout the text: chl a, b should be italicazed.
It has been corrected.
- Line 139 - why only T1? The irrigation in the treatment T1 was made maintaining substrate moisture close to container capacity and we considered T1 as a control treatment. Then, we stablished that T2 was irrigated at 60% of the amount of water supplied in the control treatment, while T3 was irrigated at 30% of the amount of water supplied also in the control treatment.
Line 424: the synthesis of chlorophyll (not chlorophyll content) it has been changed.
How do you know that the increase in chl content was due to enhanced synthesis, but not due to retarded chl degradation?
We only indicate that, during the time studied, chlorophyll synthesis is induced in plants under shade compared to plants under sun, simply because we observed more chlorophyll content in these plants. Therefore, there was a greater synthesis in shaded plants. We believe that because this was a consequence of the lower radiation since this occurs in all shaded plants, regardless the irrigation level applied. It is not that there is a delay in degradation over time, which may be possible, but that there was more chlorophyll in shaded plants than in sunny plants.
Author Response File: Author Response.doc
Round 2
Reviewer 1 Report
Still, figures have the same problem. I suggest the authors to use some latest software to make these figures and remove this problem in the final version.
Minor changes are needed.
Author Response
Dear Reviewer 1
Thans for your comments. The authors have used a latest software to make the figures.
Reviewer 2 Report
The authors have answered most of my comments. However, there are some issues that have to be addressed before the manuscript can be accepted for publication.
Still it is not clear how water treatments were scheduled. If I understood well, in their response to my previous comment the authors mentioned that they used T1 as the control treatment (100% of field capaciy) and also applied two stress levels: T2 (60% of field capacity) and T3 (30% of field capacity). Then in Figure 1 we can see there is a difference in ETo and rainfall between open-air and shade conditions. Therefore, if they applied the same amounts of water to treatments T2 and T3 under sahde and open-air, the aimed stress levels cannot be achieved.
The problem with the Figures still remains.
In Table 2, the Latin letters should be used only when a significant effect of the main factors and/or their interaction is detected. For example, in the case of Na there are no significant effects and the authors use Latin letters; or in P the interaction is not significant and the authors use Latin letters.
Author Response
Dear Reviewer 2
-Thank you for your comment. We agree with your approach, however, and according to the leaf water potential values ((Fig. 2A), we can see similar values in both radiation conditions as we comment in the text “leaf water potential decreased in plants subjected to deficit irrigation and in both radiation conditions, plants from treatments SUN-T3 and SHADE-T3 showing the lowest values at the end of the experiment (-1.57 MPa and -1.62 MPa, respectively)”, in spite of ETo was lower in shade than in open-air (Figure 1). Therefore we think that stress levels could be achieved.
- Table 2 has been mofified according to the comment.
Reviewer 3 Report
The questions are answered and editing is made.
Author Response
Dear Reviewer 3
Thanks for your comments.
