Individual and Interactive Effects of Elevated Ozone and Temperature on Plant Responses
Round 1
Reviewer 1 Report
The presented manuscript is a very interesting work, indicating many important issues and should be published. However, I suggest the authors pay attention to one important thing. The authors write generally about the plant's response to ozone and temperature. I think it would also be worth highlighting the type of plants observed. Plants from hot climates will react differently to ozone and temperature, for which the temperature of 30oC is normal, and differently to plants growing in the temperate zone. Therefore, one should not generalize and talk about plants in general.
Comments for author File: 
Comments.pdf
Author Response
Author's Reply to the Review Report
(Manuscript ID: horticulturae-1609127)
Title
Individual and Interactive Effects of Elevated Ozone and Temperature on Plant Responses
We are pleased to resubmit for publication the revised version of entitled “Individual and Interactive Effects of Elevated Ozone and Temperature on Plant Responses”. We would like to thank the reviewers and the associate editor for their precious time and invaluable comments. We are very much thankful to three reviewers for deep and thorough comments on an amended version of the manuscript. We have revised our manuscript according to their suggestions and comments of three anonymous reviewers. We have carefully addressed each of comments by three reviewers as outlined below. We hope that the reviewers and the editors will be satisfied with author's reply to the review report and the revised version.
Yours sincerely,
Review Report - Reviewer 1
Comments and Suggestions for Authors
The presented manuscript is a very interesting work, indicating many important issues and should be published. However, I suggest the authors pay attention to one important thing. The authors write generally about the plant's response to ozone and temperature. I think it would also be worth highlighting the type of plants observed. Plants from hot climates will react differently to ozone and temperature, for which the temperature of 30â—¦C is normal, and differently to plants growing in the temperate zone. Therefore, one should not generalize and talk about plants in general.
Reply: We are grateful for your precise and detailed comments. We have rewritten the sentence in ‘Biochemical changes in response to elevated temperatures’ section not to generalize it.
Line 214-215: Generally, the biochemical characteristics of plants are negatively affected by air temperatures above 5 °C than the optimum [55].
Reviewer 2 Report
Dear authors,
The manuscript aimed to review the effect of ozone and temperature, individually or together on plant response. This manuscript was clearly written with very good citations related to the topic.
There are only few comments related to the manuscript:
- This is a review article, therefore consider changing the title of the manuscript by deleting the "A review…". In my opinion it would be better to replace it.
Line 29: The word changes is repeated twice… It might be possible to delete the first one:
Anthropogenic activities, such as excessive fossil fuel use and frequent land-use changes, have led to changes in the Earth’s atmosphere.
Lines 37-41: please indicate the concentrations/levels of ozone in the atmosphere. What are the levels that it might reach (nL L-1)
Section 2: Plant responses to ozone. I could not find in the manuscript an information related to a possible acclimation of the plant to increase ozone levels. I think that it is necessary to relate to this possibility. I am sure that there are few articles related to this topic. For example:
Held, A.A., Mooney, H.A. and Gorham, J.N., 1991. Acclimation to ozone stress in radish: leaf demography and photosynthesis. New Phytologist, 118(3), pp.417-423.
Line 80 (and other similar citations) the beginning of the sentence is [22] studied… in my opinion you should add the researcher name as follow, but only if the editor think it is o.k.:
Wan et al., [22] studied visible symptoms indicating O3 injury on O3-sensitive trees and 80 shrubs around Beijing (Figure 2).
Line 140: please add in brackets: AsA-GSH cycle (glutathione-ascorbate cycle)
Line 289, Section 5: Consider rephrasing the sentence:
In this paper we summarized the plant responses to the combined and individual effects of…
Line 294: add to the sentence:
As demonstrated in Section 2, plant responses to ozone, tropospheric…
General comment: Does radiation has also an impact on plant responses together with ozone and temperature. Is there a place to mention its effect?
Comments for author File: Comments.pdf
Author Response
Author's Reply to the Review Report
(Manuscript ID: horticulturae-1609127)
Title
Individual and Interactive Effects of Elevated Ozone and Temperature on Plant Responses
We are pleased to resubmit for publication the revised version of entitled “Individual and Interactive Effects of Elevated Ozone and Temperature on Plant Responses”. We would like to thank the reviewers and the associate editor for their precious time and invaluable comments. We are very much thankful to three reviewers for deep and thorough comments on an amended version of the manuscript. We have revised our manuscript according to their suggestions and comments of three anonymous reviewers. We have carefully addressed each of comments by three reviewers as outlined below. We hope that the reviewers and the editors will be satisfied with author's reply to the review report and the revised version.
Yours sincerely,
Review Report - Reviewer 2
Comments and Suggestions for Authors
The manuscript aimed to review the effect of ozone and temperature, individually or together on plant response. This manuscript was clearly written with very good citations related to the topic.
There are only few comments related to the manuscript:
This is a review article, therefore consider changing the title of the manuscript by deleting the "A review…". In my opinion it would be better to replace it.
Reply: We are grateful for your precise and detailed comments. We have rewritten the title to shorten and clarify this research.
Line 2-3: Individual and Interactive Effects of Elevated Ozone and Temperature on Plant Responses
Line 29: The word changes is repeated twice… It might be possible to delete the first one:
Anthropogenic activities, such as excessive fossil fuel use and frequent land-use changes, have led to changes in the Earth’s atmosphere.
Reply: According to your suggestion, we have deleted above sentence you mentioned in ‘Introduction’ section
Line 27-29: Climate change, including global warming, has been occurring over the last several decades, and is now recognized as the most significant threat to human and ecosystem health [1].
Lines 37-41: please indicate the concentrations/levels of ozone in the atmosphere. What are the levels that it might reach (nL L-1)
Reply: According to your suggestion, we have added this sentence in ‘Introduction’ section to indicate the ozone concentrations in the atmosphere.
Line 39-41: Ambient O3 concentration have risen from less than 10 nL L-1 before the industrial revolution to midday summer concentration in many parts of the Northern Hemisphere exceeding 60 nL L-1 [5].
Section 2: Plant responses to ozone. I could not find in the manuscript an information related to a possible acclimation of the plant to increase ozone levels. I think that it is necessary to relate to this possibility. I am sure that there are few articles related to this topic. For example:
Held, A.A., Mooney, H.A. and Gorham, J.N., 1991. Acclimation to ozone stress in radish: leaf demography and photosynthesis. New Phytologist, 118(3), pp.417-423.
Reply: Thank you for pointing this out. We have added sentences in ‘Physiological changes in response to ozone’ section to add an information related to a possible acclimation of plants to elevated O3.
Line 129-131: Plants can enhance their O3 stress tolerance by regulating physiological mechanism such as stomatal closure and an increase of antioxidants. This acclimation mechanism enables stomata to remain partly open and facilitate photosynthesis-related gas exchange, avoiding drastic plant growth decreases [37,38].
Line 80 (and other similar citations) the beginning of the sentence is [22] studied… in my opinion you should add the researcher name as follow, but only if the editor think it is o.k.:
Wan et al., [22] studied visible symptoms indicating O3 injury on O3-sensitive trees and 80 shrubs around Beijing (Figure 2).
Reply: Based on your suggestion, we have rewritten these sentences in ‘Visible symptoms of sensitive plants to ozone’ section.
Line 81-84: Wan et al. [22] studied visible symptoms indicating O3 injury on O3-sensitive trees and shrubs around Beijing (Figure 2). Wilting occurred in Medicago truncatula under an O3 concentration of 70 nL L-1 and necrotic spots appeared on the leaves within 6 days [23]. Lee et al. [24] studied Brassica juncea L., which is widely cultivated in East Asia.
Line 140: please add in brackets: AsA-GSH cycle (glutathione-ascorbate cycle)
Reply: Thank you for pointing this out. We have rewritten the sentence in ‘Biochemical changes caused by ozone’ section.
Line 145-148: ROS concentrations are mitigated by enzymatic antioxidants such as those involved in the ascorbate-glutathione cycle (AsA-GSH cycle), which include catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), and glutathione reductase (GR) [45].
Line 289, Section 5: Consider rephrasing the sentence:
In this paper we summarized the plant responses to the combined and individual effects of…
Reply: We are grateful for your precise and detailed comments. We have rephrased the sentence in ‘Conclusion’ section.
Line 299-300: In this paper we summarized the plant responses to the combined and individual effects of elevated O3 and temperature, including physiological and biochemical changes.
Line 294: add to the sentence:
As demonstrated in Section 2, plant responses to ozone, tropospheric…
Reply: We are grateful for your detailed comments. We have added the sentence in ‘Conclusion’ section.
Line 304-305: As demonstrated in Section 2, plant responses to ozone, tropospheric O3 is a critical air pollutant with many negative consequences for plants.
General comment: Does radiation has also an impact on plant responses together with ozone and temperature. Is there a place to mention its effect?
Reply: We are grateful for this comment. As you mentioned, the considerable variety of plant responses to elevated O3 is most likely related to the interactive effects of other co-occurring environmental variables including not only temperature, but also solar radiation, drought, and increased NOx in the atmosphere. But we have focused on the interaction between elevated O3 and temperature since temperature is well known to be a strong parameter related to O3 concentration and plant growth. We have added this sentence in ‘Plant responses to ozone under elevated temperatures’ section to make it clear.
Line 260-264: Especially, the considerable variety of plant responses to elevated O3 is most likely related to the interactive effects of other co-occurring environmental variables including temperature, solar radiation, drought, and increased NOx in the atmosphere [80]. In this review, we focus on the plant response of the interactive effect of elevated temperature and O3.
Reviewer 3 Report
The review offers overview of current research on elevated ozone and temperature effects in plants. It is well written and explained. Some minor concerns are listed in the pdf document.
Comments for author File: Comments.pdf
Author Response
Author's Reply to the Review Report
(Manuscript ID: horticulturae-1609127)
Title
Individual and Interactive Effects of Elevated Ozone and Temperature on Plant Responses
We are pleased to resubmit for publication the revised version of entitled “Individual and Interactive Effects of Elevated Ozone and Temperature on Plant Responses”. We would like to thank the reviewers and the associate editor for their precious time and invaluable comments. We are very much thankful to three reviewers for deep and thorough comments on an amended version of the manuscript. We have revised our manuscript according to their suggestions and comments of three anonymous reviewers. We have carefully addressed each of comments by three reviewers as outlined below. We hope that the reviewers and the editors will be satisfied with author's reply to the review report and the revised version.
Yours sincerely,
Review Report - Reviewer 3
Comments and Suggestions for Authors
The review offers overview of current research on elevated ozone and temperature effects in plants. It is well written and explained. Some minor concerns are listed in the pdf document.
The lists in the pdf document
Line 84: Please verify.
Reply: Thank you for pointing this out. We have changed the sentence in ‘Visible symptoms of sensitive plants to ozone’ section.
Line 85-86: Under an O3 concentration of 100 nL L-1 in an O3 fumigated growth chamber, B. juncea L. displayed visible symptoms (bleaching) indicating O3 injury (Figure 3).
Line 94: Please check whether the leaf photos shown relate to treatment after 7 or 14 days?
Reply: Thank you for pointing this out. We have checked this photos shown related to treatment after 14 days and changed the sentence in ‘Visible symptoms of sensitive plants to ozone’ section.
Line 95: The visible symptoms of O3 damage under an O3 concentration of 100 nL L-1 at 14 days after exposure. Photos from Lee et al. [24].
Line 154: Please verify this reference
Reply: We are grateful for your comment. We have verified this reference again.
Line 157-160: Plant responses to O3 involve the regulation of guard cell ion channels. The accumulation of ROS in the extracellular space activates a still unknown calcium channel protein and increases cytosolic calcium accumulation, thus activating calcium-dependent protein kinases (CPKs) [49].
Line 156: Full name of the protein should be written in lowercase. Or please change all protein names in uppercase letters throughout the manuscript.
Reply: Based on your suggestion, we have rewritten full name of protein in these sentences in ‘Visible symptoms of sensitive plants to ozone’ section.
Line 160-169: Calcium is a second messenger that contributes to diverse signaling cascades that regulate plant stress responses. The activation of two types of anion channels, the slow anion channel 1 (SLAC1) and the quickly activating anion channel 1 (QUAC1), then causes stomatal closure [50,51]. ROS activate the protein kinase open stomata 1 (OST 1), which controls the outward rectifying SLAC1 and QUAC1 channels, as well as the inward rectifying K+ channel KAT1 [52,53]. OST1 activity is limited by ABA-insensitive 1 (ABI 1) and ABI 2 protein phosphatase 2Cs, which are inactivated by the abscisic acid receptor PYR/PYL. SLAC1 is also activated by CPKs and the ROS-induced guard cell hydrogen peroxide-resistant 1 (GHR1) protein [48] (Figure 6).
Line 171: Please verify the original article sourcing this figure.
Reply: Thank you for pointing this out. We have added the reference to inform the original article.
Line 172-177: Figure 5. Reactive oxygen species detoxification systems in plants under ozone stress conditions. APX: ascorbate peroxidase; AsA: ascorbate; CAT: catalase; DHAR: dehydroascorbate reductase; DHA: dehydroascorbate; GR: glutathione reductase; GSH: reduced glutathione; GSSG: oxidized glutathione; H2O2: hydrogen peroxide; MDHA: monodehydroascorbate; MDHAR: monodehydroascorbate reductase; O2- : superoxide anion; OH-: hydroxyl radical; SOD: superoxide dismutase. Adapted from Foyer and Halliwell [46].
Line 187: Please examine the cited manuscript.
Reply: We are grateful for your precise and detailed comments. We have removed the cited manuscript since the citation is not necessary in this manuscript.
Line 191-193: Constantly elevated temperatures also cause physiological changes in plants. The plant characteristic most susceptible to elevated temperatures is water status [57].
Line 208-209: Is this quoted properly?
Reply: Thank you for your precise comments. We have changed the sentence in ‘Biochemical changes in response to elevated temperatures’ section to make it clarify.
Line 214-215: Generally, the biochemical characteristics of plants are negatively affected by air temperatures above 5 °C than the optimum [55].
Line 210: Please check this citation.
Reply: We are grateful for your comment. We have checked this reference again.
Line 215-217: Elevated temperature stress may cause the excess production of reactive oxygen species (ROS), leading to oxidative stress [63].
Line 213: Please check this citation.
Reply: We are grateful for your comment. We have added citation to make it clear.
Line 217-220: ROS, including singlet oxygen (1O2), the superoxide radical (O2-), hydrogen peroxide (H2O2), and hydroxyl radicals (OH-), can cause lipid peroxidation, protein oxidation, changes in enzyme activities, and oxidative damage to membranes, all of which lead to cell death [63, 64].
Line 222: Misquoted literature.
Reply: We are grateful for pointing this out. We have changed correct citation (Savicka and Škute, 2010) in this sentence.
Line 227-228: In a study with wheat kept at 33 °C, oxidative stress significantly increased membrane peroxidation by 28%, greatly increasing solute leakage [68].
Line 257: Please verify.
Reply: We are grateful for your comment. We have checked this reference again.
Line 266-267: Furthermore, elevated temperatures may promote O3 accumulation by influencing sunny, dry, and stagnant atmospheres [81].
Line 271: Please verify.
Reply: We are grateful for your comment. We have added citation to make it clear.
Line 280-281: Increased temperatures above the optimum may decrease the uptake of ozone by reducing stomatal conductance [55,85].
Line 272: Verify citations - Does temperature elevation enhance ozone uptake?
Reply: We are grateful for your comment. We have changed correct citations to make it clear.
Line 281-285: However, due to increased stomatal conductance, moderately elevated temperatures (+5 °C) can enhance ozone uptake [24,86]. Several researches reported that +5 °C above an optimal temperature increased O3-induced foliar damage and reduced photosynthesis in chamber experiments with constant humidity [24,86].
Line 285: Verify citation, is stomatal response in relation to O3 flux
Reply: Thank you for pointing this out. We have added the citation to inform of the relation to O3 flux and stomatal opening under higher ambient temperature.
Line 294-296: Without confounding changes in humidity, the stomatal response to higher ambient temperatures obviously showed increased stomatal opening in relation to O3 flux [93,94].
