Phosphorus Nutrition and Water Relations of European Beech (Fagus sylvatica L.) Saplings Are Determined by Plant Origin
, Sanja Bogunović 1, Aikaterini Dounavi 2, Florian Netzer 3, Monika Eiblmeier 3, Michael Dannenmann 4, Stephanie Rehschuh 4, Heinz Rennenberg 3,5 and Mladen Ivanković 1,*Round 1
Reviewer 1 Report
Reviewer: The manuscript titled "Phosphorus nutrition and water relations of European beech (Fagus sylvatica L.) saplings are determined by plant origin" elucidated the physiological response of Croatian beech saplings originating from 10 natural forest stands to experimentally applied water deprivation. The authors done a well conducted research with mainly focusing on the effect of external factors such as soil nitrogen and phosphorus availability control the response of beech saplings. Of course, the authors collected beech samplings from 10 forest stands with differed in soil type, chemical soil properties as well as climate and then observed for the antioxidative system in leaves and fine roots under drought condition, which took a long time with lots of work. These results provided a reference for the choice of beech ecotypes for the drought adaption.
The sensitive of the categorization of saplings to water deprivation is related to genetic parameters. What's the distribution and the percentage of 10 natural forest on beech ? The research significance is unclear. In fact, it is not difficult to investigate the death rate or influence of drought on beech in field. Overall, it is relatively illogical without a deep impression and discussion part is not in-depth.
Specific comments:
Line 24-25 Abstract part: Research background is too long to understand the research information and results. e.g. abstract part should list experiment time and so on.
Line 39-40 The part suggests supplement research significance.
Line 125-132 2.1 Experimental design and plant material part. It is unclear what degree of water deprivation was and how to control soil moisture ? What is the relationship between air humidity and soil moisture ? I suggest that you should clarify the soil moisture instead of air humidity.
Line 143-145 The absolute and the relative amount of the height of saplings was negative value according to your formula, please check whether it is in conformity with the routine.
Line 143-144 There are many printer’s errors in whole manuscript, e.g. line 148-149, δ13C; line 509, habitat; line 550 and 553, correlation.
Comments for author File: 
Comments.docx
Author Response
Dear reviewer 1,
Thank you for reviewing our manuscript. We tried our best to improve the manuscripts according to your comments. We accepted all your comments.
Reviewer 1:
Specific comments:
Line 24-25 Abstract part: Research background is too long to understand the research information and results. e.g. abstract part should list experiment time and so on.
Answer 1
The abstract was corrected:
Abstract: Climate change, specifically the increasing frequency and intensity of summer heat and drought, has severe influences on the performance of beech forests, including declining growth, reduced nutrient turnover, enhanced mortality, and a shift of its spatial distribution northwards and towards higher elevation. The present study aimed to characterize the physiological response of Croatian beech saplings originating from 10 natural forest stands to experimentally applied water deprivation in a common garden experiment. It was aimed to evaluate to what extent external factors such as climate as well as nitrogen (N) and phosphorus (P) availability in the soil of the natural habitats control the response of beech saplings to water deprivation. For this purpose, beech saplings from 10 forest stands that differed in soil type, chemical soil properties, as well as climate were collected in winter, cultivated in an artificial soil substrate under controlled conditions for one year, and then subjected to 29 days of water deprivation. Responses to water deprivation were observed in the antioxidative system (total ascorbate, reduced ascorbate, oxidized ascorbate, and redox state) in leaves and fine roots. The latter allowed us to categorize saplings as adapted or sensitive to water deprivation. P over N availability in the soil rather than climatic conditions in the natural habitats controlled the response of beech saplings to the water deprivation event. The categorization of saplings as adapted or sensitive to water deprivation was related to genetic parameters. The results of this multidisciplinary study (tree physiology, climate data, and genetic data) are considered to be highly significant and beneficial for the adaptation of European beech forest to changing climate conditions.
Line 39-40 The part suggests supplement research significance.
Answer 2
The statement concerning research significance was added in the Abstract:
The results of this multidisciplinary study (tree physiology, climate data, and genetic data) are considered to be highly significant and beneficial for the adaptation of European beech forest to changing climate conditions.
Line 125-132 2.1 Experimental design and plant material part. It is unclear what degree of water deprivation was and how to control soil moisture ? What is the relationship between air humidity and soil moisture ? I suggest that you should clarify the soil moisture instead of air humidity.
Answer 3
According to Leuschner and Lendzion (2009) high air humidity and ample soil moisture are key abiotic factors in beech forests on calcareous soils. The relationship between air humidity and soil moisture is reported in Lakhal and Ayyoub (2015). The authors noted that the experimental results indicate that soil moisture content in the upper soil layer fluctuates in the same manner as the diurnal fluctuation of relative air humidity. Unfortunately, we did not measure soil moisture in the present study.
Line 143-145 The absolute and the relative amount of the height of saplings was negative value according to your formula, please check whether it is in conformity with the routine.
Answer 4
The formula was not written correctly. We corrected: (the height at the end of the experiment [cm] – the height at the start of the experiment [cm])/height at the start of the experiment [cm])*100)
Line 143-144 There are many printer’s errors in whole manuscript, e.g. line 148-149, δ13C; line 509, habitat; line 550 and 553, correlation.
Answer 5
All the printer’s errors have been corrected in the text.
Author Response File: Author Response.docx
Reviewer 2 Report
Phosphorus nutrition and water relations of European beech (Fagus sylvatica L.) saplings are determined by plant origin
Dear authors, congratulations on the quality work. The paper is interesting, relevant, and well designed. However, it is necessary to make some corrections throughout the text to improve the quality of the presentation
In Introduction section
Please add some previous relevant studies and results, and add some history and background of the Croatian forestry, drought condition in this region.
Line No. 47. Add some ecological and economical importance of this species (Fagus sylvatica L) in this paragraph.
Line No. 109. Is single tree progeny? please mention in the text.
Line No. 116. Please add the soil properties using in the pots during the experiment.
Line No. 128. Please add the intensity of the solar radiation.
Line No. 137. Please correct the sentence.
Line No. 150. Please correct the reference according to the format of journal.
Line No. 202. Please correct the reference according to the format of journal
Line No. 233. Please add the reference in this section.
Line No. 333. According to my point of view if you add the P value at the end of the table it should be better.
Material and Method Section.
No need to change in this section.
Results and Discussion
No need to change in this section.
Author Response
Dear reviewer 2,
Thank you for reviewing our manuscript. We tried our best to improve the manuscripts according to your comments. We accepted all comments except the one suggestion: Line No. 333. According to my point of view, if you add the P value at the end of the table, it should be better. For that, we gave our explanation.
Reviewer 2:
In Introduction section
Please add some previous relevant studies and results, and add some history and background of the Croatian forestry, drought condition in this region.
Answer 1
We added the relevant data in Introduction:
According to Glavač [8] in the microhabitats under the beech canopy, the supply of water and minerals from the leaves is more favorable. With the increase of industrialization in the middle of the 20th century, favorable microlocations disappeared due to atmospheric pollution. The same author stated that beech forest damage caused by atmospheric pollution is manifested as a direct impact on leaves and assimilation, the introduction of the substances into the soil via dry and wet deposition, and their influence on physiological processes. These factors cause indirect damage by climate change and increase the susceptibility of trees to extreme climatic, edaphic, and biotic conditions. Previous studies of Croatian beech provenances accomplished its genetic variation and adaptation to changes in its climate environment [9-15]
Line No. 47. Add some ecological and economical importance of this species (Fagus sylvatica L) in this paragraph.
Answer 2
The ecological and economical importance of this species was described:
The ecological relevance of beech is substantial because of its broad ecological range, including its ability to clean the air, filter water supplies, manage erosion and floods, maintain biodiversity, and conserve genetic resources. It is utilized as wood-processing material, firewood, and charcoal because of the high quality of the wood [6].
Line No. 109. Is single tree progeny? please mention in the text.
Answer 3
We corrected the sentence as follows: At each forest site, 5 trees (minimal distance 50 m) were selected. Two to three-year-old beech saplings under the selected trees were dug out of the soil without destroying the root system during the winters of 2014 and 2015.
Line No. 116. Please add the soil properties using in the pots during the experiment.
Answer 4
The soil properties are added in the text:
(organic content 60%; salt in g/L KCl – 1, N in mg/L CaCl2 - 140, P2O5 in mg/L CAL – 160, K2O in mg/L CAL – 180, Mg in mg/L CaCl2 - 100, S in mg/L CaCl2, pH 5.8; light peat 0-40 mm – 70%, black peat 0-40 mm – 30%; N-P-K – 14-16-18; Stender Spezialsubstrat MC 510, Stender AG, Schermbeck, Germany).
Line No. 128. Please add the intensity of the solar radiation.
Answer 5
We did not collect the data of the solar radiation, but we can describe it as follows: The intensity of solar radiation was below 300 W/m2, because at this value of solar radiation, shading was activated inside the greenhouse.
Line No. 137. Please correct the sentence.
Answer 6
The sentence is corrected: Fully expanded leaves and 1 g of the fine roots (diameter < 2 mm) per sapling were collected, pooled, frozen in liquid nitrogen, and stored at 80 °C until analyses.
Line No. 150. Please correct the reference according to the format of journal.
Answer 7
The reference is corrected.
Total C, N abundance and the δ13C signature were determined in the fine roots and leaves by EA-IRMS as described by Simon et al. [31].
Line No. 202. Please correct the reference according to the format of journal
Answer 8
The reference is corrected.
PCRs were performed using fluorescently labelled primers according to Dounavi et al. [20].
Line No. 233. Please add the reference in this section.
Answer 9
- Schlotter, D., Schack-Kirchner, H., Hildebrand, E.E., von Wilpert, K. Equivalence or complementarity of soil-solution ex-traction methods. J. Plant Nutr. Soil Sci. 2012, 175, 236–244. http://dx.doi.org/10.1002/jpln.201000399.
Line No. 333. According to my point of view if you add the P value at the end of the table it should be better.
Answer 10
Due to the transparency of the data in the table, in our opinion, writing P value at the end of the table would lead to confusion in the interpretation of the data with regard to different values of p.
Author Response File: Author Response.docx
