Light Regimes Regulate Leaf and Twigs Traits of Camellia oleifera (Abel) in Pinus massoniana Plantation Understory

Round 1

Reviewer 1 Report

Zhang et al’s paper investigated a lot of leaf and twig traits in relation to the adaptation strategy of Camellia oleifera to different light regimes in the understory of Pinus massoniana plantation. The authors measured diverse traits, which clearly shows distinct strategy to adapt different light regimes in the understory of P. massoniana. I believe that the authors’ results provide important information for the cultivation of C. oleifera in the Pinus massoniana forests.

 

Although the data set is very good, there are a lot of uncertainties and discrepancies in the discussion part. I recommend substantial and thorough revision in the discussion, and in the abstract part. 

 

Followings are the specific comments.

 

Major

 

1.     Line 472-473. This sentence is wrong because leaf photosynthesis rate (area-based) does not directly relate to leaf size. This part also contradicts to the obtained result. Please check the data and the reference carefully.

2.     Line 477. Again, this explanation is inappropriate because photosynthesis was decreased under low light regimes. 

3.     Line 478 – 479. I do not think that increase in LA under low light is a photoprotection strategy. Photoprotection strategy is decreasing LA to reduce excess light energy captured by the leaf.

4.     Line 481-482 Increase the proportion of leaf biomass to what?

5.     Line 483 – 484. I do not think that high leaf water content involves high leaf photosynthesis.

6.     Line 493. Under sufficient light, LT (leaf thickness) may be increased, not decreased. Please check the reference.

7.     Line 504- 505. I do not agree this, because under the very high light (CK), the LSP was not increased compared to high light (HL, Table 4).

8.     Line 508 – 509. High AQY does not necessarily shows adaptability to low light. More careful discussion is needed.

9.     Line 515 – 520. I do not understand this part. How does the decrease in stomatal density increase photosynthetic area? Stomata locates at the lower side of the leaves, and a major part of the photosynthetic tissue locates at the upper side of the leaves. 

10.   Line 526. I recommend deleting this sentence.

11.   Line 530. Is there any reference support this sentence?

12.   Line 545. How does high TC content relate to the nutrient utilization strategy?  

13.   Line 584 and 587. The sentence is doubled.

14.   Line 580 – 597. This part is complicated. I recommend being shorten this part.

15.   Line 610. What is the meaning of plant distribution?

 

Others

 

1.     Line 44. “light is for” => “light for”

2.     Line 46. Delete “Thus”.

3.     Line 56 – 57. What is the meaning of “C. oleifera individuals undergo over vegetative growth”?

4.     Line 57. Please add “ and therefore “ before “fruit dropping”.

5.     What is the meaning of “the lower leaf area and photosynthesis rate of Sinopodophyllum hexandrum were lesser under strong light”?

6.     Line 75. Please delete “that”.

7.     Line 78. Add “light regimes” before “led”.

8.     Line 80. Delete “special”.

9.     Line 86 – 85. Here shows only four categories.

10.  Line 91 – 92. “ … total chlorophyll content decreased with the decrease of light intensity” => “ …total chlorophyll content decreased with the increase of light intensity”. Please check the reference.

11.  Line 92 – 94. “The leaves and mesophyll cells of plants become thicker, the palisade tissue becomes longer, and the sponge tissue increases”. Please check the expression in the reference carefully. Under strong light, more developed mesophyll cells with thick palisade tissue are often observed.

12.  Line 94 – 101. This part is not clear. How does the twig size relate to the light regime?

13.  Line 142- 144. How long did the authors monitor the light regimes of the study sites? Where and how did the authors set the light sensor? How many trees in each study site, and how about the distance between trees? How about the area of each study site?

14.  Lines 156, 167, and 222. What is the meaning of “functional leaves”?

15.  Line 180 – 181. How many leaves did the authors use for the leaf anatomical observation for each study site?

16.  Line 183. What is “style table”?

17.  Line 184. electron => optical

18.  Line 185. What is the meaning of temporary slice?

19.  Line 190. How many leaves did the authors use for the chlorophyll quantification for each study site?

20.  Line 234. Please add “ · ” between alpha and PAR. Use lowercase for “max” of “Pmax”.

21.  Line 244. How did the authors classify the fruit?

22.  Table 1. Please align the number of significant digits.

23.  Line 353. Please add explanation for the abbreviations such as TC, TN and TP.

24.  Figure 6. I recommend showing the data in a table.

25.  Figure 7. Please show error bars for each data point.

 

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

This is generally an experimentally solid paper addressing an issue of significance, especially under current economic conditions, and it would therefore be expedient to publish this work quickly.  The authors have addressed an understudied topic and used reliable and well-proven techniques to address their points.  However, there are a few issues which should be addressed first:

 

In the abstract, the term "ML" is introduced without explanation.

Lines 54-56: "However, with the gradual development of P. massoniana individuals, the intensity and duration of sunlight plantations in the plantation understory are gradually decrease, which remarkably influences C. oleifera growth." - Is this referring to availability of sunlight in the understory?

Lines 67-69: "Guo et al [11] found that the lower leaf area and photosynthesis rate of Sinopodophyllum hexandrum were lesser under strong light, and greater in medium light regime." - is the leaf area greater or lesser?  Unclear.

In 2.1, the light intensities are given as averages, but the cause of these intensities is not clear- you can get a moderate average from having general shading all day, intermittent shading throughout the day, or total shading for part of the day and no shading for part of the day.  These would, however, promote very different growth strategies.  Can this be expanded to explain why the light levels were decreased at lower-light sites?

Line 168: "A leaf was cut into cut a 4 mm" - what does this mean?

Line 185: The Leica DM2500 is not an electron microscope.

Table 1: Considering the deviations, some of these statistical significance groupings look a bit strange, for example groups a and b in leaf area, in which both appear to be solidly within the margin of error of each other.  This is also present, though less noticeably, in Table 2, and very noticeably in the Pmax in Table 4 and in Table 5 in general.

Figure 5: It may be useful to line-break the Y axis in panel A to make the difference between the four conditions clearer by expansion.

Line 512: "The stomata of C. oleifera leaves are located on the back of the leaves" - What is meant here is not clear.

Why are TN and TP higher under high light?  This stands out and is not really clear from the discussion.

Considering the introduction's comparison with other species, it is strange that there is no such comparison in the discussion.

General English editing is necessary.  The quality is fine in some sections and in others what's written is completely unclear.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Zhang et al’s paper improved by the revision. However, there remains a lot of uncertainties in the MS. Please take enough time to check the data and discussion carefully.

 

1.     Line 256. The explanation for alpha, PAR and Pn are missing.

2.     Table 1. The units for LL, LW, LA, LC, LT and SLA seem to be wrong. Please correct them.

3.     Line 504 – 505. LW did not increase with the decrease in light regime.

4.     Line 508 – 512. These explanations seem to be wrong. The references are not related to the sentences in the MS. Please check the MS carefully, referring appropriate references. 

5.     Line 512 - 513. Leaf biomass (LB) is constant across the light regimes (Table 1).

6.     Line 516. LS in HL was not higher than those in ML and LL statistically.

7.     Line 525. Add “overall” after “decreased”.

Author Response

Please see the attachment.

Author Response File: Author Response.docx