Dynamics of Enzyme Activities during the Decomposition of Castanopsis carlesii Leaf Litter in the Forest Canopy and Forest Floor in a Mid-Subtropical Area

Round 1

Reviewer 1 Report

The design of the experiment and its relevance from ecological point of view is totally unclear.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

It is a very interesting article containing both new experimental data on exymes’ activity and the use of indicators of ecoenzymatic stoichiometry for the evaluation of C, N and P limitations of microbial growth in forest litter fall. The MS is well structured and all positions are well proved. 

Title. 1)“…phosphorus availability…”  in the article, you did not consider “availability”  itself  as a process; “available phosphorus” or just “phosphorus” will be better. 2) Just “a subtropical forest” is not enough; please add forest type and geographical position

L31. The Plants is not a journal of microbiology, therefore please add a clear definition of “ecoenzymatic stoichiometry”. This definition is absent even in Sinsabaugh, Hill & Follstad Shah (2009) – you will be the first!

L38. “humidity”:  if you write on soil then it must be “moisture”; if it is about air or climate then it is “humidity”.

L48 Please change „stoichiometric“ by stoichiometry

L78-86.     2. Materials and Methods. 2.1. Study Region.     Please add a) description of forest type in more detail, and separately with characteristics of epiphytic vegetation on tree branches (canopy in the text); b) soil description with taxonomic name, then thickness of O and Ah, and soil texture (sand,  loam, etc). Please add also what you know on organic layer on trees’ branches (”branch floor”?) if it exists. All these are obligatory.

L109-124 2.3. Measurements of Enzyme Activities.      Please add some methodological detail for every enzyme. Citing a source only is not enough.

L128 and in the whole(!) text/figures below. NB. Please check and change In (in!)  by ln(Ln!) [that is by natural log: Ln, ln].

L135. Sentence is absent that shall logically link equations 1 and 2 to the context of this paragraph.

L162. Figure 1. Y-axis: “g^-1”:  is it g^-1(Soil, SOC or SOM)?

L168. “…all significantly offset 1,…”  it is unclear, please rewrite this sentence or paragraph.

L183. Figure 2. (a), (b) and (c) shall be additionally explained in the legend.

L185. Figure 3.  3a and 3b: name of Y-axis missed; line “28d – 329d” shall be explained in the legend. Please add more detail in the legend.

L204. Figure 5.  Excellent!

L208-210. The sentence is unclear, especially “relative carbon” and “relative phosphorus”.  May be “relative changes of carbon/phosphorus enzymes activity”?

L245  “The different stoichiometry of enzymes in different habitats reflects the difference in carbon and nutrients obtained by microbes in different habitats”  Please edit this sentence.

L269. “Many soluble compounds in litter by leaching can increase the rate of ass-loss rather than enzyme activity” Edit please.      …. ass-loss….?

My personal opinion.

I think that the “ecoenzymatic stoichiometry” represents an elegant approach with a beautiful methodology. However it is only a qualitative “signal” of nutrient deficiency for microorganisms’ growth, it has a very limited prediction capacity. This does not allow using it for quantitative assessment of P and N limitation, which is necessary for the control and prediction of ecosystems’ functioning for example by a set of simulation models.

Author Response

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Reviewer 3 Report

Leaf litter decomposition plays an important role in carbon and nutrient cycling of forest ecosystem. In this study, the process of the evergreen broad-leaved forest leaf litter decomposition in the forest canopy and on the forest floor were studied and the relationships between anzyme activity and environmental factors were discussed. To some extent, this study is novel and can provides a meaningful reference for the study of forest leaf litter decomposition in different regions. The followings are some suggestions for the article.

1. This manuscript should be checked by a native English speaker as some inappropriate expression were found in the article. For example, … and then air-dried them in the laboratory. Before experimenting, (line 90); We put… We put… We put… (line 92-96)

2. In the experimental design section, you should state clearly the total number of litter bags conducted and the number of samples in the forest canopy and on the forest floor collected for the measurement of leaf mass loss and enzyme activities every time.

3. At the beginning of the experiment, you set up the rainfall buckets and thermohygrometers in the sample plots to measure rainfall and temperature, so, the observation results should be listed in the result parts.

4. You should give the results on litter mass loss, the contents of C,N, and P every month, which can better explain the dynamics of enzyme activity in forest canopy and forest floor.

5. More previous studies on the subject should be cited to better explain the findings of this study to make the readers more convincing (lines 215-228, lines 255-258, for example).

6. lines 233-234, please check this sentence.

7. Line 265, carbon; line 270, mass-loss

Author Response

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Round 2

Reviewer 1 Report

Does it means, that plastic bags "In capopy" were hanging in the air?

Reviewer 3 Report

The authors have made great revisions according to the reviewers' suggestions. I think this paper can be accepted.