Plasticity of Plant N Uptake in Two Native Species in Response to Invasive Species

Round 1

Reviewer 1 Report

This manuscript reports on a greenhouse 15N labeling study that tested whether the presence of invasive species alters growth, N uptake rate, and N form preference of two native species. The authors found that while biomass is maintained, native species reduce N uptake and can shift N form is response to the presence of invasive species. The experimental design and results are clearly presented. Additional background context on native/invasive dynamics for these particular species, or at least functional groups, would help strengthen the paper introduction and discussion. Overall, the paper is a strong contribution and I have only minor suggestions detailed by line below.

Line 38 – Please expand here with specific examples

Line 48-49 – Please expand here with more details

Lines 57-59 – Specify here where these plants occur

Line 62 – What is the justification for Hyp 2? Please expand.

Line 72 – I’m not sure what you mean here, please revise this sentence.

Lines 79-83 – Include collection date, how soon after collection were they installed in microcosms? Were there two sampling locations per species? Or just two sampling locations total, one for each family?

Lines 85-92 – Additional details needed here. How big were microcosms?

Line 89 – Please expand on the purpose of the control culture.

Line 91 – What does this dry mass refer to and why is it presented here?

­Lines 123-125 – Provide more detail here on how mineral and organic N were extracted prior to analysis.

Line 134 – typo “was used”

Line 138 ANOVA already defined

Figure 2 – Here and in text, clarify whether this is total (above + belowground) biomass or aboveground only. As N uptake rates are per unit root mass, it seems important to know root mass across species.

Line 166: Remove “This section may be divided into subheadings”

Table 2. I’m not entirely clear what this table is communicating. The legend and results text that reference this table seem to be in disagreement.

Lines 215-221 – And yet these data show that native plants were able to compete and experienced no biomass decline. That should be noted here.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

In the manuscript “Plasticity of plant N uptake in two native species in
 response to invasive species” authors study the mechanisms of N uptake of native species in the presence of invasive species.

Abstract is clear

Key words are OK

Introduction is clear

I suggest adding some sentences about the effects of changed N uptake on plants metabolism.

Materials and Methods

It would be interested to know, how studied plants reproduce.

123...and NO3- concentrations were measured using an auto-analyser (AA3 ， SEAL, Germany)... delete the space.

L 134 We used one-way analysis of variance (ANOVA) followed by Duncan tests was used to examine... delete “was”

Is washed river sand and peat moss, used in the study closer to native soil of invasive or closer to native studied species in their environment? Soil is extremely important in plant growth and effect the uptake of nutrients and competiveness of the species.

Results

L 166 significantly across treatments (Table 2).This section may be divided by subheadings.  Add space please. This section may be divided by subheadings. This is not clear.

Discussion

Is OK. Are there some more literature data available concerning the uptake of N in native and alien species?

Specific comments

I would like to highlight the hard work of the authors, since there were a lot of microcosms constructed. Generally speaking, the text is clearly written, and clearly describes experiments. The methods employed are clearly explained and the results consistent with the purposes.

70 d lasting experiment is not enough to have clear insight to the studied topic. Some physiological characteristics of plants would also contribute to better understanding the effects of invasive species on the native species. However, some general facts are found out.

The main finding of the study was that native plants showed clear plasticity of N uptake. Research improves understanding the role of nutrient uptake in survival competition between invasive and native species.

I think that the MS is suitable for publication in Journal Forests because new fundamental insights in competition between native and alien species were discussed regarding the uptake of N.

Author Response

Please see the attachment.

Author Response File: Author Response.docx