UV-treatment of the digestive fluid of Nepenthes hemsleyana pitcher plants affects their digestive process, possibly via reducing microbial inquilines
Data files
Jun 11, 2025 version files 51.46 MB
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chl_fluoresc_fvfm.csv
8.45 KB
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chl_fluoresc_induction_curve.csv
155.61 KB
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chl_fluoresc_light_curve.field.csv
74.71 KB
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foliar_nutrient_content.csv
4.03 KB
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plantgrowth.csv
2.04 KB
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R_Scripts.zip
50.94 MB
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README.md
6.38 KB
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S1-2_Enzyme_activity.zip
269.18 KB
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youngest_leaf.csv
2.35 KB
Abstract
Interactions with microbes are ubiquitous, and many of them are essential for the survival and success of plants. In Nepenthes pitcher plants, they occur as part of a diverse community of organisms, so-called inquilines, that live inside the digestive fluid of the pitcher traps. However, evidence is ambiguous regarding the role of microbial inquilines: they may complement the plants’ prey digestion, fix atmospheric N, act as competitors that reduce plant-available nutrients, or affect the plants in other ways unrelated to the breakdown of prey. In a field experiment on Borneo, we investigated the effect of a UV-disinfection of the digestive fluid on prey digestion of N. hemsleyana that captures and digests insects as well as bat faeces in its pitchers. We show that in the short term photosynthetic performance of plants with UV-treated digestive fluids decreases compared to untreated plants, likely due to lower abundances of microbial inquilines. However, at the end of two months, responses of pitcher plants with UV-treated and untreated digestive fluids tend to equalise. Nutrient source, whether from insects or bat faeces, does not influence prey digestion. We expect our findings to be a starting point for unveiling the ecological role of microbial inquilines in pitcher plants and how they interact with other inquiline groups of higher trophic levels. Ultimately, this will also help to improve understanding of the functioning and evolution of convergent interactions in other carnivorous plants.
https://doi.org/10.5061/dryad.00000009p
Julien L. Bota, 2025-05-28
In a field experiment on Borneo, we investigated the effect of UV-sterilisation of the digestive fluid in the pitchers on prey digestion in N. hemsleyana. We selected 24 N. hemsleyana plants and supplied two pitchers per plant with either arthropods or bat faeces as prey items. To assess the role of microbial communities in digestion, half of the plants in each feeding treatment were randomly assigned to a UV-sterilisation group, which likely reduced microbial abundance in the digestive fluid.
Description of the data and file structure
We applied four treatments:
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Arthropods: 5 mg arthropods
- Arthropods + UV: 5 mg arthropods + UV sterilisation of digestive fluid for 48 s
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Faeces: 6 mg bat faeces
- Faeces + UV: 6 mg bat faeces + UV sterilisation of digestive fluid for 48 s
For a detailed method description, please refer to the original publication.
Not available values are noted as NA in the data files.
Chlorophyll a fluorescence
We measured chlorophyll a fluorescence of the youngest fully developed leaf on days 0, 28 and 56 with a portable photosynthesis yield analyser (MINI-PAM II, Heinz Walz GmbH, Effeltrich, Germany). For exact settings and methods, refer to the original publication.
Files:
- chl_fluoresc_fvfm.csv: Fv/Fm measurements
- chl_fluoresc_induction_curve.csv: measurements of induction curve programme
- chl_fluoresc_light_curve.csv: measurements of light curve programme
Variables:
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date
- record_time
- type
- treatment.id
- prey: fed prey type (Arthropods/Faeces)
- uv: sterilisation of fluid (sterile), no sterilisation (nonsterile)
- set: set-id (replicates were assigned to sets that were blocked in time)
- plant.id
- species
- day: measuring days 0, 28, 56
- programme: programme of measuring device
- time: measuring timepoint in s after start of programme
- F_: The F corresponds to the momentary fluorescence level (Ft) of an illuminated sample measured shortly before application of a Saturation Pulse
- Fm_: Maximum fluorescence level of the illuminated sample FM’
- PAR: Quantum flux density of photosynthetically active radiation (PAR) impinging on the sample
- YII: effective photochemical quantum yields of PS II
- ETR: Relative electron transfer rates
- Fo_: Minimum fluorescence level of illuminated sample F0’
- ETRFac: Sample absorptance (= 1 – transmittance)
- qP and qL: Coefficients of photochemical fluorescence quenching
- qN and NPQ: Parameters of non-photochemical quenching
- YNO: non-regulated losses of excitation energy, including heat dissipation and fluorescence emission
- YNPQ: regulated energy losses of excitation energy by heat dissipation involving ∆pH- and zeaxanthin-dependent mechanisms
- Fo: Minimum fluorescence level
- Fm: Maximum fluorescence level
- FvFm: Maximum photochemical quantum yield of PS II, FV/FM
Elemental analyses
We marked the youngest fully unfurled leaf of each pitcher plant and harvested it at the end of the experimental period to determine total concentrations of carbon, nitrogen and sulphur with a CNS-Analyzer (Vario EL, Fa. Foss Heraeus, Hanau, Germany) using air-dried and milled plant material (DIN ISO 10694: 1996-08).
File: foliar_nutrient_content.csv
Variables:
- ID: treatment-ID
- sample_number
- Ca, K, Mg, P, Zn, N, C, S: in mg/g
- Fe: µg/g
- N.P: N:P ratio
- N.K: N:K ratio
- K.P: K:P ratio
- plant.id
- prey: fed prey type (Arthropods/Faeces)
- uv: sterilisation of fluid (sterile), no sterilisation (nonsterile)
- set: set-id (replicates were assigned to sets that were blocked in time)
- species
Measurement of plant growth
We counted the number of newly developed pitchers (> 0.5 cm in length), the number of newly developed leaves, the cumulative leaf surface area of all fully developed new leaves and the specific leaf area of the youngest fully developed leaf at the end of the experiment.
File: youngest_leaf.csv
Variables:
- treatment.id
- plant.id
- prey: fed prey type (Arthropods/Faeces)
- uv: sterilisation of fluid (sterile), no sterilisation (nonsterile)
- set: set-id (replicates were assigned to sets that were blocked in time)
- species
- area_mm2: leaf area in mm^2
- area_cm2: leaf area in mm^2
- dry_weight_g: leaf dry weight in g
- comment
File: plantgowth.csv
Variables
- treatment.id
-
plant.id
- prey: fed prey type (Arthropods/Faeces)
- uv: sterilisation of fluid (sterile), no sterilisation (nonsterile)
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set: set-id (replicates were assigned to sets that were blocked in time)
- species
- L-1_mm2; L-2_mm2; L-3_mm2; L-4_mm2: leaf area of newly produced leaves (1-4), measured at the end of the sampling period in mm2. L-1 is always the oldest leaf.
- leaves: number of newly produced leaves over the sampling period
- pitchers: number of newly produced leaves over the sampling period
- comment
R Scripts
Find all R scripts used to analyse the data here. The zip folder contains three folders:
- Foliar nutrient content
- PAM-Measurements
- Plant growth
There you can find the scripts used for data preparation, statistical analysis, and plotting as R-Markdown (.Rmd) and as an HTML file (.html). If required by the main script, an additional R script containing parameters for plotting is added to the folder.
S1-2_Enzyme_activity
Data and statistical analysis of the additional experiment that was performed to measure the impact of the UV-treatment on plant enzyme activity (Supplement 1.2).
File: Azocassein_Nepenthes_hemsleyana-2022-02-09.csv
Variables
- Species
- Treatment: applied feeding treatment
- Replicate: replicate number
- A: sample absorption at 440 nm
File: Enzyme_activity-azocassein_assay.Rmd and Enzyme_activity-azocassein_assay.html
- Script used for data analysis, provided as an R-Markdown file and HTML
File: graphic parameters.R
- R script containing parameters for plotting