Decadal survival of tropical pioneer seeds in the soil seedbank is accompanied by fungal infection and dormancy release
Data files
Nov 08, 2023 version files 8.81 KB
Abstract
Pioneer trees require high-light environments for successful seedling establishment. Consequently, seeds of these species often persist in the soil seed bank (SSB) for periods ranging from several weeks to decades. How they survive despite extensive pressure from seed predators and soilborne pathogens remains an intriguing question.
This study aims to test the hypotheses that decades-old seeds collected from the SSB in a lowland tropical forest remain viable by i) escaping infection by fungi, which are major drivers of seed mortality in tropical soils, and/or ii) maintaining high levels of seed dormancy and seed coat integrity when compared to inviable seeds.
We collected seeds of Trema micrantha and Zanthoxylum ekmanii at Barro Colorado Island, Panama, from sites where adult trees previously occurred in the past 30 years. We used carbon dating to measure seed age and characterized seed coat integrity, seed dormancy, and fungal communities.
Viable seeds from the SSB ranged in age from 9 to 30 years for T. micrantha, and 5 to 33 years for Z. ekmanii. We found no evidence that decades-old seeds maintain high levels of seed dormancy or seed coat integrity. Fungi were rarely detected in fresh seeds (no soil contact), but phylogenetically diverse fungi were detected often in seeds from the SSB. Although fungal infections were more commonly detected in inviable seeds than in viable seeds, a lack of differences in fungal diversity and community composition between viable and inviable seeds suggested that viable seeds are not simply excluding fungal species to survive long periods in the SSB.
Synthesis: Our findings reveal the importance of a previously understudied aspect of seed survival, where the impact of seed-microbial interactions may be critical to understand long-term persistence in the SSB.
This README file was generated on 2023-11-07 by Carolina Sarmiento and Paul-Camilo Zalamea.
GENERAL INFORMATION
1. Title of the dataset: Decadal survival of tropical pioneer seeds in the soil seedbank is accompanied by fungal infection and dormancy release
2. Author information:
Principal Investigator - Corresponding author
Name: Paul-Camilo Zalamea
Institution: University of South Florida (Tampa, FL - USA) and Smithsonian Tropical Research Institute (Panama, Republic of Panama)
E-mail: paulcamiloz@usf.edu or camilozalamea@gmail.com
3. Date of data collection: July - December, 2014
4. Geographic location of data collection: Barro Colorado Island, Republic of Panama
5. Funding sources that supported the collection of the data: NSF DEB-1120205, NSF DEB-1119758, Lawrence Livermore National Laboratory-Contract DE-AC52-07NA27344
SHARING/ACCESS INFORMATION
1. Licenses/restrictions placed on the data: CC0 1.0 Universal (CC0 1.0) Public Domain
2. Publications that use the data:
Zalamea, P.-C., Sarmiento, C., Arnold, A. E., Kuo, V., Delevich, C., Davis, A. S., Brown, T. A., & Dalling, J. W. (2023). Decadal survival of tropical pioneer seeds in the soil seedbank is accompanied by fungal infection and dormancy release. Functional Ecology
3. Recommended citation for this dataset:
Zalamea, Paul-Camilo et al. (2023). Decadal survival of tropical pioneer seeds in the soil seedbank is accompanied by fungal infection and dormancy release [Dataset]. Dryad. https://doi.org/10.5061/dryad.7d7wm381z
DATA AND FILE OVERVIEW
1. File list and description:
A) Zalamea_et_al_Isolation_Frequency.csv: Isolation frequency of fungi from fresh and old seeds of Trema micrantha and Zanthoxylum ekmanii
B) Zalamea_et_al_Germination_Dormancy.csv: Percentage of seeds that were dormant and germinable from fresh and old seeds of Trema micrantha and Zanthoxylum ekmanii
C) Zalamea_et_al_Seed_Fracture_Resistance.csv: Seed fracture resistance of fresh and old seeds of Trema micrantha and Zanthoxylum ekmanii
2. Are there multiple versions of the dataset? No
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DATA-SPECIFIC INFORMATION FOR: Zalamea_et_al_Isolation_Frequency.csv
1. Number of variables: 5
2. Number of rows: 27
3. Variable list:
* species: Plant species included in this study (Trema micrantha, Zanthoxylum ekmanii)
* seed_age_years: Seed age (years) estimated using accelerator mass spectrometry (ages represent averages of three dated seed coats) or using the census year when the tree under which we collected the seed sample was first reported dead in the 50ha plot in BCI. Seed age 0 refers to fresh seeds i.e., seeds that were collected from trees and were not buried
* viability: Seed viability estimated using 2, 3, 5-triphenyl tetrazolium chloride (viable = alive, inviable = dead)
* total_number_seeds: Total number of seeds that were screened for fungal growth
* isolation_frequency: Fungal isolation frequency estimated as the number of seeds/cultures that had fungal growth divided by the total number of screened seeds
4. Missing data codes: None
5. Specialized formats or other abbreviations used: None
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DATA-SPECIFIC INFORMATION FOR: Zalamea_et_al_Germination_Dormancy.csv
1. Number of variables: 5
2. Number of rows: 21
3. Variable list:
* species: Plant species included in this study (Trema micrantha, Zanthoxylum ekmanii)
* seed_age_years: Seed age (years) estimated using accelerator mass spectrometry (ages represent averages of three dated seed coats) or using the census year when the tree under which we collected the seed sample was first reported dead in the 50ha plot in BCI. Seed age 0 refers to fresh seeds (i.e., seeds that were collected from six different maternal sources and were not buried)
* total_number_seeds: Total number of seeds that were used for the germination/dormancy assays
* germination_percentage: Percentage of germinated seeds calculated as the number of germinated seeds that germinated divided by the total number of seeds that were used for the germination assays
* dormancy_percentage: Percentage of dormant seeds calculated as the number of seeds that did not germinate in the germination assays but that were viable (alive) after testing with 2, 3, 5-triphenyl tetrazolium chloride (i.e., dormant seeds) divided by the total number of screened seeds
4. Missing data codes: None
5. Specialized formats or other abbreviations used: None
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DATA-SPECIFIC INFORMATION FOR: Zalamea_et_al_Seed_Fracture_Resistance.csv
1. Number of variables: 5
2. Number of rows: 25
3. Variable list:
* species: Plant species included in this study (Trema micrantha, Zanthoxylum ekmanii)
* seed_age_years: Seed age (years) estimated using accelerator mass spectrometry (ages represent averages of three dated seed coats) or using the census year when the tree under which we collected the seed sample was first reported dead in the 50ha plot in BCI. Seed age 0 refers to fresh seeds (i.e., seeds that were collected from six different maternal sources and were not buried)
* viability: Seed viability estimated using 2, 3, 5-triphenyl tetrazolium chloride (viable = alive, inviable = dead). For fresh seeds (i.e., seed age = 0) viability was not recorded (NA, data not available)
* total_number_seeds: Total number of seeds that were used for the seed fracture resistance test
* seed_fracture_resistance: Seed fracture resistance (in Newtons (N)) defined as the minimum force required to initiate seed coat rupture, measured using an Instron Single Column Testing System Model 3342 (Instron Company, USA). The shown values represent the average seed fracture resistance of the total number of seeds individually tested
4. Missing data codes: NA (data not available)
5. Specialized formats or other abbreviations used: None
Seeds were extracted from soil cores by rinsing the soil with tap water under a series of sieves, with a minimum pore diameter of 2 mm for Z. ekmanii and 1 mm for T. micrantha. Seeds were identified to species and then partitioned for tests of i) seed viability measured using the tetrazolium test and seed-endophyte isolation frequency (692 and 593 seeds of T. micrantha and Z. ekmanii, respectively), ii) germination (% of germinated and dormant seeds) and carbon dating (a total of 239 and 196 seeds of T. micrantha and Z. ekmanii, respectively, where 9 viable seeds of each species were carbon dated), and iii) average seed fracture resistance as a measure of seed coat integrity (224 and 142 seeds of T. micrantha and Z. ekmanii, respectively).
- Zalamea, Paul‐Camilo et al. (2023), Decadal survival of tropical pioneer seeds in the soil seed bank is accompanied by fungal infection and dormancy release, Functional Ecology, Journal-article, https://doi.org/10.1111/1365-2435.14476