Fine-root traits from common tree species in Puerto Rico before and after Hurricane María (2017-2018)

Author(s): Yaffar D; Cabugao K; Norby R; Childs J

Site ID: PR-EVR; PR-EVV; PR-SB2; US-PR0

Site Name: El Verde Ridge; El Verde Valley; SB2: Sabana 2; Island of Puerto Rico

Variables: Root data; Soil chemical composition

Date Range: Feb. 1, 2017 - Feb. 1, 2018

Description: This dataset is a compilation of root trait measurements from common tree species in the Luquillo Experimental Forest in Puerto Rico taken in February 2017 (before Hurricane María), and in February 2018 (after the hurricane). This dataset is being used on a publication called "Tradeoffs in phosphorus acquisition strategies of five tree species in a tropical forest of Puerto Rico", where we describe below ground P-acquisition strategies of five common tree species (two pioneers and three non-pioneers) growing in the lowland tropical wet forests of Puerto Rico. Additionally, we used the unique opportunity of two consecutive hurricanes that passed over the island (Irma and Maria) to compare root traits before and after the hurricanes to determine which traits were the most responsive and whether such disturbance affected root trait relationships and trade-offs. For this, we sampled trees from El Verde 1 (EV1), Sabana 2 (SB2), and NGEE Tropics' plots El Verde Valley (EVV) and El Verde Ridge (EVR) in 2017 (before hurricanes) and 2018 (after hurricanes). Morphological fine-root traits include root length, diameter, and specific root length (SRL). Root architectural traits includes root branching ratio and intensity. Root physiological trait measured includes phosphatase activity, and root microbial association trait measured includes percentage mycorrhizal colonization. Chemistry data includes root phosphorus concentration, soil available, and organic phosphorus.

QA/QC: None

Methods Description: In February 2017 and a year after, February 2018, we took fine root samples from common tree species at the Luquillo Experimental Forest in Puerto Rico. We sampled trees located at plots EV1, SB2, and the NGEE Tropics plots EVV and EVR (here called EV). We selected individuals from each species and collected at least two root samples from each tree (composed of multiple fine-root branches) by tracing main coarse roots until reaching the fine-root system. Samples per tree were mixed to homogenize the sample. Roots were separated by root order following the morphometric classification approach. The first two root orders were scanned separately using WinRHIZO (version 12, 1400 dpi, Regent Instruments Inc., Quebec City, Canada) to obtain total root length (cm) and average diameter (mm). Root branching intensity was calculated as the number of first-order roots per length of second-order roots and root branching ratio as the number of first-order roots per number of second-order roots. The roots were then dried separately at 65°C for 48 hours. Once dried, we weighed the samples to calculate SRL (cm/gr). Then the roots were ground in 50 ml falcon tubes using a Geno/Grinder 2010 (Spex Sampler Prep, Metuchen, New Jersey, USA) and total root P (%) was measured from ground samples using a Lachat BD40 block digestor for the high-temperature digestion and a Lachat QuikChem 8000 series for the flow injection analysis (Lachat instruments, 2005). Root mycorrhizal colonization was measured by clearing, staining, and de-staining the roots (first 2 orders), following Kormanik and McGraw (1982). The presence of arbuscular mycorrhizal fungal structures (100 intersections per sample) disregarding the nature of the structures (e.g., hyphae, arbuscule, coil, vesicle) were counted under a compound microscope (200x magnification) following McGonigle et al. (1990). Root phosphatase activity was measured by the phosphomonoesterase (PME; μmol pNP groot-1 hr-1) activity from the first and second-order roots following the protocol described in Cabugao et al. (2017). Available P and organic P were analyzed following the protocol described in Cabugao et al. (2021).

Access Level: Public

Originating Institution(s): Oak Ridge National Laboratory

Sponsor Organization(s): None

Contact: Yaffar, Daniela - Oak Ridge National Laboratory (danielayaffar@gmail.com)

Version: 1.0

Dataset Citation: Yaffar D; Cabugao K; Norby R; Childs J (2021): Fine-root traits from common tree species in Puerto Rico before and after Hurricane María (2017-2018). 1.0. NGEE Tropics Data Collection. (dataset). https://doi.org/10.15486/ngt/1778242

Acknowledgement: Thanks to Nathan Stenson, Holly Vander Stel, Dianne Brice, Colleen Iversen, Tana Wood

Data Link: Download Dataset

Cabugao, K. G., Timm, C. M., Carrell, A. A., Childs, J., Lu, T. Y. S., Pelletier, D. A., et al. (2017). Root and rhizosphere bacterial phosphatase activity varies with tree species and soil phosphorus availability in puerto rico tropical forest. Front. Plant Sci. 8, 1834. https://doi.org/10.3389/fpls.2017.01834
Cabugao, K. G., Yaffar, D., Stenson, N., Childs, J., Phillips, J., Mayes, M. A., et al. (2021). Bringing function to structure: Root–soil interactions shaping phosphatase activity throughout a soil profile in Puerto Rico. Ecol. Evol. 11, 1150–1164. doi:10.1002/ece3.7036.
Kormanik, P., and McGraw, A. (1982). Quantification of vesicular-arbuscular mycorrhizae in plant roots.
McGonigle, T. P., Miller, M. H., Evans, D. G., Fairchild, G. L., and Swan, J. A. (1990). A new method which gives an objective measure of colonization of roots by vesicular—arbuscular mycorrhizal fungi. New Phytol. 115, 495–501. doi:10.1111/j.1469-8137.1990.tb00476.x.