A case study using big-tooth aspen

Austin Frewert and Jalina PannafinoSUNY College of Environmental Science and

ForestryMELHNE Project

Possible Effects of Fertilization on

Mycorrhizal Preference of Populus grandidentata

Associate with the roots of plants in a mutualistic relationship (Brundrett 2008)

Supply plants with nutrients in exchange for carbon. Make up a large portion of microbial biomass in terrestrial ecosystems (Smith & Read, 1997)

Two major classes of mycorrhizal fungi:Ectomycorrhizae (EM)Arbuscular mycorrhizae (AM)

Ectendomycorrhizal species associate with both AM and EM

Importance of Mycorrhizal Fungi

Hartig net of EM (Brundrett 2008)

In EM associations: - Mantle around the roots- Hartig net between cells- External filamentous

hyphae/rhizomorphsHyphae explore a long

distance in the soil (Brundrett 2008)

Trees associated: - Aspen, American beech, yellow birch, paper birch, cherry

Ectomycorrhizal Fungi (EM)

E- endodermC-cortexArrows- Hartig net

Arbuscule of a Glomus species (Brundrett 2008)

In AM associations: - arbuscules, hyphae, and vesicles form within the roots cortex cells

Hyphae do not explore long distances in the soil

Trees associated: - Aspen, red maple, sugar maple, striped maple, ash

Arbuscular Mycorrhizal Fungi (AM)

Ectomycorrhizal root tip abundance has been shown to decrease with increasing nitrogen concentrations (Kjøller 2012).

Increased nitrogen in the soil reduces the production of fruiting bodies in EM fungi (Arnolds 1991).

Impacts of Nitrogen

When root exploration is limited, up to 80% of phosphorous the plant receives can be sequestered by AM hyphae (Marschner 1993).

A decrease in mycorrhizal colonization has been seen in soils with high P, this is also contingent on species and the concentration of nitrogen in the soil (Baath and Spokes 1989).

Impacts of Phosphorous

It is not well understood if the phosphorous, nitrogen, or a combination cause the decrease in colonization.

Why study mycorrhizal associations?

Photo of mycorrhizae courtesy of Austin Frewert

To determine the influence of fertilization on mycorrhizal diversity

Big-tooth aspen (ectendomycorrhizal spp.) provides an opportunity to study effects of fertilization on both AM and EM associations

Objectives

EM and AM in associations in Melaleuca uncinata (Brundrett 2008)

Collecting Root Tips of Big-toothed Aspen

-Sampling will occur in buffer plots treated with N, N&P and an untreated control in site C4 (37 years old), 106 documented P. grandidentata (big-tooth aspen)

-2 trees per collection site >3 m apart ( Lilleskov et al. 2004), 2 root segments per tree (AM vs. EM)

-Younger trees < 15cm DBH, Older tree specimens > 20cm DBH

-Root-tracing method (Lucash et al. 2005)

Methods

Meanwhile back at the lab…

Aspen root samples scanned on 1 cm grid, record root length and percent colonization

Root tips sorted morphologically (AM vs. EM) under a dissecting/compound microscope

Designate 5 most prominent morphologies for EM

Roots cleared and stainedAM will be assessed

Methods

A decrease in EM colonization is expected with N additions

A decrease in AM colonization is would expected with P additions

In NP a decrease in AM and EM in increase in fine root production

Expected Results

Arnolds, Eef. "Decline of Ectomycorrhizal Fungi in Europe." Agriculture, Ecosystems & Environment 35.2-3 (1991): 209-44. Web.

Brundrett MC. 2008. Mycorrhizal Associations: The Web Resource. 7/5/15. ‹mycorrhizas.info›.

Cox, Filipa, Nadia Barsoum, Erik A. Lilleskov, and Martin I. Bidartondo. "Nitrogen Availability Is a Primary Determinant of Conifer Mycorrhizas across Complex Environmental Gradients." Ecology Letters 13.9 (2010): 1103-113. Web.

Kjøller, Rasmus, Lars-Ola Nilsson, Karin Hansen, Inger Kappel Schmidt, Lars Vesterdal, and Per Gundersen. "Dramatic Changes in Ectomycorrhizal Community Composition, Root Tip Abundance and Mycelial Production along a Stand-scale Nitrogen Deposition Gradient." New Phytologist 194.1 (2012): 278-86. Web.

Lucash, Melissa S.; Eissenstat, Dave M.; Joslin, J. Devereux; McFarlane, Karis J.; and Yanai, Ruth D., "Estimating Nutrient Uptake by Mature Tree Roots Under Field Conditions: Challenges and Opportunities" (2007). Environmental Science and Management Faculty Publications and Presentations. Paper 111.http://pdxscholar.library.pdx.edu/esm_fac/111

Smith, Sally E., and David J. Read. "Nitrogen Nutrition of Ectomycorrhizal Plants." Mycorrhizal Symbiosis (1997): 255-75. Web.

References

Ruth YanaiMatt VadeboncoeurJerome BarnerTom HortonShoestring crew 2015: Jessica Swindon, Matt Hayden, Tyler Sadutto, Aaliyah Jason, Isaac Jo, Nick Hoden, Jessie Smith, Briged Farrell, Caitlin Holmes

Acknowledgements