A case study using big-tooth aspen
Austin Frewert and Jalina Pannafino
SUNY College of Environmental Science and Forestry
MELHNE Project

 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

Hartig net of EM
(Brundrett 2008)
 In EM associations:
- Mantle around the roots
- Hartig net between cells
- External filamentous
hyphae/rhizomorphs
 Hyphae explore a long
distance in the soil
(Brundrett 2008)
 Trees associated:
- Aspen, American beech,
yellow birch, paper birch,
cherryE- endoderm
C-cortex
Arrows- 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

 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).

 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).

 It is not well understood if the phosphorous, nitrogen,
or a combination cause the decrease in colonization.
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
EM and AM in
associations in
Melaleuca
uncinata
(Brundrett 2008)

-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)

 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 stained
 AM will be assessed

 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

 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.

 Ruth Yanai
 Matt Vadeboncoeur
 Jerome Barner
 Tom Horton
 Shoestring crew 2015:
Jessica Swindon, Matt Hayden, Tyler Sadutto, Aaliyah
Jason, Isaac Jo, Nick Hoden, Jessie Smith, Briged Farrell,
Caitlin Holmes