HUBBARD BROOK ECOSYSTEM STUDY, 52nd ANNUAL COOPERATORS' MEETING, Woodstock NH, Wednesday, 8 JULY 2015. Session l: Multiple Element Limitation Study Moderator: Ruth Yanai. Mychorrhizal preference change in aspen: AM vs. EM and N vs. P Austin Frewert and Jalina Pannafino, SUNY ESF This study evaluates Ectomycorrhizal colonization in the different treatment plots by counting the number of EM root tips to determine if EM colonization is less pronounced with fertilization. Both Ectomycorrhizae and Arbuscular Mycorrhizae are evaluated on the root tips of Aspen in treatment plots where it is present.

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

2.  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

3. 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

4. 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

5.  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).

6.  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).

7.  It is not well understood if the phosphorous, nitrogen,
or a combination cause the decrease in colonization.
Photo of
mycorrhizae
courtesy of Austin
Frewert

8.  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)

10. -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)

12.  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

13.  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

14.  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.

15.  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