Determining the proportion of arbuscular mycorrhizal fungal (AMF)

colonization in dune plants

Colleen MacGilvray

Arbuscular Mycorrhizal Fungi (AMF)

•  Symbiotic relationship formed between plant and mycorrhizal fungi

•  Mycorrhizal fungi grows in association with root structures

Arbuscular Mycorrhizal Fungi (AMF)

Beach Renourishment and Dune Stabilization

•  Severe erosion occurred on portions of West and South Beaches due to dredging of the Cape Fear shipping channel

•  South Beach was renourished in 2007 as a way to stabilize dune structures after erosion

•  Planting vegetation can also provide stabilization to dune structures

•  Dune stabilization is important to keep dune systems fully functioning and healthy

Dune Systems and Arbuscular Mycorrhizal Fungi

•  Diversity of AMF species present in dune systems of the Province Land Area in Massachusetts increased as the successional stage increased. (Koske and Gemma, 1997).

•  The planting of effective and efficient plants to stabilize dune structures relies on understanding the aboveground and belowground components

Purpose

•  The purpose of this experiment was to quantify the proportions of arbuscular, vesicular, and hyphal colonization between the root systems, focusing on sea oats (Uniola paniculata), among the dune systems located on the natural and renourished areas of East, South, and West beaches of Bald Head Island in order to study the effects that beach renourishment and AMF colonization have on the growth and development of the plant community of these dune systems.

Hypothesis

•  If the proportions of arbuscular, vesicular, and hyphal colonization are quantified in root systems of dune plants, specifically sea oats (Uniola paniculata), collected from dune systems of the natural and renourished beaches of Bald Head Island, North Carolina, then these proportions will differ significantly between the dune systems of the natural and renourished beaches because of differences in the growth and development of the vegetation between the study sites.

Methods

•  Obtaining root samples

•  Further dividing samples into subsamples

•  Clearing subsamples in 10% KOH

•  Staining subsamples in a 5% ink and vinegar solution

•  Preparing slides

•  Quantifying colonization by applying the magnified intersections method (McGonigle et al., 1990)

Quantifying Colonization

Results

•  Data was analyzed by performing t-tests assuming unequal variance in R to determine significance.

•  The significance factor was p ≤ 0.05.

•  Data analysis indicated that there was no significant difference between arbuscular, vesicular, and hyphal colonizations of root systems.

Relationship between colonization in samples from renourished and natural beaches

-0.05

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

Renourished Natural

Prop

ortio

n of

Col

oniz

atio

n

Study Site

Arbuscular colonization

Vesicular colonization

Hyphal colonization

Relationship between colonization in samples from renourished and natural sections of South Beach

-0.1

0

0.1

0.2

0.3

0.4

0.5

0.6

Renourished Natural

Prop

ortio

n of

Col

oniz

atio

n

Study Site

Arbuscular colonization

Vesicular colonization

Hyphal colonization

Errors

•  Fluctuating temperatures of the water bath while clearing and staining root subsamples

•  Analyzing roots under a microscope with limited magnification

•  Identifying arbuscular structures

Discussion

•  Results indicated that there was no difference in the proportions of arbuscular, vesicular, and hyphal colonizations

•  Data of no significance may have been caused by similar nutrient availability and soil composition between study sites

•  Findings may also have been impacted by a similar successional age of study sites

Discussion

•  Results quantifying AMF provide insight into hyphal colonization and soil characteristics of the renourished and natural stretches of beaches on BHI

•  Fungal colonizations in root systems may be inhibited by root density, and as root density increases the colonization of root systems by fungal interactions will decrease (Semones and Young, 1995).

•  Vesicular arbuscular mycorrhizal fungi colonization may also be influenced by soil characteristics and disturbances (Semones and Young, 1995).

Future Implications

•  Information can aid with the efficiency of replanting sand dunes, especially with competition from vegetative growths, especially invasive species

Questions?

Image Credits

•  http://www.davidmoore.org.uk/assets/mostly_mycology/diane_howarth/am.htm

•  http://rootfungi.com/tiki-index.php?page=Info%3A+Arbuscular+Mycorrhizal+Fungi

•  http://mycorrhizas.info/vam.html

•  Emam, T. (2013)

•  http://www.beachvitex.org/