Discernible Haploid Differences in
Ecotypes, an Investigation in Arabidopsis
thaliana
Ryan Pater, Department of Biological Sciences, York College of Pennsylvania
Introduction
•A member of the mustard family
(Brassicaceae), Arabidopsis thaliana has
become the model organism for research.
Scientists’ use subtle differences found in each
ecotype to understand the plant’s response to
evolutionary and environmental pressures.
(TAIR, 2012).
•John Herr’s On the Nature of Variation,
suggested studying embryo morphology as a
new method to study phenotypic variation,
allowing researchers to take a look at a new
characteristic of plants that had not been
observed extensively.
•Studies within the realm of female embryology
are broken up into two groups,
megasporogenisis and megagametogenisis.
•A Quantitative Analysis of the
Megagametophyte of Five Species of Cornus L.
by Bruce Smith was the first quantitative
analysis in the embryological study of Cornus.
(dogwood) it also was one of the first studies to
use a new clearing technique.
•There has been no published research utilizing
pistil length and ovule stage in comparing two
species' ecotypes .
•One ecotype from Graz Austria (Gr-1) and
another from Pitztal Austria (Pi-2) grow in
different environments.
Objectives
•Two ecotypes of Arabidopsis from Austria Gr-1
and Pi-2, which grow at different environments
will be compared based on pistil length and
developmental stage.
•Examine Herr Clearing technique on Gr-1, Pi-2
Hypothesis
My hypothesis is that any developmental
difference between the two ecotypes will be small
and would be due to environmental/evolutionary
pressures.
Methods
Gr-1 and Pi-2
Seeds Ordered
Results
Figure 1-4: Different
developmental stages for Gr-1;
MMC, Dyad, Tetrad and 2Nucleate , respectively.
Results
Discussion
• There is a significant correlation
between pistil length for both ecotypes
• There is a significant difference in
mean pistil length between the
developmental stages of ecotypes.
• There is a difference in the 8-N stage
• The hypothesis stated complies with
what was observed
• The Gr-1 grows larger overall, Pi-2’s
pistil length could be due to an
investment in reproduction.
• Gr-1 grows at a higher temp. and
lower altitude. This could allow for
greater investment in overall growth
Figure 5: A scatterplot showing
correlation between pistil length and
width.
Vernalization for
1 Week
Planted in
Individual Wells
Figure 6: A Two-Way ANOVA test
comparing pistil length and
developmental stage for both ecotypes.
Future Research
• Using the methods provided
to observe any difference in
two or more species
Floral Buds and
Flowers
Harvested
Literature Cited
Fixed in FPA50
For 24 Hours
Dehydrated in
ETOH Series
(70%-100%)
Placed in Herr
Fluid
Dissected,
Observed and
Measured
Table 1: Tabular results of the Two-Way
ANOVA test showing both p-value and
significance
P-Value Summary Significant?
Interaction
Column Factor
(Length)
Row Factor
(Stage)
NS
***
No
Yes
**
Total % Variation
Yes
P-Value
Interaction
Column Factor
(Length)
5.72
19.90
0.3843
<0.0001
Row Factor
(Stage)
23.26
0.0028
• Arabidopsis Information
Resource TAIR. 2008. Carnegie
Institution For Science:
Department of Plant Bio
(http://www.arabidopsis.org/)
• Bowman J. 1994. Arabidopsis.
Springer Verlay, New York NY
• Herr. J. 1967. On the Nature of
Variation. Phytomorphology. 17
(1-4): 200-207
• Smith. B. Bruce. 1975. A
Quantitative Analysis of the
Megagametophyte of Five Species
of Cornus L. Amer. J. Bot. 62(4):
387-394
Acknowledgements
I would like to thank Dr. Smith
for taking the time and having
the patience to teach me the
techniques required for this
study. I would also like to
thank Dr. Kleiner for critique
and insight on developing this
poster.