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-Arabidopsis thaliana is a member of the Brassicaceae family that can be found nearly worldwide (TAIR, 2008).-Ecotypes of A. thaliana have been shown to vary in flowering time in different climates and in response to different environments (TAIR, 2008). -Variation in flowering may show differences in the haploid generation; specifically the size of the megagametophyte.-Megagametogenesis is the development of a functional megaspore into an embryonic sac. The four stages being researched are the Functional Spore, 2-Nucleate, 4-Nucleate, and 8-Nucleate. -Two ecotypes with divergent environments were chosen for this study. One from an area of rolling foothills in Russia with a severe climate and significantly low precipitation and another from the busy city of Seattle, Washington with an oceanic climate and moderate amounts of precipitation. -The Fibonacci sequence is used to compare the mean length/width ratio of the measured stages. Fibonacci provided a means of determining if there was a difference in the two ecotypes relative to when their Fibonacci phi is reached at the 10th, 11th (1.618), or 18th divisions (1.6180339) respectively. -For these expressions of Phi to appear, the mean width value must equal 20-54.5% of the mean length value to achieve 1.618 at the 11th division. It must equal 10-50.5% of the mean length to achieve 1.6180339 at the 18th division.
Introduction
Objective: To determine if the two divergent climates and environments will have a significant effect on megagametogenesis on the two selected ectoypes
Does Global Location Affect the Size of Female Megagametophytic Stages in Arabidopsis
thaliana (L) Ecotypes?Lindsay Allen Department of Biology, York College
Methods
Seeds were chosen from Seattle and Russia
Carolina Biological rapid cycling planting materials were
used
Collected flowers and stored in FPA50
Dehydrated in EtOH series (70-100%) and stored in Herr fluid
Nikon Eclipse 80i phase contrast microscope with Nikon DS-Ri1
camera and NIS elements imaging software used for imaging
Minimum of 10 measurements made per haploid stage for each ecotype and used for
Fibonacci analysis
ResultsMean Width Seattle
Mean WidthRussia
Mean LengthSeattle
Mean Length Russia
Reached Phi(1.6180339)
Seattle
Reached Phi(1.6180339)
Russia
Percent mean
length:width ratio
Seattle
Percentmean
length:width ratio
Russia
Functional Megaspore
10.71 7.55 16.34 16.66 18th division 18th division 65.54 45.32
2-Nucleate 11.55 10.70 23.20 23.25 18th division 18th division 49.74 46.02
4-Nucleate 12.78 12.92 39.07 39.94 18th division 18th division 32.71 32.35
8-Nucleate 14.24 15.11 55.11 44.86 18th division 18th division 25.84 33.68
Conclusions
Literature Cited
Acknowledgmen
ts
-ABRC. 2009. The Ohio State University. Available from http://www.abrc.osu.edu/.
-Smith, B.B. 1973. The use of a new clearing technique for the study of early ovule development,megasporogenesis,and megagametogensis in five species of Cornus L. American Journal of Botany 60(4): 322-338.
-Smith, B.B. 1975. A quantitative analysis of the megagametophyte of five species of Cornus L. American Journal of Botany. (62)4: 387-394.
-The Arabidopsis Information Resource. (TAIR). 2008. Carnegie Institution of Washington Department of Plant Biology. Stanford, California. http://www.arabidopsis.org/index.jsp.
I would like to thank Dr Bruce Smith for his constant support and guidance throughout the completion of this project.
Figure 2. 2-Nucleate stage for Russia (left) and Seattle (Right).
Figure 1. Functional Megaspore stage for Russia (left) and Seattle (right).
RationalePrevious research observed early ovule developmental stages of five species of Cornus L. using the Herr clearing technique. Differences between the species in these stages suggested the removal of C. florida from the genus Cornus (Smith, 1973). Similar research is necessary for all ecotypes of A. thaliana.
•To determine if the stages met the 18 division of Phi, the mean length and width were added in a Fibonacci series, then divided by the mean length after each new number in the series to ascertain at what division Phi (1.6180339) would be reached.• Fibonacci Series addition is expressed as Fn = Fn-1 +Fn-2
• Addition of the two prior numbers, beginning with mean length and width for each stage, yields the next number in the series.• Each division is expressed as (W+L)/L, for a ratio.
Future Research
Conduct a similar study on other ecotypes of A. thaliana to determine the relationship of an ecotypes development in terms of its environment. This could include growing ecotypes in their natural environments or growing in an opposite environment.
-The 3-decimal phi, 1.618 and 7-decimal phi, 1.6180339, were both reached at the 10th/11th and 18th divisions, respectively, for each ecotype.-Based upon the analysis of the numerical data collected, it can be concluded that the divergent environments did not affect the size of the female gametophytic stages.-The location and the environment of the two ecotypes had no significant affect on their developmental stages.
FM_Russia Division7.55
16.66 2.2066225166 124.21 1.4531812725 240.87 1.6881453945 365.08 1.5923660387 4
105.95 1.6279963122 5171.03 1.6142520057 6276.98 1.6194819622 7448.01 1.6174814066 8724.99 1.6182451285 9
1173 1.6179533511 101897.99 1.6180647911 113070.99 1.6180222235 124968.98 1.6180384827 138039.97 1.6180322722 14
13008.95 1.6180346444 1521048.92 1.6180337383 1634057.87 1.6180340844 1755106.79 1.6180339522 1889164.66 1.6180340027 19
144271.45 1.6180339834 20233436.11 1.6180339908 21377707.56 1.6180339880 22611143.67 1.6180339890 23988851.23 1.6180339886 241599994.9 1.6180339888 25
2588846.13 1.6180339887 26
FM_Seattle Division10.7116.34 1.5256769374 127.05 1.655446756 243.39 1.604066543 370.44 1.623415534 4
113.83 1.615985236 5184.27 1.618817535 6
298.1 1.617734846 7482.37 1.618148272 8780.47 1.617990339 9
1262.84 1.618050662 102043.31 1.61802762 113306.15 1.618036421 125349.46 1.61803306 138655.61 1.618034344 14
14005.07 1.618033853 1522660.68 1.618034041 1636665.75 1.618033969 1759326.43 1.618033996 1895992.18 1.618033986 19
155318.61 1.61803399 20251310.79 1.618033988 21
406629.4 1.618033989 22657940.19 1.618033989 23
1064569.59 1.618033989 241722509.78 1.618033989 252787079.37 1.618033989 26
2N_Russia DivisionWidth 10.7Length 23.25 2.1728971963 1
33.95 1.4602150538 257.2 1.6848306333 3
91.15 1.5935314685 4148.35 1.6275370269 5
239.5 1.6144253455 6387.85 1.6194154489 7627.35 1.6175067681 81015.2 1.6182354348 9
1642.55 1.6179570528 102657.75 1.6180633771 11
4300.3 1.6180227636 126958.05 1.6180382764 13
11258.35 1.6180323510 1418216.4 1.6180346143 15
29474.75 1.6180337498 1647691.15 1.6180340800 17
77165.9 1.6180339539 18124857.05 1.6180340021 19202022.95 1.6180339837 20
326880 1.6180339907 21528902.95 1.6180339880 22855782.95 1.6180339890 231384685.9 1.6180339886 24
2240468.85 1.6180339888 253625154.75 1.6180339887 26
2N_ Seattle DivisionWidth 11.54Length 23.20 2.0103986135 1
34.74 1.497413793 257.94 1.667818077 392.68 1.599585778 4
150.62 1.625161847 5243.3 1.61532333 6
393.92 1.619071106 7637.22 1.617638099 8
1031.14 1.618185242 91668.36 1.61797622 10
2699.5 1.618056055 114367.86 1.61802556 127067.36 1.618037208 13
11435.22 1.618032759 1418502.58 1.618034458 15
29937.8 1.618033809 1648440.38 1.618034057 1778378.18 1.618033963 18
126818.56 1.618033999 19205196.74 1.618033985 20
332015.3 1.61803399 21537212.04 1.618033988 22869227.34 1.618033989 23
1406439.38 1.618033989 242275666.72 1.618033989 25
3682106.1 1.618033989 26
Figure 3. Fibonacci sequence tables for Functional megaspore (Russia), Fuctional Megaspore (Seattle), 2-Nucleate (Russia) and 2-Nucleate (Seattle.)
Table 1. Summary of all data collected
