-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 ( ) respectively. -For these expressions of Phi to appear, the mean width value must equal % of the mean length value to achieve at the 11 th division. It must equal % of the mean length to achieve at the 18 th 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 ( %) 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 Results Mean Width Seattle Mean Width Russia Mean Length Seattle Mean Length Russia Reached Phi ( ) Seattle Reached Phi ( ) Russia Percent mean length:width ratio Seattle Percent mean length:width ratio Russia Functional Megaspore th division Nucleate th division Nucleate th division Nucleate th division Conclusions Literature Cited Acknowledgments -ABRC The Ohio State University. Available from -Smith, B.B 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): Smith, B.B A quantitative analysis of the megagametophyte of five species of Cornus L. American Journal of Botany. (62)4: The Arabidopsis Information Resource. (TAIR) Carnegie Institution of Washington Department of Plant Biology. Stanford, California. 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). Rationale Previous 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 ( ) would be reached. Fibonacci Series addition is expressed as F n = F n-1 +F n-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, and 7-decimal phi, , were both reached at the 10 th /11 th and 18 th 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_RussiaDivision FM_SeattleDivision N_RussiaDivision Width10.7 Length N_ SeattleDivision Width11.54 Length 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