1. Eight conventional Petri dishes containing 0.8% agar Castrol motor oil (5W30 ) Eighty Arabidopsis (ecotype- Columbia) seeds Image J Software Fluorescent grow lights Standard agar was mixed with motor oil to obtain 0%, 0.01%, 0.1%, and 1% dilutions. The agar containing motor oil required extensive mixing to disperse the oil before pouring on to slanted petri dishes. We then planted 10 seeds of Arabidopsis in each of eight Petri dishes; 2 dishes for each concentration. Seeds were placed at the upper edge of the agar on each of the plates. Agar was used rather than soil so that we could measure the roots without removing the plant from its substrate. The dishes were sealed and vertically placed beneath fluorescent grow lights at a distance of 33cm throughout the experiment. The two dishes with 0% motor oil in agar served as the control group, while the other six had the concentrations of the petroleum product. Each of the plates had equal photoperiods (16 hours of light and 8 hours of dark) 33 cm below a fluorescent light. Once a week for two weeks, we measured the length of the roots using Image J software (see picture below) from scans of each plate. We were able to accurately see and measure roots and shoots for individually identified seedlings. Only root measurement data are presented here.. The Effects of Oil Contamination on Root Growth of Arabidopsis Matt Steelman, Josh Fester, Tinus Van Wyk, and Nicole Sowers Wofford College, South Carolina Methods Introduction Discussion Some Arabidopsis ecotypes such as those from Ireland and Bulgaria grow on roadsides where petroleum runoff could affect their growth. In an experiment using phenanthrene as the pollutant, Arabidopsis plants were shown to be negatively affected 1. Our purpose is to investigate to what extent, if any, the root growth of Arabidopsis is affected by contamination with motor oil. In this experiment, we used ecotype Columbia because it is the most commonly used ecotype in laboratory studies. Also, we chose our concentrations of motor oil in agar with the desire to avoid killing the plant while providing adequate range that would produce an observable response. Firstly, germination was not affected by motor oil in agar, suggesting that environment is less important than conditions inside the seed for germination. Secondly, our results support the hypothesis that an increased concentration of motor oil in agar stunts root growth. Although there was no different in root growth from 0% oil to 0.01% oil, but at the higher concentrations (0.1% and 1%) root growth was significantly reduced compared to control. In general, root growth is negatively affected by increased concentrations of motor oil. Implications of this Experiment The results of this experiment show that while plants can tolerate low levels of motor oil pollution, increased concentrations are detrimental to root growth. It would be unwise to assume that all seedlings respond to oil pollution in the same way as Arabidopis thalania ecotype Columbia. It is likely that other ecotypes or other species of plants have greater or lesser sensitivity to oil in the soil. Future Experiments We recommend that future experiments find a more effective way to measure the root such as removing them from the agar. Also, the experimenter must make sure that light is evenly distributed to each agar plate. Another issue that should be addressed is clumping of motor oil in the agar which may allow roots to avoid the pollution by growing in the agar between the droplets of oil. Finally, effects of the motor oil on root growth in agar may be different than those in soil, so perhaps soil should be used in a follow-up experiment. Results Acknowledgements Hypothesis The addition of motor oil into the agar for Arabidopsis thaliana ecotype Columbia will significantly stunt the growth of the root. Germination Germination was unaffected by oil dissolved in the agar (p=0.667, χ2 with 6 degrees of freedom = 4.08, data not shown.) Root Growth At the lowest concentration of oil (0.01%) root growth was not significantly different from the control group. However, root growth was decreased at the higher concentrations of oil in agar (p=0.001, Analysis of Variance F dF= 3, 70 = 6.054.) References Special thanks to GR Davis and C. Abercrombie for their assistance with statistical analysis and answering of questions. Also, thanks to A. Steadman and T. Player for their comments and suggestions. Root Growth and Oil Concentration Bars are 95% confidence intervals. 1) Lui, Hong. “An oxidative stress response to polycyclic aromatic hydrocarbon exposure is rapid and complex in Arabidopsis thaliana.” Plant Science: Vol. 176 Issue 3 March 2009 pg. 375-382.