Acknowledgments: Dr. Johansen, University of Colorado at Denver

1. Abstract: Arabidopsis thaliana is the genetic model for all plants because it is relatively genetically simple, has a short life cycle, and its entire genome is mapped. By studying the effects of stress on Arabidopsis, predictions can be made regarding how other plants might respond to similar stress. This is especially significant in crop production. RNA interference (RNAi- see diagram for explanation of process) is used as a means of regulating protein processes by manipulating the corresponding genes. In this experiment, the genes RDR 6 and DCL 4 exemplified RNAi and were knocked out through in order to determine the response to stress involving drought. Control plants 4/16/09 Treatment plants 4/16/09 Procedure and Methods: There were a total of 12 pots, each with four Arabidopsis plants. Half of the plants were treated and the other half were the control, separated by two different containers. The control plants were watered every Monday and Thursday for 20 minutes and during the time between watering, all plants resided under artificial sunlight. The treatment plants were also watered on Mondays and Thursdays with decreasing amount s of time spent in water. The water for both treatment and control plants had one tablespoon of fertilizer per gallon. This treatment exemplified the plants response to drought. The decrease in amount of time was kept constant by a decrease in 5 min. every week. The final two weeks the treatment plants were given no water. For each watering period, all individual plant leaves were counted and the leaf with the greatest diameter per plant was measured in both control and treatment plants. Conclusion: At the conclusion of the experiment, 37.5% of the RDR 6 treatment plants remained alive and 12.5% of the DCL 4 treatment plants remained alive. All 8 of the wildtype plants died and all of the control plants died as a result of eliminating the plants’ water. In conclusion, the data shows that the RDR 6 and DCL 4 genes were effective when the plants were exposed to the environmental stress of drought. It is possible that the RDR 6 and DCL 4 genes regulate the opening and closing of stomata in addition to creating a smaller surface area to volume ratio by decreasing leaf diameter. Another expression of these genes could be an increase in root length as a means of absorbing more water, however, this data was not measured so no conclusion can be drawn based on the roots. Results in Number of Leaves and Width of Broadest Leaves per Plant Regarding Variations in the Amount of Time that the Mutant Arabidopsis Plants Lacking Genes RDR6 and DCL4 are Partially Submerged in WaterBy Jaime Winter, Kiersten Henry, Hanna Kurowski, and Chloe Ranieri Acknowledgments: Dr. Johansen, University of Colorado at Denver