Who are We?
We are an AP Biology class in tenth grade that is part of the Blue Ridge Virginia Governor's School program. Virginia Tech provided us with the opportunity to do this experiment. They supplied us with all of the needed materials for the experiment, and our role was to test the plants and report our results.
Why Arabidopsis thaliana?
The tenth grade BRVGS class from Nelson County High School experimented on the plant Arabidopsis thaliana. The reason this particular plant was used was because it has a genome that can easily be changed or mutated. Also it has a short life span of six to eight weeks, it is small, doesn’t require a lot of care, and is related to many economically important crops.
Our Variables
In this experiment, a total of two independent variables were tested. One of these variables was the mutation of the AAP6 gene in mutant plants. This variable was tested on plants to see if they could survive and thrive without their AAP6 gene. If the plants prospered without their AAP6 gene, then the gene could be used as an alternative for pesticides and could be helpful to plant growth. The second variable was the application of a 6 millimolar solution of potassium nitrate (KNO3) on experimental plants. Potassium nitrate is used as a fertilizer in agriculture. Specifically, potassium helps a plant resist stress, perform photosynthesis, activate enzymes, and regulate water. Nitrogen helps with creating proteins and plant growth. The potassium nitrate variable was used as a stressor to test how plants with and without their AAP6 gene act in response to exposure. The dependent variable of this experiment was the growth of plants, specifically the width of rosettes, height of bolts, and number of siliques.
Hypotheses
Nelson County had a total of four hypotheses contrasting the different variations of the Arabidopsis. The first hypothesis was comparing the wild type control (WTC) plants and the mutant control (MC) plants. It was predicted that the WTC plants will have 15% larger rosettes, higher bolts, and more siliques, because the WTC retain the AAP6 gene, making them have higher growth rates. Nelson County believed that this would give them an advantage over the MC plants. The second hypothesis contrasted mutant control and mutant experimental (ME). Nelson County believed that when the mutant experimental plants were treated with potassium nitrate, they would grow 20% more than the mutant control group. This was hypothesized because potassium nitrate is commonly used as a fertilizer, which should allow it to increase the growth of the plants. When comparing wild type experimental (WTE) and mutant experimental, Nelson County predicted that WTE will grow 15% more than the ME plants. This was predicted because Nelson County students believed that the WTE had an advantage because the variation retained the AAP6 gene, causing it to have better growth rates. When comparing wild type control and wild type experimental, it was predicted that the WTE plants will grow 15% more than the WTC, because the WTE plants were treated with potassium nitrate that could have boosted their growth. A Null hypothesis was formed declaring that neither the application of potassium nitrate or the deactivation of the AAP6 gene will have any effect on the plants. The BRVGS class from Nelson County continued to reflect on these hypotheses throughout the experiment to determine if the hypotheses were correct.