Megan Seawright
Plant Biology Lab 3146.002
November 17, 2015
Plant Response to Mechanical Stimulation
INTRODUCTION
The purpose of this lab was to conduct an experiment testing how some sort of mechanical stimulation will affect the overall growth of a plant. The various ways plants respond to mechanical stimulation such as wind or touch is known as thigmomorphogenesis (Johnson et al., 1998). We were provided with Arabidopsis thaliana seeds. Arabidopsis thaliana is commonly known as Mouse-Ear Cress. It is mainly found in pastures or wasteland throughout Eurasia, North Africa, and parts of North America and Japan (Banta and Purugganan, 2011). Although small and short-lived, A. thaliana is known for its fast growth (Banta and Purugganan, 2011).…show more content… One side of the container was labeled experiment, and the other side was labeled control. Fifteen slots on each side of the container were filled with one seed in each slot. The tray was kept in a growth chamber which was filled with many lights and set between 22⁰C-24⁰C. We watered our plants once a day by filling the bottom part of the soiling tray with tap water just high enough to where it touched the bottom of the pockets that held the seeds, and then we sprayed the top of the soil with distilled water from a spray bottle. Our experiment was to test how the plants would respond to us rubbing the stems for one minute each day. At first, we had to wait until the plant stems were long enough for us to rub the stem without killing the plant. The first day we did treatment we took an initial height of the plants that began to shoot up, and the shortest height came out to be three centimeters tall. This was about two weeks after the seeds were planted. The plants were fully above the ground and had begun to bolt. To rub the plant stem, we gently placed two fingers around the stem of the plant and rubbed up, down, and all around the stem for one minute a day on each sprouted plant. The plants were about 21 days old when we completed our treatments to the stems and took their heights. To measure the height, we placed a small ruler directly on top of the soil at the base of the plant and measured all the way to the…show more content… In other words, the control and experimental group were not significantly different in the final outcome.
DISCUSSION
I hypothesized that rubbing the plant stems of A. thaliana will stunt the overall growth of the plant because stress and acids from our oily skin will keep them from growing at their normal pace. Our results did the exact opposite of my hypothesis. Our control group plants ended up being shorter than our experimental. Our results may be completely different than what we predicted because we may not have had enough time to give our planned treatment to the stems. We also had three members in our group and each one of us could have slightly done the treatment differently. We all had the general idea of rubbing the plant, but one of us might have added more pressure, counted a minute in our head rather than by watch, or added too much or too little of water. My prediction would still be the same if we could do the experiment over again because research shows that mechanical stimulation, such as we did, will stunt the overall growth of the plant, but I would modify the experiment so there are less variables to affect the outcome. Only one person would do the testing on the plants, and they would do it at a set time every day. This minimizes