Temperature Stress Project One

Project by group gehsbeardsleyfall2019

Explore In our experiment, we will be comparing out wild type Columbia, to hit1-1 and hot5-1 mutants. First, hit1-1 has an increased thermotolerance, due to a mutation at gene AT1G50500. Under normal temperatures, the protein doesn’t show any difference in growth in comparison to the wild type. However, when the temperature is risen, it shows resistance to the stress the heat puts on it. Vesicle trafficking allows for the proteins and lipids to exit the membrane while newly synthesized materials enter. The vehicle trafficking is in a sense “recodes” the way the plant functions. Similarly, vesicle trafficking is thought of as rebuilding it, rather than helping it. These results influences a stronger protection against heat stress. On the other hand, the hot5-1 mutant had 4 other mutants before it, as the name suggests. In the hot mutants, there appears to be a decrease in the heat shock protein (HSP) which protects the plants from heat. The hot5-1 has a mutation at AT5G43940. The reduction in the HSP makes it more susceptible to heat, hindering the growth.
Research Question How does the gene mutation, hit1-1, vary in stem growth and leave growth in comparison to wild type Columbia and hot5-1, when put under rapid and constant fluctuations in extreme temperature?
Predictions When grown in an environment with constant fluctuating temperatures, the wild type Columbia and hot5-1 will be outgrown by mutant gene hit1-1. This is because we know that the hit1-1 withstands short temperature flashes. Since the plants are only exposed to excessive heat for seven hours a day, we expect hit1-1 to overcome this. The wild type will be close behind in height and leave length. Hot5-1 has an increased temperature susceptibility, therefore we do not expect it to last long in the heat.
Experimental Design In this experiment, we plan to set up a control of the three types of A. thaliana mutants (hit1-1, hot 5-1 and wild type) and a manipulated group of A. thaliana. In this manipulated group, the plants will be exposed to a variety of temperature extremes. During the day, the plants will have a heat lamp shining (103-112 degrees F) onto it, with a distance of 8.5 inches. Due to the range in the temperatures from each of the three different heat lamps, the pots are each rotated to a new lamp each day to even out the temperature. During the night, the plants will be moved towards a window, which is very drafty during the night. This is meant to represent an environment which has cool nights, hot days. A lamp will be set up only during the day for approximately 7 hours. The lamps will be hanging from a fixture, shining down on three plots of plants. The distance between the lamp and the countertop is 8.5” inches, and shines down at 103-112 degrees F. The constants are: the plants will be given the same amount of water per day for both the control and manipulated group; the temperature of the lamp will be the same throughout the day. Our independent variable is the different exposure of temperatures. We will be recording the dependent variable, the growth of the stem and the average growth of the leaves will be measured in centimeters.
Conclusion The results from both the insignificant data and the significant data does not support the hypothesis in terms of which plants would grow the best. There proved to be no significance of stem length difference between hot5-1, hit1-1 and WT-Col under normal temperatures when compared to the stem lengths under heat (respectively, p=.38, .46 and 8.54) There proved to be a link of leaf length difference between hot5-1, hit1-1 and WT-Col under normal temperatures when compared to the leaf lengths under heat (respectively, p=.0437, .001, .001). Surprisingly, hot5-1, which was predicted to do the worst, did the second best. hit1-1 was very low in growth and consistently was low for every experimental group and every measure of experiment. For the sake of this experiment, there were too many errors in the experimental design to definitively say that the heat directly caused the differences in growth. The biggest flaw in the experimental design is the way the heat was put onto the plants. It was too close to the plants, with a very strong wattage. This lead to extreme concentrations of heat onto the plants, causing cell death. If to be done again, the bulb would have to have a much smaller wattage. Additionally, the sample size was incredibly small. The plants had to be inconsistently taken off the heat, so there is no consistent stress at no consistent temperature. The sample size was cut in half and started over within the middle of the experiment.