The effect of temperature on the hypocotyl growth rate of wild-type and cer10 mutant seeds of <i>Arabidopsis thaliana</i>

Abstract

Arabidopsis thaliana is a flowering plant that has an important epicuticular wax layer on its stem. This wax layer serves as a barrier against environmental stressors, such as temperature, and is composed of lipids that are produced by the enzyme, enoyl-CoA reductase (ECR). However, a deletion mutation in the cer gene coding for the ECR enzyme results in decreased deposition of cuticular wax on the hypocotyl of A. thaliana.  In light of this information, we investigated the effect of the cer10 mutation and temperature on the hypocotyl growth rate of A. thaliana seeds. Our experiment compared the average hypocotyl growth rate of wild-type and cer10 mutant A. thaliana seeds grown at 12°C, 17°C, and 30°C. The average hypocotyl growth rate of cer10 mutant seeds is lower, but not statistically significantly lower than wild-type seeds (two-way ANOVA, p-value >0.05). In addition, we found that the hypocotyl growth rate increased, though not statistically significantly, in both wild-type and cer10 mutant seeds as the temperature increased from 12°C to 17°C.  It was found that the average hypocotyl growth rates were 0.060 +/- 0.011 µm/day and 0.069 +/- 0.034 µm/day at 12°C and 17°C respectively, for the wild-type seeds,. For the cer10 mutant seeds, the average hypocotyl growth rate was 0.041 +/- 0.012 µm/day at 12°C and 0.046 +/- 0.014 µm/day at 17°C. The increased growth in the wild type versus the cer10 mutant may be due to the survival benefits that normal cuticular wax production provides, as it allows the plant to retain water necessary for growth.