Stress Effects on Hydrogen Peroxide Defense Response of Physcomitrella patens and Mnium cuspidatum

This project investigated the importance of stresses and the immune system response of hydrogen peroxide formation within the model system Physcomitrella patens, as well as in Mnium cuspidatum. I examined the role of two hormones, abscisic acid and jasmonic acid, along with the role that drought-like conditions play in the specified defense response of hydrogen peroxide production. I hypothesized that abscisic acid would act as an antagonist and reduce hydrogen peroxide production, jasmonic acid would act as an amplifier to increase hydrogen peroxide production and increasing the sodium concentration of the liquid treatment would also act as an antagonist. These interactions are significant to the field of Bryology as they have not been prevalent in the literature. At the conclusion of this research, it was determined that 20-minute exposure to liquid treatments of salicylic acid showed an observed upward trend in hydrogen peroxide production. In addition, abscisic acid may act as an antagonist toward SA production as reduced level of hydrogen peroxide in the presence of both hormones were found. Jasmonic acid was not tested due to lack of time and resources. Data regarding NaCl effect on H2O2 production was inconclusive, and thus further research is necessary to determine the potential interaction. These results provide further insight to how the immune systems of archaic, non-vascular plants operate, which may give further insight to the mechanisms within more modern and vascular plants, leading to potential advances in the agricultural field. Furthermore, the results provide insight into the conserved immune responses and may contribute to the collective understanding of plant evolution