Over the past decade, the California drought has been affecting native chaparral in the Santa Monica Mountains. Some parasitic fungi species such as Botryosphaeria dothidea have taken advantage of the drought by invading open wounds, or cankers, in a plant. When extreme environmental stress such as drought occurs, the immune system of the plant is compromised; the fungus can then multiply within the plant, blocking the vascular tissue. In this study, we aim to determine if there is a relationship between the presence of B. dothidea and an increase in the flammability of the native chaparral species Malosma laurina. Because B. dothidea blocks the xylem of a plant, we hypothesized that the kindling point of infected M. laurina would be lower than a healthy one, and that the relative percentage of water loss in infected Malosma laurina would be greater than a healthy one. The purpose of this experiment is to test whether or not the presence of B. dothidea contributes to water loss. We first weighed the stems of infected and healthy stems of M. laurina, dried them in an oven, and weighed them again. Then, to determine the kindling point, we used a conventional grill to heat stems and leaves and an infrared thermometer to measure the temperature at which combustion occurred. Results show that B. dothidea does significantly affect the water loss of M. laurina (p = 0.0119, α = 0.05) but does not significantly affect the kindling point of the stems (p = 0.07409, α = 0.05) or leaves (p = 0.1241, α = 0.05). A large standard error due to small sample sizes and a variable method may have contributed to the lack of significance for the kindling points. In conclusion, Botryosphaeria dothidea does not significantly affect the kindling point of Malosma laurina but does affect its relative percentage of water loss. Thus, the presence of the fungus clearly indicates how much water is present in vascular tissue.
Lozano, Andrew; Gribble, Michael; and Delapaz, Jared, "Botryosphaeria dothidea impacts relative water abundance in Malosma laurina" (2016). Pepperdine University, Featured Research. Paper 187.