While most plants caught in the middle of wildfires are completely incinerated, many in the edges survive despite suffering partial incineration and/or heat-induced damage. We hypothesized that heat damaged Salvia leucophylla will display a decrease in both stomatal conductance and water potential. We suspected that applying excess heat would lower the plant’s water levels and damage functional components necessary for photosynthesis, so the stomata would close to conserve water. S. leucophylla was chosen to study due to the likelihood of this widespread coastal sage to be found in the edges of wildfires in the Santa Monica Mountains. Using a heat gun, we applied sufficient heat to induce cellular death in six treatment groups, and measured their stomatal conductance, fluorescence, and water potential to compare to the six control groups. Contrary to our expected outcome, we found no difference in water potential (P > 0.05) and a significant increase in stomatal conductance (P < 0.05) in the healthy leaves that survived the applied heat. We believe the fourfold increase in stomatal conductance is a result of increased water availability per leaf and of increased demand for energy supply per leaf.
Bergin, Brigid N.; Chung, Paul; and Miranda, Laura C., "Fire Edge Effect on Water Potential and Stomatal Conductance in Salvia leucophylla" (2013). Pepperdine University, Featured Research. Paper 68.