University Archives

Stomata are pores on leaf surfaces that regulate gas exchange by allowing carbon dioxide to enter while releasing water vapor and oxygen. Environmental factors, including elevation, could influence the behavior of the stomata by affecting its light exposure, humidity, and temperature. Our study tested the hypothesis that elevations on a single chestnut tree affect the % of stomata open. We collected 20 leaves in total, 10 from the higher elevation, and 10 from the lower elevation of the tree. A thin layer of nail polish was applied to the surface of the leaf to create a peel which was then placed on a labeled slide under the microscope. The slides were labeled H for high elevation and L for low elevation. Under the microscope, we measured stomatal density and the percentage of open stomata for each sample.  Leaves from the lower elevation of the tree showed a greater stomatal density and a higher percentage of open stomata compared to those in higher elevation. The average stomatal density for high elevation was 258.7 while the average for low elevation was 202.5. The percentage of open stomata was 23% in high elevation and 31% in low elevation. These results show us that leaves in the lower elevation have more open stomata to maximize gas exchange in areas with greater humidity and shade. Overall, our findings support the hypothesis that elevation affects stomatal opening.