University Archives

COMPARING STOMATAL CHARACTERITISTICS OF UPRIGHT AND FALLEN SUNFLOWER PLANTS

Aleksandra Gjorovski, Sia Patel, Aya Hazime, Mohammed Bleible, and Eva Nyutuꬸ

Biology Department, University of Detroit Mercy 

Stomata are microscopic pores on plant leaf surfaces that regulate gas exchange by 
allowing carbon dioxide to enter and releasing oxygen and water vapor. Environmental 
factors, including leaf orientation, can influence stomatal behavior by affecting light 
exposure and other conditions. This study tested the hypothesis that the orientation of 
sunflower (Helianthus annuus) leaves upright versus fallen affects stomatal dynamics. 
A total of 20 leaves were collected: 10 upright, sun-facing leaves and 10 shaded, fallen 
leaves. A thin layer of clear nail polish was applied to each leaf surface to create 
stomatal impressions, which were transferred to microscope slides. Each slide was 
examined at 400X magnification, and stomatal length, stomatal density, and percentage 
of open stomata were recorded. Upright leaves had higher stomatal length, stomatal 
density and percent of open stomata compared to fallen leaves although the differences 
were not significantly different. Although previous research deduced that upright plants 
have a higher rate of photosynthesis, our study suggests that the fallen leaves might 
have been collected recently after abscission, and their stomatal characteristics may not 
have changed yet.