University Archives

Stomatal Differences in Green  and Discolored Chestnut Leaves

Adam El-Awar, Harsha Sonawane, Laith Al-Qawasmi, Reshela Bulgareci, Mohammed Bleible, and Dr. Eva Nyutu.

Green leaves, rich in chlorophyll, are typically more efficient at photosynthesis and maintain active stomatal function for optimal gas exchange. In contrast, discolored leaves (such as yellowing or browning leaves) often indicate pigment degradation or stress, which can reduce photosynthetic activity and lead to partial or complete stomatal closure to conserve water. High temperatures can cause leaf discoloration and affect stomatal density, often resulting in yellowing or browning due to stress and the denaturation of photosynthetic pigments. The objective of this study was to compare stomatal characteristics between green and discolored chestnut leaves. We hypothesized that green leaves would have more abundant and larger stomata, with a higher percentage of open stomata than discolored leaves. An epidermal peel technique was used to measure stomatal density, stomatal length, and the percentage of open stomata in 10 green and 10 discolored leaves. Results showed that the average percentage of open stomata in green leaves was significantly greater than that in discolored leaves (P < 0.05). However, there was no significant difference in mean stomatal density or stomatal length between the two groups (P > 0.05). Healthy leaves tend to have a higher proportion of open stomata, which facilitates efficient gas exchange necessary for optimal photosynthesis and transpiration. In contrast, stressed or discolored leaves often exhibit a reduced percentage of open stomata as a protective response to minimize water loss. This research contributes to a better understanding of plant health indicators and optimal growth conditions based on stomatal behavior.