Warning flashing lights: investigating the impact of stomatal density on photosynthesis in dynamic light environments
Publication Date
July 31, 2026
Creator
Abstract
Light availability in a crop canopy is not constant. When light is available, delays in photosynthetic induction can limit crop yields. Low availability of carbon dioxide (CO2), due to slow stomatal opening, can restrict the ability of a plant to photosynthesise in dynamic light environments. Plants with mutations in their epidermal patterning factor genes, regulators of stomatal development, display variations in their stomatal density and stomatal clustering. This study tests the impact of low and high stomatal density on plant ability to photosynthesise under different fluctuating light treatments. An EPF2 overexpressor (EPF2OE), epf1epf2 loss of function mutant and Col-0 wild type Arabidopsis thaliana were grown under three different light treatments. A short fluctuating light treatment, a long fluctuating light treatment, and a constant light treatment were used. These plants were evaluated for carbon assimilation, stomatal conductance, water use efficiency, chlorophyll content, root architecture, and growth. epf1epf2 plants displayed higher stomatal conductance, photosynthetic induction rates and water use efficiency. They also showed greater growth under the short fluctuating treatment compared to the two other genotypes tested. This suggests that having a higher stomatal density and conductance allows for more photosynthesis when grown under highly fluctuating light environments compared to other genotypes. Having a faster stomatal response to changes in light intensity had a greater positive impact on water use efficiency than low stomatal density, showing that the increased photosynthetic induction rate in high stomatal density plants offsets any increase in water loss. The EPF2OE plants displayed a higher adaxial stomatal density and conductivity than expected. This suggests that low stomatal density plants can compensate for lower abaxial stomatal density by increasing their adaxial stomatal density. It also raises questions about the role of the EPF2 gene in the adaxial stomatal development pathway. The results of this study call into question the usefulness of low stomatal density genotypes in improving crop drought stress.
Item Type
ethesis
Thesis Type
MRes
Supervisors
Subjects (LC)
Associated Schools / Departments
School of Biosciences (UK)
eprints ID
83008
UoN Repository URI
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Name
Thesis final.pdf
Type
Full-text
Description
Examined
Size
2.52 MB
Format
Adobe PDF
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