Date of Graduation
5-2025
Document Type
Thesis
Degree Name
Master of Science in Entomology (MS)
Degree Level
Graduate
Department
Entomology and Plant Pathology
Advisor/Mentor
Joshi, Neelendra K.
Committee Member
Westerman, Eric L.
Second Committee Member
Lewis, Jeffrey A.
Keywords
Circadian rhythms; Plant–pollinator interactions; Pollination
Abstract
Pollination is an important process for the reproduction of flowering plants, yet the molecular interactions between plants and their pollinators remain inadequately understood. This gap limits our knowledge of flower development post-pollination and its relationship with environmental factors, such as time of day. While most studies focus on behavioral ecology of pollination, the influence of circadian rhythms on floral transcriptional responses is underexplored. To study the influence of circadian rhythms on floral response to pollinator activity, we chose apple flowers (Malus domestica) from the University of Arkansas orchard as a model system since their blossoms attract a variety of insects during day and night. We collected recently pollinated flowers at two time points (1 hour and 12 hours post-pollination) around mid-morning and at night for six days in spring 2022. We compared the gene expression profiles of these pollinated flowers to unpollinated flowers of the same age, apple variety, and collection time. In addition, we also assessed whether the floral transcriptional response to being pollinated at night differed from that of being pollinated during the day. Our findings reveal that gene expression patterns shift over time post-pollination, with petals showing an early response to pollination before gene activity transitions to the ovary. Furthermore, stamen tissue consistently exhibited lower differential gene expression levels post-pollination, suggesting a reduced role in short-time post-pollination responses. Distinct RNA profiles emerged between day and night-pollinated flowers, highlighting the impact of circadian rhythms on floral gene regulation. These results highlighted the importance of considering pollination timing in studies of floral gene expression and broader plant-pollinator interactions.
Citation
Ly, M. T. (2025). Circadian Rhythms and Pollination Timing: Impact on Gene Expression in Apple Blossoms. Graduate Theses and Dissertations Retrieved from https://scholarworks.uark.edu/etd/5798
