Joesting, Heather M , Chiarello, Savannah , Medrano, Esther .
Spatial and diurnal patterns in plant and leaf morphology and physiology for the coastal sand dune shrub Croton punctatus Jacq.
The sand dune habitat can be a stressful place for plant growth and reproduction. The environment is characterized by a suite of abiotic stress factors that vary both spatially (e.g., salt spray and sand movement) and temporally (e.g., high air temperatures and incident sunlight during the growing season). Croton punctatus is a woody shrub common to the sand dune system of Georgia barrier islands and is often a dominant plant species in the primary dunes. Therefore, it would be expected for C. punctatus to possess morphological and/or physiological adaptations in response to the environment that function to promote growth and reproduction. The aim of this research was to investigate potential spatial and/or temporal patterns in plant and leaf morphology and physiology for C. punctatus in the sand dune system of Sapelo Island, Georgia, in June and July 2015. To explore potential spatial patterns, plant and leaf morphology were compared between plants located on the windward and leeward side of sand dunes. Additionally, leaf photosystem efficiency (measured as Fv/Fm) was assessed every two hours for two days to determine possible diurnal patterns in leaf physiology. Results showed that plants on the windward side of dunes had significantly larger, thicker leaves with more trichomes on adaxial and abaxial leaf surfaces in June and significantly greater plant area in July compared to plants on the leeward side, whereas plants on the leeward side had significantly greater leaf chlorophyll content in June. Furthermore, there was a significant diurnal pattern in leaf photosystem efficiency in both June and July, with decreased midday Fv/Fm values and late afternoon recovery. These results suggest that there are spatial and diurnal patterns in plant and leaf morphology and physiology for C. punctatus in the sand dune system in response spatial and diurnal variations in abiotic factors.
1 - Armstrong State University, Biology, 11935 Abercorn Street, Savannah, Georgia, 31419, United States
Presentation Type: Poster
Candidate for Awards:None