Browsing by Author "Wilson, Jonathan"
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- ItemAcclimation of Ginkgo biloba Photosynthetic Biochemistry Under Elevated Carbon Dioxide: Paleo-proxy and Conservation Consequences(2021) Dougherty, James Fitzmyer; Wilson, JonathanClimate change poses an enormous threat to the world's ecosystems (Shukla et. al 2019). As a result, it is important to evaluate the ecological consequences of other climates in Earth's history. A valuable way to approximate paleo-CO2 concentrations is by using plant proxies, such as the Ginkgo biloba stomatal index - paleo-CO2 model (Barlcay and Wing 2016). To determine the reliability of G. biloba as a paleo-CO2 proxy, it is necessary to understand whether G. biloba photosynthetic biochemistry acclimates to elevated CO2. If the biochemistry is significantly different than it is under ambient conditions, researchers will need to reassess the model. We planted three ages of G. biloba in open-top chambers with different CO2 concentrations, measured photosynthetic data using a Li-cor 6400XT, and calculated biochemical parameters utilizing the Plantecophys package in R. These results suggest that the G. biloba paleo-CO2 proxy should not need major modification, since a change in Jmax is less disruptive than a change in Vcmax.
- ItemImaging Calamites: Methodologies of Investigating Carboniferous Period Plant Hydraulics(2023) Mamlin, Charles B.; Wilson, JonathanAnthropogenic climate change poses an imminent threat to humanity, and understanding how plants contribute to global climate homeostasis is paramount to mediating the effects of such change both today and for the future. Paleobotanical study, although largely undiscussed in modern discourse surrounding climate change, can provide key insights into how plants have uniquely acted as an interface between the biosphere and planetary environments throughout history. Extinct plants’ anatomical structures supply a window into the evolution of plant-level morphological traits, and environmental and climatic feedbacks through time. Measuring the dimensions of water transport cells (xylem) in extinct plants allows for the study of past hydraulic strategies, and yields insights into the history of how plant communities have responded to past episodes of climate change. During this project, we delve into the methodologies behind investigating the critical role that plant physiology has played in different planetary feedbacks throughout time. A subperiod of the Carboniferous Period — the Pennsylvanian SubPeriod (323–299 million years ago) — is of particular interest because this time period featured low concentrations of atmospheric carbon dioxide that resulted from atypical rates of organic carbon sequestration. Using light microscopy and scanning electron microscopy (SEM), we image the water transport cells of an extinct genus of Carboniferous land plant that was characteristic to swamp ecosystems and closely related to modern horsetails: Calamites. Comparing the anatomy of Calamites and other extinct taxa to modern structures can provide important context for the examination of how terrestrial plants adapt to environmental stress. These high-resolution images further illustrate the water transport morphology of Calamites at a cellular level, revealing details about its subcellular composition that can advance understanding of their ecological roles during a time of extreme climate change.
- Item“It’s the Pits!”: Imaging of Lepidophloios and Lepidodendron, Arborescent Lycopsid Tracheids(2023) Culton, Ella; Wilson, JonathanThe arborescent lycopsids Lepidophloios and Lepidodendron dominated the Middle-Pennsylvanian period, emblematic of the adaptations and vascular structure which allowed the tree lycopsids to thrive until the climatic shift of the Westphalian, bringing rise to the tree ferns. This study analyzed Lepidophloios specimen (West Mineral, KS) and an Unknown specimen (United Kingdom) using acid maceration, light microscopy, and scanning electron microscopy (SEM). Unexpectedly, the Lepidophloios specimen yielded many tracheid segments with circular border pits, rather than the anticipated scalariform pits. The Unknown specimen, which remains unidentified, yielded several promising fragments of scalariform pits. Under the scanning electron microscope only one scalariform pit was successfully identified and photographed. The tutorial and imagery developed from this study will contribute to future research of Lepidophloios and modelling the hydraulic conductance of arborescent lycopsids from the Carboniferous period.