Investigating Leaf Adaptation and Evolution in Living and Fossil Non-woody Monocot Flowering Plants
Creators: name: Quirk, Zack
Publisher: name: My University
Year: 2024
Subjects: subject: monocot
subject: Zingiberaceae
subject: fossil
subject: functional trait
subject: leaves
subject: climate
subject: Geology and Earth Sciences
subject: Science

description: Related dataset is at https://doi.org/10.7302/f5e0-3954 and also listed in the dc.relation field of the full item record.
description: Accompanying dataset is available here: https://doi.org/10.7302/f5e0-3954 Understanding how flowering plants adapt in changing climates is important not only for deciphering the actions of fossil plants in past ecosystems and under specific paleoclimates, but also for making predictions on how living flowering plants may respond to anthropogenic climate change. Functional leaf traits are strongly linked with a plant’s environment, climate, and other plant processes, and therefore can provide useful knowledge into the effects of these constraints on leaves, since leaves are a plant’s direct interaction with abiotic and biotic factors of their environment. Examining these functional trait-climate relationships in dicotyledonous flowering plants (dicots) has proved insightful, but many of these established relationships are untested in monocotyledonous flowering plants (monocots), despite monocots having high ecological and agricultural importance. In this dissertation, I explored the evolutionary,ecological, and climatic influences on monocot flowering plants, and later within Zingiberaceae (the ginger family) a plant group with high modern diversity and long temporal fossil record, tobetter determine leaf trait adaptation in living and fossil plants. In Chapter 2, I examined the evolutionary and ecological impacts on a well-known leaf functional trait, vein length per area (VLA) in the entire monocot clade. This work revealed that monocot VLA was more associated with a plant’s environment and its habit (size/form), rather than overall evolutionary history. Chapters 3, 4, and 5 focused on Zingiberaceae. In Chapter 3, I tested leaf functional trait-climate relationships and dicot leaf trait reconstruction methods on fossil Zingiberaceae. I found that methods used to reconstruct leaf area and leaf mass area (important leaf functional traits) in fossil dicots were not comparable for use with Zingiberaceae, and likely other monocots. Leaf venation traits, including VLA and two new traits vein thickness (VT) and distance between veins, were largely driven by changes in temperature, which may provide useful information on past plant-climate interactions. In Chapter 4 I explored leaf functional trait response to elevated temperature and [CO2] in two species of living Zingiberaceae. Venation traits were largely driven by temperature, while stomatal and leaf mass traits were strongly associated with both temperature and [CO2]. This work provided potential implications for how living flowering plants may respond to anthropogenic climate change impacts and possibly offer a plant physiology model for fossil gingers, one that is not attainable with fossils. Lastly in Chapter 5 I focused on plant climate niches across the last 100 million years and explored differences in niche expansion and contraction in woody (Metasequoia sp.) and herbaceous (Zingiberaceae) plants. This work revealed that differences in climate niches are largely due to plant growth and dispersal strategies. My results call into question assumptions made for plant-based paleoclimate reconstruction methods, and recommend further training of these methods with additional plant groups. This dissertation provides new insight on living and fossil plant-climate interactions of monocot flowering plants, and lays the foundation for future research. Future research questions include: how do leaf functional traits of other monocots react to past and modern climate changes? What other leaf traits could provide useful information on plant-climate interactions? The data presented in this dissertation should aid in other paleobotanical studies, and should serve as important basic research for applied agricultural, environmental, and biodiversity workagainst climate change.