I am currently an NSF Postdoctoral Fellow in the Lasky Lab at Penn State. I completed my PhD at the University of Pennsylvania where I was a member of the Poethig and Helliker labs. Broadly, my research combines molecular, organismal and ecological approaches to understand interactions between plant environmental response, physiology and development.
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Research Interests
My dissertation research explored the ecophysiological significance of the juvenile-to-adult plant developmental transition known as vegetative phase change. This transition is regulated by an evolutionarily conserved microRNA, miR156 which is expressed at high levels during the juvenile phase and declines as the plant ages, allowing for the onset of the adult phase. Using miR156 mutants to modulate the timing of this transition in three diverse species; maize, Arabidopsis and a poplar hybrid, I investigated the role of vegetative phase change in altering photosynthesis, carbon economics and environmental stress tolerance across a plant's lifespan. During my postdoctoral research, I am incorporating evolutionary genetics and genomic techniques to ask further questions about how developmental transitions contribute to environmental adaptation and plant stress responses.
Vegetative Phase Change and Leaf Physiology:
My research works to understand how juvenile and adult leaves differ in their ability to function and photosynthesize. Leaves produced during different stages of development may function differently due to changes in structure, biochemistry and gene expression in order to best prepare the plant for the changing needs it will have throughout its lifetime. This work will help inform us on the importance of these vegetative phases and whether the timing of vegetative phase change could be a natural mechanism used to increase plant productivity or combat environmental stress.
Related Publications: Lawrence, E.H., C.J. Springer, B.R. Helliker, and R.S. Poethig. MiR156-mediated changes in leaf composition lead to altered photosynthetic traits during vegetative phase change. 2020. New Phytologist. 231(3) 1008-1022. doi:10.1111/nph.17007 PDF Lawrence, E.H., A.R. Leichty, E.E. Doody, C. Ma, S.H. Strauss, and R.S. Poethig. Vegetative phase change in Populus tremula x alba. 2021. New Phytologist. 231(1), 351-364. doi:10.1111/nph.17316 PDF |
Leaf Economics During Development:
Do juvenile and adult leaves cost the plant different amounts of resources to make? Sugar is the primary form of currency for plants and all plant structures require some form of payment to make and maintain. Often there is a trade off between cost and efficacy or longevity. This cost-benefit relationship in juvenile and adult leaves is one of the focuses of my research.
Related Publications: Lawrence, E.H., C.J. Springer, B.R. Helliker, and R.S. Poethig. The carbon economics of vegetative phase change. 2022. Plant, Cell & Environment. doi: 10.1111/pce.14281 PDF |
Developmental Timing and Response to the Environment:
Many studies have documented changes in phenology, or the timing of developmental transitions in response to environmental factors. For example, many species flower earlier when there is a warm spring. I am interested in determining how responsive the timing of vegetative phase change is to environmental factors and whether the timing of vegetative phase change impacts the success of plants facing these stresses.
Related Publications: Lawrence, E.H., R.S. Poethig, and J.R. Lasky. Vegetative phase change causes age-dependent changes in phenotypic plasticity. 2021. (Preprint available doi.org/10.1101/2021.11.02.467012) |
New Methods in Plant Physiology:
Improvements to methods in plant physiological research can help to reduce the time required to collect data and improve accuracy. One of my projects has been to develop techniques for using Rapid ACi Response (RACiR) methods in portable photosynthesis systems like the Li-Cor 6400. RACiR methods reduce the time required to determine Rubisco carboxylation rates (Vcmax) and electron transport rates (Jmax) to approximately 10 mins compared to 30-60 mins required for traditional steady-state methods.
Related Publications: Lawrence, E.H., J.R. Stinziano, and D.T. Hanson. Using the rapid A-Ci response (RACiR) in the Li-Cor 6400 to measure developmental gradients of photosynthetic capacity in poplar. 2019. Plant Cell and Environment. 42(2), 740-750 PDF |