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I'm currently an NSF Postdoctoral Fellow in the Lasky Lab at Penn State. Prior to joining the Lasky Lab, I completed my PhD at the University of Pennsylvania as a member of the Poethig and Helliker labs. My research works to understand how developmental stages, in particular vegetative phase change, modifies the way plants function and interact with their environments from molecular, organismal, ecological and evolutionary perspectives.
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Research Interests
Vegetative Phase Change
Vegetative phase change is the transition between juvenile and adult phases of vegetative growth. 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 increased expression of its targets, the SPL transcription factors, and the onset of the adult phase. This transition can be visually subtle and easy to overlook in many species however, morphological and physiological differences between juvenile and adult phases can lead to meaningful differences in plant and tissue function.
As miR156 expression declines with plant development, its repression on the SPL transcription factors is alleviated, allowing for the onset of the adult vegetative phase.
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Vegetative Phase Change and Ecophysiology:
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I work to understand how juvenile and adult leaves differ in their ability ecophysiological traits. 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 |
Juvenile and adult leaves of poplar vary in leaf size, shape, specific leaf area, and maximum photosynthetic rate
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Developmental Impacts on Carbon Economics:
Juvenile leaves provide a more "acquisitive" carbon economic strategy with lower construction cost while providing a higher return on investment under low-light conditions, whereas adult leaves provide a more "conservative" strategy with a longer lifespan and a higher ROI under high-light.
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Do juvenile and adult tissues differ in their costs and benefits for the plant? Sugar is one of the primary forms 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 may contribute to differences in the function of tissues produced during these two phases.
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 Environmental Adaptation:
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The timing of many developmental transitions are plastic in response to environmental factors and contribute to local adaptation. We know very little about what natural variation in the timing of vegetative phase change looks like or how this timing responds to environmental cues. My research works to determine relationships between vegetative phase change and the environment, and whether the timing of vegetative phase change impacts the success of plants facing environmental stresses.
Related Publications: Lawrence-Paul, E.H., R.S. Poethig, and J.R. Lasky. Vegetative phase change causes age-dependent changes in phenotypic plasticity. 2023. New Phytologist. 240(2). doi:10.1111/nph.19174 |
Natural accessions of Arabidopsis thaliana with natural variation in the timing of VPC growing as part of a drought experiment where plants experience drought during different phases of development.
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New Methods in Plant Physiology:
Measuring maize photosynthesis with the LI-6400.
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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 |
