Bio

Among the many constituents of a plant’s environment, water is critical to the functionality of most of a plant’s physiological processes. Given the uncertainty in global climate change's impact on plant species, my work aims to enhance our understanding of how plant physiological traits inform individual, species-level, and ecosystem responses to water stress. I use plant physiological methods and knowledge along with remote sensing tools to address scaling of variation physiology within and across species.

Honors & Awards

  • Dean's Postdoctoral Fellowship, Doerr School of Sustainability (Oct 2023 - Present)

Professional Education

  • Doctor of Philosophy, University of California Los Angeles (2023)
  • BA, Occidental College, Biology (2016)

Stanford Advisors

Contact

  • Academic
    mgbrowne@stanford.edu
    University - Scholar Department: Department of Earth System Science Position: Postdoctoral Scholar

Additional Info

Links

All Publications

  • Sensitive Hydraulic and Stomatal Decline in Extreme Drought Tolerant Species of California Ceanothus. Plant, cell & environment Zailaa, J., Trueba, S., Browne, M., Fletcher, L. R., Buckley, T. N., Brodersen, C. R., Scoffoni, C., Sack, L. 2024

    Abstract

    Identifying the physiological mechanisms by which plants are adapted to drought is critical to predict species responses to climate change. We measured the responses of leaf hydraulic and stomatal conductances (Kleaf and gs, respectively) to dehydration, and their association with anatomy, in seven species of California Ceanothus grown in a common garden, including some of the most drought-tolerant species in the semi-arid flora. We tested for matching of maximum hydraulic supply and demand and quantified the role of decline of Kleaf in driving stomatal closure. Across Ceanothus species, maximum Kleaf and gs were negatively correlated, and both Kleaf and gs showed steep declines with decreasing leaf water potential (i.e., a high sensitivity to dehydration). The leaf water potential at 50% decline in gs was linked with a low ratio of maximum hydraulic supply to demand (i.e., maximum Kleaf:gs). This sensitivity of gs, combined with low minimum epidermal conductance and water storage, could contribute to prolonged leaf survival under drought. The specialized anatomy of subg. Cerastes includes trichomous stomatal crypts and pronounced hypodermis, and was associated with higher water use efficiency and water storage. Combining our data with comparative literature of other California species, species of subg. Cerastes show traits associated with greater drought tolerance and reliance on leaf water storage relative to other California species. In addition to drought resistance mechanisms such as mechanical protection and resistance to embolism, drought avoidance mechanisms such as sensitive stomatal closure could contribute importantly to drought tolerance in dry-climate adapted species.

    View details for DOI 10.1111/pce.15208

    View details for PubMedID 39462892

  • The Ecosystem as Super-organ/Ism, Revisited: Scaling Hydraulics to Forests under Climate Change. Integrative and comparative biology Wood, J. D., Detto, M., Browne, M., Kraft, N. J., Konings, A. G., Fisher, J. B., Quetin, G. R., Trugman, A. T., Magney, T. S., Medeiros, C. D., Vinod, N., Buckley, T. N., Sack, L. 2024

    Abstract

    Classic debates in community ecology focused on the complexities of considering an ecosystem as a super-organ or organism. New consideration of such perspectives could clarify mechanisms underlying the dynamics of forest carbon dioxide (CO2) uptake and water vapor loss, important for predicting and managing the future of Earth's ecosystems and climate system. Here, we provide a rubric for considering ecosystem traits as aggregated, systemic, or emergent, i.e., representing the ecosystem as an aggregate of its individuals, or as a metaphorical or literal super-organ or organism. We review recent approaches to scaling-up plant water relations (hydraulics) concepts developed for organs and organisms to enable and interpret measurements at ecosystem-level. We focus on three community scale versions of water relations traits that have potential to provide mechanistic insight into climate change responses of CO2 and H2O gas exchange and forest productivity: leaf water potential (Ψcanopy), pressure volume curves (eco-PV), and hydraulic conductance (Keco). These analyses can reveal additional ecosystem-scale parameters analogous to those typically quantified for leaves or plants (e.g., wilting point and hydraulic vulnerability) that may act as thresholds in forest responses to drought including growth cessation, mortality and flammability. We unite these concepts in a novel framework to predict Ψcanopy and its approaching of critical thresholds during drought, using measurements of Keco and eco-PV curves. We thus delineate how extension of water relations concepts from organ- and organism-scales can reveal the hydraulic constraints on the interaction of vegetation and climate, and provide new mechanistic understanding and prediction of forest water use and productivity.

    View details for DOI 10.1093/icb/icae073

    View details for PubMedID 38886119

https://orcid.org/0000-0002-9640-0759