CAREER: Next-generation Rhizosphere Monitoring - Non-invasive Plant Phenotyping and Health Monitoring Using the Light-piping Properties of Plant Stems

Harvey Mudd College, Claremont CA

Investigators

Abstract

An award is made to Harvey Mudd College (HMC) for the development of a new optical technology to monitor the function and structure of root systems by exploiting the light-piping properties of plant stems and roots. The project will develop a new instrument to measure quantities such as root length and growth dynamics. The education plan integrates undergraduate and high school students into the research activities where they will learn a broad set of skills at the interface of engineering, optics, and plant biology. The project will support student career development through international conference participation and individual mentorship. A 3d-printed, low-cost computational microscopy platform built around a Raspberry Pi and a connected camera will be developed as a pedagogical tool to teach optics concepts through microscopy. The project will also support the development of a curriculum of hands-on experiments to accompany the hardware platform and guide students as they explore light-matter interactions and computational microscopy techniques. Annual workshops will be offered at HMC for undergraduate and local high school students to attract students to STEM fields and offer experiential learning opportunities in engineering. The scientific research goal of the project is to exploit the light-piping property of plant stems and roots to develop the next generation of optical tools to investigate plant roots and their surrounding environments. Roots and their local underground environment play a critical role in plant health and growth. In addition to physically anchoring and stabilizing the plant, the roots provide a pathway to acquire resources from the soil and establish a chemical and biological link between the plant and the below-ground environment. This means that information about the root system is critical for plant biology and agricultural studies both in the laboratory and the field, providing quantitative metrics for monitoring and improving plant growth, productivity, and sustainability. Unfortunately, soil is not transparent at optical wavelengths and stymies direct imaging of the root systems. Current strategies to overcome this challenge include using a transparent growth medium, glass-walled imaging systems called rhizotrons, or alternative imaging methodologies such as X-ray computed tomography, magnetic resonance imaging, or positron emission tomography. However, these solutions are expensive and offer the ability to probe only a small fraction of the overall root system. The goal of this project is to develop a minimally-invasive instrument that will inject light into the stem and root system, capturing and analyzing the backscattered light to map out the root structure. The project will explore two main instrument architectures for achieving this goal: time-of-flight detection and low-coherence interferometry. In the development process, the instruments will also be used to explore the optical properties of plant stems and roots. In addition to the publication of results from this project in peer-reviewed journals and presentations at scientific conferences, instructions on how to build and operate the instruments will be made publicly available. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.