Environmental Internship Program - 2023 Booklet

Angelica She ’26
CIVIL AND ENVIRONMENTAL ENGINEERING
PROJECT TITLE
Potassium Isotopes in
Plants: A Hydroponic
Investigation With
Arabidopsis
ORGANIZATION(S)
Higgins Lab,
Department of
Geosciences,
Princeton University
LOCATION(S)
Princeton, New Jersey
MENTOR(S)
John Higgins,
Professor of Geosciences;
Mason Scher, Ph.D.
candidate, Geosciences
Potassium is a vital plant nutrient and the
most abundant cation in plants. In addition
to regulating the opening of a plant’s
stomata, through which gas is exchanged for
photosynthesis, potassium also helps with pH
maintenance and enzyme activation. Though
potassium transport systems in plants are
well studied, little is known about potassium
isotope fractionation — the relative partitioning
of light and heavy isotopes — associated with
those transport systems. To fill this gap, we
conducted a hydroponic growth experiment
with Arabidopsis, a model plant, to investigate
the relationship between potassium isotopic
compositions and a plant’s transport system.
I started the seeds in a control condition with
plenty of potassium before transferring them to
growth buckets supplied with nutrient solutions
of varying potassium concentrations. I recorded
plant growth, replenished nutrient solutions and
sampled the plants after the experiment. I also
dried and ground the plant parts into powders
to be dissolved in nitric acid and analyzed
for potassium concentration and isotopic
composition. As the specks of seeds grew into
tall plants with budding flowers, so, too, did my
confidence in experimental work and aspirations
to create environmental change through
research, engineering or both.
FOOD SYSTEMS
AND HEALTH
63