Zinc Treatments Increase Plant Yield in High CO2, Resisting Effects of Climate Change on Plants

AJAS · 2022 Environmental Science

Talia Smith

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Overview

The increase in greenhouse gases which causes global warming can also lead to a decrease in the nutrient content of crops, which can impact global malnutrition. Zinc is one of the plant micronutrients most affected by elevated atmospheric carbon dioxide (CO2). Zinc deficiency is harmful to human health and can stunt growth and impair immune function. In this novel study, zinc oxide (ZnO) nanoparticles were investigated as a potential means of biofortifying plants against the effects of increased CO2 conditions. Biomass can be a relative indicator of zinc content. ZnO nanoparticle treatments were hypothesized to increase biomass, but only to a certain point, as micronutrients can become harmful at higher concentrations. Arabidopsis thaliana plants were grown in ambient and elevated CO2. Each trial contained ten groups that were treated with various concentrations of ZnO nanoparticles, which were delivered using two different methods. Half of the plants in each trial were soaked as seeds in a solution of ZnO nanoparticles for three hours before being planted, which is a treatment used in other studies, and then watered with 0.5 mL of regular distilled water during growth. The other half of the seeds were watered every three days during growth with 0.5 mL of the solution of ZnO nanoparticles. The concentrations used for each method were 0.0 (control), 0.5, 1.0, 5.0, and 10.0 mg/L of ZnO nanoparticles. After three weeks, the dry biomass above the root was measured. Overall statistical significance was determined by ANOVA tests and post-hoc Tukey tests were used for comparisons between treatments. In ambient CO2, the 5.0 mg/L soaking treatment yielded the highest mean biomass (p = 0.001 compared to control) and the second-highest mean biomass in elevated CO2 (p = 0.001 compared to control). 5.0 mg/L was also more effective than all watering treatments under both ambient and elevated conditions (p = 0.001), indicating that Arabidopsis thaliana biomass is more affected by three hours of soaking as a seed in the 5.0 mg/L solution than by three weeks of watering with the solutions. 5.0 mg/L was identified as a possible optimal concentration of ZnO nanoparticles to maximize biomass. The presence of ZnO nanoparticles effectively increases crop yield and may be a viable strategy to combat zinc loss due to increased CO2. As plants are a vital source of zinc for humans around the globe, especially in low-resource areas, measures to stabilize micronutrients in plants must be considered as a response to climate change.

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My Story

I believe that climate change is one of the most pressing issues for our generation and will likely have far-reaching effects. As I began my third high school research project in the summer of 2020, I knew that I wanted to take a proactive step toward finding how we can mitigate the effects of climate change, especially concerning nutrition.

I found that previous studies had already completed an experiment that I was thinking of, which was testing the effects of excess carbon dioxide on plant nutrient content. The researchers found that plant nutrient content decreases in environments with elevated carbon dioxide, which sparked this project. I focused on the mineral zinc and aimed to increase plant yield, which can be indicative of zinc content, in environments with high carbon dioxide. The purpose was to help plants retain their nutritional properties in climate change conditions that typically have negative effects on nutrients. I wanted to take an active approach in my project to prevent plant micronutrient loss in climate change conditions.

Over the course of six months, I was in the lab at my school every few days to treat and measure over 800 plants. The process began with treating and transferring microscopic seeds one-by-one, and ended with uprooting their leafy structures and measuring how much they had grown over several weeks. I am very grateful for my mentor, Dr. Crowthers, who supported me throughout my project ideation and experimentation.

I was honored to be nominated as one of the students to represent my school at the regional fair. To my great surprise, my project earned the highest score and I advanced to both the Massachusetts State and Regeneron International Science & Engineering Fair. I received a First Place award at the Massachusetts Science & Engineering Fair and continued a relationship with the organization by serving as an intern this past summer. After I found out that I would be moving on to the international fair, I repeated my entire experiment with 3 times as much data!

I am truly grateful for all of the opportunities that I have had through my project. I was honored to be invited to present at the Massachusetts Junior Academy of Science, where I met many inspiring students and scientists. I am excited to be a delegate to AJAS and I look forward to learning more about everyone else’s fascinating projects!