Date of Award

Spring 2024

Thesis Type

Open Access

Degree Name

Honors Bachelor of Arts

Department

Physics

Sponsor

Anne E. Murdaugh

Committee Member

Samantha Fonseca

Committee Member

Paul Stephenson

Abstract

This study investigates the effects of sodium ion (Na+) concentration on the adhesion of Brassica Rapa root hairs using atomic force microscopy (AFM). Plant root hair adhesion to soil particles plays a crucial role in anchoring plants and facilitating nutrient uptake. Previous research has shown that calcium ions (Ca2+) cross-link pectin molecules in the cell wall, increasing rigidity and reducing adhesion. As Na+ binds to pectin without cross-linking, we expected that root hairs exposed to sodium chloride (NaCl) solutions would exhibit longer adhesive interactions and similar binding forces compared to those exposed to calcium chloride (CaCl2) solutions of equal concentrations. Brassica Rapa plants were grown, and their root hairs were exposed to environmentally relevant NaCl concentrations (0.1, 1, 10, and 100 mM). AFM was used to quantify the adhesion by measuring pull-off forces and distances. The results showed that while the number of adhesive events was not significantly higher in NaCl compared to CaCl2, root hairs in NaCl exhibited longer pull-off distances. Binding forces were similar in NaCl and CaCl2 at lower concentrations (0.1, 1, and 10 mM), but significantly reduced in 100 mM NaCl. These findings suggest that high Na+ concentrations disrupt the binding mechanism of root hairs to soil particles, potentially impacting plant nutrient uptake and health in saline environments. Understanding the factors influencing root hair adhesion contributes to the development of strategies for optimizing plant performance in challenging soil conditions.

Rights Holder

Natasha Mulenga

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Available for download on Tuesday, May 13, 2025

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