Hormesis in Plants: Implications for Weed Management and Crop Production

Authors

• Luka Milosevic, University of Nebraska-LincolnFollow

First Advisor

Stevan Knezevic

Degree Name

Doctor of Philosophy (Ph.D.)

Committee Members

Amit Jhala, George Gogos, Sam Wortman, Tala Awada

Department

Agronomy

Date of this Version

5-4-2026

Document Type

Dissertation

Citation

A dissertation presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree Doctor of Philosophy

Major: Agronomy

Under the supervision of Professor Stevan Knezevic

Lincoln, Nebraska, May 2026

Comments

Copyright 2026, Luka Milosevic. Used by permission

Abstract

Hormesis is a biphasic toxicological phenomenon in which low doses of a stressor stimulate biological performance of an organism, while higher doses inhibit it. In plants, hormesis has been documented following exposure to various environmental stressors, including herbicides, pollutants, and thermal stress. However, the physiological basis of hormesis and its implications for crop production and weed management remain poorly understood. Thus, the objective of this dissertation was to investigate hormetic responses in plants and evaluate their agronomic significance for crops and weeds using representative model species. A combination of field and controlled-environment experiments was conducted to quantify plant responses to sublethal stress exposure using nonlinear dose-response modeling approaches. Field studies evaluated soybean responses to sublethal doses of glyphosate and dicamba, including scenarios relevant to herbicide drift events, as well as soybean responses to thermal stress associated with flame weeding performed during reproductive stages. Growth, biomass accumulation, physiological traits, and yield responses were assessed to determine whether stimulatory effects were associated with improved plant function or productivity. Greenhouse experiments examined the growth and physiological responses of Ipomoea hederacea (L.) Jacq. (ivyleaf morningglory) to glyphosate and dicamba across a wide dose range. Results demonstrated that sublethal glyphosate doses can induce hormetic stimulation in several plant traits. In soybean, sublethal glyphosate doses increased aboveground biomass under field conditions, yet this stimulation was not associated with improved physiological performance or yield. Conversely, exposure of soybean to low dicamba doses caused measurable injury and decline in all responses but did not induce consistent evidence of hormetic stimulation. Similarly, ivyleaf morningglory exhibited pronounced hormetic responses following sublethal glyphosate exposure. Findings demonstrate that hormesis can influence plant growth and competitive interactions in agricultural systems but is highly variable among species, stressors, doses, environmental conditions, and physiological responses. Recognizing and understanding hormetic responses is therefore critical for optimizing crop production and herbicide use, minimizing unintended crop injury or weed stimulation, and improving integrated weed management strategies.

Recommended Citation

Milosevic, Luka, "Hormesis in Plants: Implications for Weed Management and Crop Production" (2026). Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–. 489.
https://digitalcommons.unl.edu/dissunl/489