Date of Award

Spring 2023

Thesis Type

Open Access

Degree Name

Honors Bachelor of Arts




Dr. Paul Stephenson

Committee Member

Dr. Kasandra Riley

Committee Member

Dr. Kathryn Sutherland


Soil salinity, an abiotic stressor associated with climate change effects, inhibits the normal growth and development of sensitive crop species. The excessive accumulation of salt ions in plant tissue induces oxidative stress, which is characterized by an increased production of reactive oxygen species (ROS) damaging plant organelles and disrupting normal metabolic functions. Seaweed extracts (SWE) may be a solution for mitigating the effects of salt stress on crop yield and quality, as they introduce bioactive ingredients that are able to regulate gene expression and enhance natural physiological processes in plants. However, the positive benefits of SWE applications differ between plant species, and further research is required before the biostimulant is incorporated into agricultural practices. Some crop varieties of soybeans (Glycine max) have been identified to possess stress-responsive genes, like GmSALT3, that are linked to salt tolerance through increased activity in the antioxidant enzymatic system responsible for scavenging ROS. This study aims to compare the effect of Ascophyllum nodosum derived SWE on an identified salt tolerant soybean variety (Manokin) and an identified salt sensitive soybean variety (Clark) exposed to salt stress. The negative effects of salt stress on physical growth, especially root anatomy, were slightly ameliorated by the SWE. However, peroxidase (POD) activity assessments showed that the SWE did not stimulate a defensive antioxidant response in the Clark seedlings lacking the critical function of GmSALT3. POD activity for SWE treated Manokin seedlings under salt stress remained constant relative to the control, indicating that the activity of the other antioxidant enzymes, superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT), involved in the ROS detoxification process must be further assessed to determine the effect on salt tolerant soybean varieties.

Rights Holder

Elena Hoang

Available for download on Monday, January 06, 2025