The Tensile Root Strength of Spartina patens Varies with Soil Texture and Atrazine Concentration

Abstract

The widely used agricultural herbicide atrazine enters wetlands and may potentially affect wetland plants that provide critical reinforcement of soil strength and contribute to ecosystem stability in ways that may vary among soil types. We conducted greenhouse experiments using four levels of atrazine doses and three different soil textures to test for differences between control and experimental treatments and interactive effects of soil texture and atrazine exposure by using the tensile root strength of the coastal wetland emergent macrophyte Spartina patens as the response variable. The tensile root strength of S. patens was not affected after 50 days of atrazine exposure in an organic soil, but was 29–55% lower vs. controls in a 204-day experiment in sand-, clay-, and organic-dominated soil textures after atrazine exposure with the greatest decline in the sand-atrazine treatment. But there was no statistically significant difference in the distribution of the tensile root strength data of the main effects from individual treatments compared with the soil texture and atrazine combination treatments or any difference in the magnitude of the tensile root strength means. These results indicate that there were no synergistic interactive effects of soil texture and atrazine exposure on S. patens tensile root strength. However, the biogeochemical characteristics of soil texture may play an important role in the plant absorption of xenobiotics.