Physiological response of crop plants to the endocrine-disrupting chemical nonylphenol in the soil environment

Abstract

Nonylphenols are endocrine-disrupting chemicals that are used in various industries and are constantly discharged into the terrestrial environment. However, there have been few studies on the phytotoxicity of this chemical in the soil environment. In this study, mung bean (Vigna radiata) and rice (Oryza sativa) were grown in soil containing nonylphenol for 14 and 21 days (reflecting acute and chronic exposure, respectively), and we evaluated physiological responses (chlorophyll content, photosynthetic activity, and stomatal opening size) as well as changes in plant growth (shoot growth and root development) in crop plants grown in soil containing nonylphenol. In mung bean, chlorophyll content and stomata size decreased by exposure to nonylphenol. The decrease in chlorophyll content was attributed to electrolyte leakage due to damage of membrane barrier with increase of cell permeability caused by nonylphenol. Moreover, necrosis of the leaves of mung bean was observed at 2000 mg/kg soil. In rice, shoot growth, chlorophyll content and root development were reduced by chronic exposure to nonylphenol at 2000 mg/kg. Although the exposure concentrations were higher and nonylphenols are non-persistent, their constant release into soil poses a risk to terrestrial ecosystems. Our findings provide information that can be useful for soil ecological risk assessment for nonylphenol in agricultural practices.