ORIGINAL ABSTRACT

Spray drift and runoff are the main factors responsible for the diffuse environmental contamination caused by glyphosate, the active ingredient in the most widely marketed herbicides worldwide. Although the toxicity of glyphosate to non-target organisms has been demonstrated, little attention has been given to the indirect harm caused to their offspring, especially considering ferns. We evaluated the adverse effects of glyphosate-based herbicide on the growth and metabolism of individuals of the aquatic fern Regnellidium diphyllum and their progeny. Morphometric attributes and shikimic acid levels were quantified after exposure to five doses of glyphosate (1.34, 3.35, 6.70, 10.05, 13.40 mg L− 1) in: (G1) plants derived from spore germination, and (G2) plants derived from vegetative propagation. Offspring from G2 plants were assessed for morphometric traits. G1 and G2 plants exhibited fewer leaves, shorter petioles, reduced leaf span (from the recommended application dose in G1: 1.34 mg L− 1), and increased shikimic acid production (from twice the recommended dose: 3.35 mg L− 1) compared to the control (plants not exposed to glyphosate). Only spores from G2 plants exposed to the lowest glyphosate concentration and the control were able to germinate in commercial substrate. The offspring of G2 plants showed lower values for morphometric attributes and did not grow over a 30-day period, unlike control plants. These findings highlight the threat posed by current agricultural practices to the establishment and renewal of populations of this non-target species and underscore the need for alternative strategies and effective monitoring of pesticide application to minimize their impacts on ecosystems.