Fungicides influence pseudoephedrine bioaccumulation and stress response in Cucurbita pepo

Abstract

Pharmaceuticals in agricultural soils are emerging contaminants, yet their interactions with edible crops remain poorly understood. This study examined the uptake, translocation, and physiological effects of pseudoephedrine (PSE) in Cucurbita pepo cv. Atena Polka and the influence of co-applied fungicides (benomyl, B; chlorothalonil, D). Plants were grown for 28 days in soil spiked with 1 mg kg −1 PSE alone or combined with B or D. PSE concentrations in plant tissues, bioaccumulation (BAF), and root-to-leaf translocation factors (TF) were determined, along with major latex-like protein ( MLP ) gene expression, antioxidant responses, and oxidative damage. The highest PSE concentrations occurred in stems (7.89 µg g −1 ), followed by roots (4.18 µg g −1 ), with limited leaf translocation (0.42 µg g −1 ; TF = 0.10). Benomyl (B) increased root (5.56 µg g −1 ) and leaf (1.33 µg g −1 ) concentrations, whereas chlorothalonil (D) reduced root (3.10 µg g −1 ) and leaf (0.38 µg g −1 ) levels while leaving stem concentrations unchanged. MLP expression followed similar trends: it was downregulated by PSE, strongly upregulated by PSE + B, and restored near control levels by PSE + D. Plant biomass remained unaffected. PSE alone induced moderate antioxidant responses, while PSE + B was associated with stronger oxidative stress responses; in contrast, PSE + D did not significantly affect glutathione S-transferase (GST), ascorbate peroxidase (APX), or guaiacol peroxidase (POX) activities and maintained membrane integrity. Fungicides differentially influence PSE uptake, translocation, and plant stress responses illustrating complex interactions between pharmaceuticals, agrochemicals, and crops with implications for phytoremediation and food safety.