Copper oxide nanoparticle foliar uptake, phytotoxicity, and consequences for sustainable urban agriculture
Résumé
Throughout the world, urban agriculture supplies fresh local vegetables to city populations. However, the increasing anthropogenic uses of metal-containing nanoparticles (NPs) such as CuO-NPs in urban areas may contaminate vegetables through foliar uptake. This study focused on the CuO-NP transfer processes in leafy edible vegetables (i.e., lettuce and cabbage) to assess their potential phytotoxicity. Vegetables were exposed via leaves for 5, 10, or 15 days to various concentrations of CuO-NPs (0, 10, or 250 mg per plant). Biomass and gas exchange values were determined in relation to the Cu uptake rate, localization, and Cu speciation within the plant tissues. High foliar Cu uptake occurred after exposure for 15 days for lettuce [3773 mg (kg of dry weight)-1] and cabbage [4448 mg (kg of dry weight)-1], along with (i) decreased plant weight, net photosynthesis level, and water content and (ii) necrotic Cu-rich areas near deformed stomata containing CuO-NPs observed by scanning electron microscopy and energy dispersive X-ray microanalysis. Analysis of the CuO-NP transfer rate (7.8-242 μg day-1), translocation of Cu from leaves to roots and Cu speciation biotransformation in leaf tissues using electron paramagnetic resonance, suggests the involvement of plant Cu regulation processes. Finally, a potential health risk associated with consumption of vegetables contaminated with CuO-NPs was highlighted.
Mots clés
Agriculture
Health risks
Histology
Magnetic resonance
Metal nanoparticles
Nanoparticles
Paramagnetic resonance
Plants (botany)
Scanning electron microscopy
Tissue
Vegetables
copper oxide nanoparticles
Energy dispersive x ray microanalysis
Metal-containing nanoparticles
Potential health risks
Regulation process
Transfer process
Transfer rates
Urban agricultures
copper oxides
copper oxide nanoparticle
Copper
Metal nanoparticle
Oxide
alternative agriculture
Biotransformation
Fertilizer application
Gas exchange
Health risk
Nanoparticle
Photosynthesis
Phytotoxicity
Speciation (chemistry)
Translocation
Urban agriculture
Water content
agriculture
Article
Biomass
Cabbage
Electron spin resonance
Energy dispersive x ray spectroscopy
Human
Leaf tissue
Lettuce
Stomatal conductance
Urban area
Vegetable
Electron probe microanalysis
Metabolism
brassica oleracea var. capitata
Lactuca
Oxides