title: Foliar heavy metal uptake, toxicity and detoxification in plants: A comparison of foliar and root metal uptake.
abstract: Anthropologic activities have transformed global biogeochemical cycling of heavy metals by emitting considerable quantities of these metals into the atmosphere from diverse sources. In spite of substantial and progressive developments in industrial processes and techniques to reduce environmental emissions, atmospheric contamination by toxic heavy metals and associated ecological and health risks are still newsworthy. Atmospheric heavy metals may be absorbed via foliar organs of plants after wet or dry deposition of atmospheric fallouts on plant canopy. Unlike root metal transfer, which has been largely studied, little is known about heavy metal uptake by plant leaves from the atmosphere. To the best of our understanding, significant research gaps exist regarding foliar heavy metal uptake. This is the first review regarding biogeochemical behaviour of heavy metals in atmosphere-plant system. The review summarizes the mechanisms involved in foliar heavy metal uptake, transfer, compartmentation, toxicity and in plant detoxification. We have described the biological and environmental factors that affect foliar uptake of heavy metals and compared the biogeochemical behaviour (uptake, translocation, compartmentation, toxicity and detoxification) of heavy metals for root and foliar uptake. The possible health risks associated with the consumption of heavy metal-laced food are also discussed.
authors.affiliation: Department of Environmental Sciences, COMSATS Institute of Information Technology, Vehari, 61100, Pakistan.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Shahid
authors.affiliation: Centre d'Etude et de Recherche Travail Organisation Pouvoir (CERTOP), UMR5044, Université J. Jaurès - Toulouse II, 5 Allée Antonio Machado, 31058 Toulouse Cedex 9, France. Electronic address: camille.dumat@ensat.fr.
authors.forename: Camille
authors.initials: C
authors.lastname: Dumat
authors.affiliation: Department of Environmental Sciences, COMSATS Institute of Information Technology, Vehari, 61100, Pakistan.
authors.forename: Sana
authors.initials: S
authors.lastname: Khalid
authors.affiliation: Centre d'Etude et de Recherche Travail Organisation Pouvoir (CERTOP), UMR5044, Université J. Jaurès - Toulouse II, 5 Allée Antonio Machado, 31058 Toulouse Cedex 9, France; Géosciences Environnement Toulouse (GET), Observatoire Midi Pyrénées, Université de Toulouse CNRS, IRD, 14 avenue E. Belin, F-31400 Toulouse, France.
authors.forename: Eva
authors.initials: E
authors.lastname: Schreck
authors.affiliation: School of Life Science, South China Normal University, No. 55 Zhongshan Avenue West Guangzhou 510631, PR China.
authors.forename: Tiantian
authors.initials: T
authors.lastname: Xiong
authors.affiliation: Institute of Soil and Environmental Sciences, University of Agriculture Faisalabad, Faisalabad 38040, Pakistan; MARUM and Department of Geosciences, University of Bremen, Bremen D-28359, Germany; Southern Cross GeoScience, Southern Cross University, Lismore 2480, NSW, Australia.
authors.forename: Nabeel Khan
authors.initials: NK
authors.lastname: Niazi
mesh_terms: D000327:Adsorption; D001272:Atmosphere; D004784:Environmental Monitoring; D004787:Environmental Pollution; D008658:Inactivation, Metabolic; D008011:Lichens / Q000737:chemistry; D019216:Metals, Heavy / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D010944:Plants / Q000378:metabolism*; D018570:Risk Assessment; D012989:Soil Pollutants / Q000378:metabolism*
chemical_list: D019216:Metals, Heavy; D012989:Soil Pollutants
keywords: Atmospheric pollution; Detoxification; Foliar uptake; Heavy metals; Root uptake; Toxicity