ABSTRACT

There are 350,000 plant species in the world, and about 80,000 are edible for humans. However, at present only about 150 species are actively cultivated, directly for human food or as feed for animals, and from these 30 produce 95% of human calories and proteins (Füleky 2009), whereby only three of them, namely rice, maize, and wheat, contribute nearly 60% of calories and proteins obtained by humans from plants (FAO 2004). Besides the adverse impacts of toxic metals on the morphological and biochemical processes of crops, manifested in undesirably reduced yield, accumulation of toxic metals in edible parts of crops could also seriously threaten human health. Consequently, the gradual increase in the contamination of the environment with toxic metals or their nanoforms due to anthropogenic activities represents a risk when providing safe, sustainable, and healthy food for a growing world population, because metals present in bioavailable forms and at excessive levels are phytotoxic (Nasreddine and Parent-Massin 2002; Reeves and Chaney 2008; Antisari et al. 2015; Khan et al. 2015; Clemens and Ma 2016; Zhou et al. 2016a). Thus, in the interest of better food safety, it is important to reduce toxic element accumulation in crops. This could be achieved by the remediation of polluted metal soils using metal tolerant plants, including some fast-growing woody plants that are able to uptake metal contaminants 480from soil and translocate them to harvestable plant parts (e.g., (Masarovičová, Kráľová, 2017, 2018)).