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The Effect of Environmental Contamination on Quality of Leafy Vegetables
Jančíková, Silvie ; Pavlíková, Daniela (advisor) ; Veronika, Veronika (referee)
Heavy metals are widely distributed throughout the environment, but environment can be contaminated by these elements originated from anthropogenic activities. These toxic elements can be taken up by plant. Heavy metals accumulation and their uptake by plants depend on plant species, plant growing period, part of plant, soil characteristics (content of organic matters, physical chemical properties), interactions between metals etc. High concentrations of metal ions in plants can result in metabolic stress and so the plant metabolic stress mechanism can be induced : organic acids exudation, heavy metals binding in cell walls, phytochelatins synthesis etc.
In case, that various protective mechanisms against toxic elements are not successful, heavy metals cause the damage to plant metabolism. This is indicated by changes in the contents of amino acids and fatty acids, enzymatic changes, inhibition of yield of aboveground biomass, chlorosis of leaves.
There is an important difference between Zn and the other elements. Zn is an essential micronutrient and its content in contrast to the other elements without biological function is less toxic for plants.
Vegetables are rich sources of essentials nutrients and heavy metals can significantly affect their quality. The consumption of contaminated vegetables may result in negative effects on nutritional composition. Leafy vegetables have relatively higher concentrations and transfer factors of heavy metals in contrast to root and fruit vegetables. There is the high health risk to consume the vegetable which is exposure to heavy metal polluted environment.
The majority of European agricultural soils is safe for food production, but the areas with the high population density (China) have level of contamination which present ecological and health risk. For this reason many studies have focused on crop accumulation of heavy metals in such areas.
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