Nickel is an essential micronutrient for plants, which is in high concentrations toxic for most plants. Certain plants, named nickel hyperaccumulators, can accumulate this element in shoots at very high concentrations without inducing toxic effects. These plants actively take up nickel from the environment, load it into xylem, through which it is transported to the above-ground parts and then stored in metabolically inactive parts of the plant. Transport proteins involved in this process have not yet been identified. Several hypotheses have been developed as to why some heavy metals have developed hyperaccumulation of metals and what are its advantages. The most widely accepted is the defence hypothesis. Nickel hyperaccumulators are also studied for their use in soil phytoremediation contaminated with heavy metals. Nickel hyperaccumulators are potentially suitable for phytoremediation with nickel-contaminated soils because they have a great capability to absorb this heavy metal from the environment, and in addition, most of the accumulated nickel is stored in the shoots.
|
