GENETICAL MODIFICATIONS OF PLANTS TO INCREASE ACCUMULATION OF HEAVY METALS

Phytoremediation is method which uses plants for absorption, accumulation and degradation of pollutants in the environment Heavy metals present in soil or water are not degraded in comparison to organic contaminants This is the reason, why the high efficiency of absorption and accumulation of heavy metals is required in shoots of these plants There are plants naturally accumulating metals in high concentration on heavy metals contaminated soil in the nature called hyperaccumulators Mostly these plants are small create small amount of biomass and therefore they are not exploitable for phytoremediation However the recognition of their mechanisms of heavy metal detoxification allows the preparation of transgenic plants which growth quickly accumulate heavy metals in shoots and simultaneously create enough of biomass The sulphur-rich compounds participate in detoxification of heavy metals in plants Overexpression of these compounds leads to the fact that heavy metals in plants are binded and transported to vacuole The uptake of heavy metals can be enhanced by expression of membrane transporters Many plants with the ability to accumulate heavy metals were prepared by these approaches These plants could be the alternative to usual physico chemical methods which are very expensive