Plant Growth Regulators and Improvements in Phytoremediation Process Efficiency: Studies on Metal Contaminated Soils

Plant growth regulators (PGRs) are organic compounds that in small amounts alter the growth of a plant or plant part. The term PGR includes naturally occurring plant growth substances, phytohormones, as well as synthetic compounds or chemical analogies. PGRs affect flowering, aging, root growth, distortion and killing of leaves, stems, and other parts, prevention or promotion of stem elongation, color enhancement of fruit, prevention of leafing and/or leaf fall, among others. PGRs could benefit phytoremediation in various ways, increasing the efficiency of a selected "depolluting plant." As an example, it is deliverable for a "depolluting plant" (1) to increase survival and development in stressful conditions; contaminated sites are often quite poor in fertility regarding soil structure and nutrient content. (2) To increase tolerance to toxic effects of different contaminants (organics and/or inorganics) at the level of concentration present in contaminated media. (3) To increase the rate of contaminant treatment (increasing degradation of organics, or increasing biomass production and metal uptake, and accumulation in the upper plant in case of inorganics).