Effects of indole-3-acetic acid (IAA) on sunflower growth and heavy metal uptake in combination with ethylene diamine disuccinic acid (EDDS)

Root and shoot growth of metal-stressed plants were most effectively increased with 10−10 M IAA, and also the extraction of both metals was significantly increased at this treatment level. IAA reduced the negative metal effects, such as reduced shoot and root dry weight, root length, root volume and root surface area. EDDS significantly decreased metal uptake by the plants, thus reducing metal stress and promoting plant growth. The combined application of IAA with EDDS significantly increased Zn uptake in comparison to EDDS only treated plants. The experiments indicate that IAA can alleviate toxic effects of Pb and Zn on plant root and shoot growth and can in combination with chelants such as EDDS increase the phytoextraction potential of these plants.