Efficiency index as the integral indicator of Triticum aestivum response to growth regulators

In the current study we investigated the effectiveness of synthetic Thidiazuron (TDZ), Cytodef (CTD), Epin Extra (R) (24-EB) and natural Ribav-Extra (R) (RE) plant growth regulators (PGR) with a view to improving the heavy metal-tolerance in intact plants. To evaluate the effectiveness of PGR we chose the following parameters: the axial growth (as an integral indicator of the plant response to the environment), the superoxide generation (as an indicator of oxidative stress), the malondialdehyde (MDA) content (as an indicator of oxidative damage degree in plants), catalase (CAT) activity (as an indicator of the antioxidant defence systems activity) and the PGR capacity to change absorption and translocation of heavy metals in plants. The efficiency index was estimated on the basis of the results of winter wheat (Triticum aestivum L.) seedlings affected by 10 mu M or 1 mM Zn2+, Cu2+ and Ni2+ or Pb2+ heavy metals. An empirical scale of the efficiency of PGR was developed. The study found that the efficiency of the PGR investigated with respect to tolerance of heavy metals increased as follows: TDZ < CTD < RE < 24-EB.