Assessment of synthetic auxin type compounds as potential modulators of herbicide action inPisum sativumL.

The physiological effects of the synthetic auxins 1-[2-chloroethoxycarbonyl-methyl]-4-naphthalenesulfonic acid calcium salt (TA-12) and 1-[2-dimethylaminoethoxicarbonylmethyl]naphthalene chlormethylate (TA-14) on herbicide-induced responses in pea (Pisum sativumL.) seedlings were studied. Two different herbicides inhibiting amino acid biosynthesis namely Glyphosate and Glean-75 were used in this study. The herbicide treatments provoked metabolic disruption and consequently led to inhibition of plant growth. Pretreatment with the synthetic auxins partially improved the growth of herbicide-treated plants. This was accompanied by a decrease of non-enzymatic antioxidants (free proline, low-molecular thiols, and total phenolics), malondialdehyde, hydrogen peroxide and superoxide dismutase activity. Glutathione reductase activity was increased by the herbicide treatments, but was not altered by the TAs. The pretreatment with the auxin compounds modulated the activities of catalase, guaiacol peroxidase, and glutathione-S-transferase in specific manner and the plants were able to cope with the negative consequences of the herbicides and to sustain their growth.