Exogenous auxin type compounds amend PEG-induced physiological responses of pea plants

Drought is among the abiotic stresses, which considerably decrease the agricultural production worldwide. The effects of exogenous auxin-type compounds 1-[2-chloroethoxycarbonyl-methyl]-4-naphthalenesulfonic acid calcium salt (TA-12) and 1-[2-dimethylaminoethoxicarbonylmethyl]naphthalene chlormethylate (TA-14) on drought stress responses induced by polyethylene glycol-6000 (PEG) in garden pea (Pisum sativum L.) plants were investigated. Preliminary application of TA compounds partially restored the normal growth of PEG-treated plants, led to less accumulation of proline, phenolic compounds and low-molecular thiols and did not provoke malondialdehyde buildup. The pea plants pretreated with auxin-type compounds displayed reduction in hydrogen peroxide content and consequently lower oxidative stress levels. This was confirmed by a decrease of the activity of the antioxidant enzymes superoxide dismutase, catalase, and guaiacol peroxidase. Taken together these results showed that the preliminary application of TA-12 and TA-14 reduced the negative effects of drought stress in pea plants.