Effects of Auxin-Type Plant Growth Regulators and Cold Stress on the Endogenous Polyamines in Pea Plants

The effect of pre-application of structural auxin analogues TA-12 (1-[2-chloroethoxycarbonyl-methyl]-4-naphthalenesulfonic acid calcium salt) and TA-14 (1-[2-dimethylaminoethoxicarbonylmethyl] naphthalenechlormethylate) on biochemical parameters of pea (Pisum sativum L. cv. Jablo) plants subjected to low temperature (LT, -1 degrees C, for 24h) was studied. For the first time the effects of these auxin analogues, applied with or without LT were investigated on the endogenous polyamine (PA) content. The LT treatment increased free and bound putrescine (Put) and spermine (Spm), conjugated and bound spermidine (Spd), accompanied by a decrease in conjugated Put and Spm, and free Spd. Stress biomarkers hydrogen peroxide (H2O2) and malondialdehyde (MDA) as well as proline were augmented by LT treatment. The TAs application decreased conjugated polyamines (Put, Spm and Spd), free Spd, H2O2 and MDA but increased bound Spm and proline in pea plants. The application of TAs before LT lessened the alterations in PAs (mainly in free and bound fractions) and stress biomarkers content caused by LT, and enhanced conjugated Spd and phenolics, which contributed to increased plant cold tolerance.

Automated summary

The effect of pre-application of structural auxin analogues TA-12 and TA-14 on biochemical parameters of pea plants subjected to low temperature was investigated. The study showed that the application of TA analogues decreased conjugated polyamines, free spermidine, hydrogen peroxide, and malondialdehyde while increasing bound spermine and proline content in pea plants. Pre-treatment with TA analogues reduced the alterations in polyamines and stress biomarkers caused by low temperature and enhanced plant cold tolerance.