Effect of auxinhormone lanthanide complexes on the growth of wheat coleoptile.

Naphthalene-1-acetic acid (HNAA), dichlorophenoxy acetic acid (HDAA), and indole-3-acetic acid (HIAA) are auxinhormones that can affect the growth of plants. The lanthanide complexes of the above auxinhormone LnA3 x 3H2O (Ln = La3+, Ce3+, Sm3+, Er3+, Yb3+; HA = HNAA, HDAA, HIAA; A = NAA-, DAA-, IAA-) were synthesized and are characterized in this paper. The solubility and IR spectra of these complexes were also studied. Experiments of the effects of LnCl3 x nH2O, HA, and LnA3 x 3H2O on the growth rate of wheat coleoptile sections show, that LnCl3 x nH2O promotes the growth of wheat coleoptile when this compounds concentration is lower than 2 x 10(-5) M and the promotion is very significant when the concentration of Ln3+ is lower than 8 x 10(-6) M. It was also found that the effect of LnA3 x 3H2O on the growth of wheat coleoptile is stronger than that of LnCl3 x nH2O and HA, which indicates that the combination of Ln3+ with HA act synergistically.