The influence of IAA and TIBA on iron concentration of maize seedlings

Abstract

The effects of IAA and TIBA treatment on the iron concentration were studied in nutrient solution (with and without Fe) at 14 days old maize seedlings (Zea mays cvs.Norma SC)

The IAA treatment was applied at 7 and 9 days after germination as droplets to the second and third leaf-peak, and before taking the root-washings as leaf spray. Maize seedlings also were treated with TIBA at both (+Fe and −Fe) groups. The TIBA was given in Lanolin to the mesocotyl as a “ring”, and before spraying the leaf with IAA in a form of drop to the leaf base.

The treatment with IAA decreased the iron concentration in the shoots and in the roots of +Fe precultured plants and increased it in −Fe precultured plants. The treatment with TIBA retards the shoot-to-root transport of IAA. When the seedlings were treated with IAA and TIBA, higher iron concentrations were observed in the shoots and in the roots of maize seedlings.

The iron concentration is significantly higher in the shoots of maize seedlings infected by smut-gall tumour (Ustilago. maydis Cda.) when TIBA treatment was applied. We found extremely high iron concentration in the roots of infected seedling, causing serious damage to the roots, probably due to the production of free radicals as consequence of the high iron content.

The results demonstrate that IAA plays a role in the shoot to root communication.