Effects of Exogenous Application of Indole-3-Butyric Acid on Maize Plants Cultivated in the Presence or Absence of Cadmium.

Auxins are plant hormones that affect plant growth, development, and improve a plant's tolerance to stress. In this study, we found that the application of indole-3-butyric acid (IBA) had diverse effects on the growth of maize ( L.) roots treated without/with Cd. IBA caused changes in the growth and morphology of the roots under non-stress conditions; hence, we were able to select two concentrations of IBA (10 M as stimulatory and 10 M as inhibitory). IBA in stimulatory concentration did not affect the concentration of HO or the activity of antioxidant enzymes while IBA in inhibitory concentration increased only the concentration of HO (40.6%). The application of IBA also affected the concentrations of mineral nutrients. IBA in stimulatory concentration increased the concentration of N, K, Ca, S, and Zn (5.8-14.8%) and in inhibitory concentration decreased concentration of P, K, Ca, S, Fe, Mn, Zn, and Cu (5.5-36.6%). Moreover, IBA in the concentration 10 M had the most positive effects on the plants cultivated with Cd. It decreased the concentration of HO (34.3%), the activity of antioxidant enzymes (23.7-36.4%), and increased the concentration of all followed elements, except Mg (5.5-34.1%), when compared to the Cd.