The influence of ammonium nitrate, pH and indole butyric acid on root induction and survival in soil of micropropagated Eucalyptus globulus

Abstract

Rooting of Eucalyptus globulus shoots was influenced by the concentration of the indole butyric acid (IBA) and NH4+ in the root-induction medium. Optimum plantlet vigor and survival were achieved using low concentrations (1 - 2.5 μM) of IBA and when NH4NO3 was removed. Removal of NH4+ also had a significant effect on medium pH, its presence caused a decrease in pH as the culture period proceeded. When different nitrate compounds (excluding NH4NO 3) were used as the nitrogen source, the medium pH was more stable and this was associated with higher root production. The higher root production, in association with appropriate IBA concentrations, produced plantlets with higher survival and better growth on transfer to soil.