Silicon promotes seedling growth and alters endogenous IAA, GA₃ and ABA concentrations in <i>Glycyrrhiza uralensis</i> under 100 mM NaCl stress

Abstract

A sand culture experiment was conducted to determine the effects of Si on the growth and endogenous hormone concentrations (indole-3-acetic acid [IAA], gibberellic acid [GA3], and abscisic acid [ABA]) in Glycyrrhiza uralensis seedlings under 100 mM NaCl stress. Si time-dependently improved the growth and increased the biomass of seedlings, and the effect was greater at 20 days than that at 10 days after Si treatment. The effects of Si on the growth parameters and biomass were dependent on Si concentration, that is, these parameters increased with increasing Si concentration. Si also increased the levels of endogenous hormones in G. uralensis seedlings in a concentration-dependent manner. The effects on IAA and GA3 increased with increasing Si concentrations, and the effect on ABA was higher at 2 mM Si than that at the other Si concentrations. Furthermore, the effects of Si on IAA and GA3 were greater at 10 days than those at 20 days after the treatment, whereas the effect on ABA was greater at 20 days than that at 10 days after the treatment. Hence, Si can regulate the concentrations of endogenous hormones and correspondingly improve the growth of G. uralensis seedlings under salt stress condition.