3.4.4. Changes in Endogenous GA3

As indicated by Figure 3D, for the treatment groups and the control group, the contents of GA3 exhibited a continuous decrease over time. During the initiation period, the GA3 content of ABT-1—1000 mg·L−<sup>1</sup> reached the highest level, namely 7.0 ng·g<sup>−</sup>1. After callus formation, the GA3 content of both treatment and control groups decreased, with that of treatment groups decreasing obviously, possibly due to the high demand for GA3 in the growth of root primordia [24]. During the adventitious root formation and elongation period, the GA3 contents of treatment groups were again observed as decreasing, but there was no obvious change in the GA3 content of the control group. At this point, adventitious roots were formed. As the root tip emerged from the skin pore, the GA3 content gradually decreased, probably because high concentrations of GA3 inhibited its elongation growth.
