3.5.4. Changes in Endogenous GA3

The GA3 content in the treatment groups presented a sustained decreasing trend, while that in the control group showed a slight decreasing trend (Figure 4D). In the initiation period, the GA3 content in the treatment groups was higher than that in the control group, suggesting that ABT-1 treatment could effectively enhance GA3 synthesis. During the callus formation period, the GA3 content in the control group and the treatment groups decreased in various degrees, and the highest GA3 content (3.9 ng·g−1) was observed in ABT-1— 500 mg·L<sup>−</sup>1, while the control group had a GA3 content of merely 1.4 ng·g−1. During the adventitious root formation and elongation period, the GA3 content in ABT-1—500 mg·L−<sup>1</sup> was the lowest at 1.1 ng·g<sup>−</sup>1, probably due to the consumption of large amounts of GA3 for the formation of adventitious roots in cuttings at this stage.
