2.2. Effect of the YCZ-series on the Bending Angle of the Lamina Joint of the Rice
To further confirm the inhibitory effects of the YCZ-series on BR biosynthesis in rice seedlings,
the small bending angle of the lamina joint, which is specifically affected in BR-deficient rice plants,
was measured. The test compounds were added to the culture medium for a final concentration of
1 μM. We found that the chemical-treated rice seedlings exhibited different characteristics with regard
to the bending angle of the lamina joint of rice plants. As shown in Figure 3, the bending angle of the
lamina joint of the untreated control was approximately 58.1 ± 7.9 degrees, whereas the bending angle
of the lamina joint in the chemical-treated rice plants was reduced to different degrees. With the
exception of compounds 3 and 9, the ability of the treatment to reduce the bending angle of the lamina
joint was correlated with the reduced plant height of the rice seedlings. Among the test compounds,
compound 1 was the most potent inhibitor for reducing the bending angle of the lamina joint, resulting
in a bending angle of approximately 26.3 ± 6.0 degrees.