Figure 2.

Simplified cross talk diagram showing the effects of and interactions between plant hormones in the regulation of hypocotyl development. The effect of the plant hormones on elongation and their interactions often differ between light and darkness. The hormonal cross talk is less well established in darkness compared with light. Ethylene plays an important role in the regulation of hypocotyl development, in the light and presumably also in darkness, interacting with other plant hormones. Red arrows indicate inhibitory effects, whereas green arrows indicate stimulatory effects.