Figure 6.

Diagram summarizing the two proposed GA-signaling pathways in rice. (Model A) Gα works in high sensitive GA receptor system. There may be an alternative GA receptor system for low sensitivity to GA that does not involve Gα. High sensitive α-amylase induction and internode elongation by GA may be mediated mainly through the high sensitive reception system (red), whereas leaf sheath elongation may be through the low sensitive reception system (blue). (Model B) Gα works in a pathway that regulates the GA signaling. α-Amylase induction and internode elongation may be regulated mainly by this pathway to result in high sensitivities to GA (red), whereas leaf sheath elongation may be not regulated by this pathway to result in low sensitivity to GA (blue). The SLR protein works at the downstream site of these two pathways.