Production of gibberellin-like substance in the embryo of barley during germination.

Embryos were excised from barley seeds, their homogenates were incubated with ficin, and their content in gibberellin-like substance was assayed by means of α-amylase-producing activity, but no gibberellin-like substance could be detected.Embryos free from endosperm which were cultured for five days produced measurable amounts of gibberellin-like substance. This substance was not produced when a carbon source was absent from the medium, or when air was removed after 2 days of aerobic culture. CCC and Phosfon D (at the concentration of 2×10(-4) M and 0.8×10(-4) M, respectively) inhibited the formation of the gibberellin-like substance in cultured embryos without affecting their growth.Mevalonic acid could be used as a carbon source in the culture of the embryos. The formation of the gibberellin-like substance was in this case inhibited by 0.8×10(-4) M Phosfon D, but was not inhibited by 2×10(-3) M CCC.