It was found that treatment of Neopyropia yezoensis gametophyte with 1-aminocyclopropanecarboxylic
acid (ACC), a precursor of ethylene that is one of the plant hormones in land
plants, promotes sexual reproduction. On the other hand, when the same
experiment was conducted with ethephon, which is an ethylene generator, the
promotion of sexual reproduction, observed with ACC treatment, was absent.
Therefore, it was clarified that ethylene, which is known to control fruit
maturation, does not act on Neopyropia
yezoensis, and its precursor acts as a plant hormone.