Reproduction induced by blue light in female gametophytes of Laminaria saccharina.

In red light at 15°C, female gametophytes of Laminaria saccharina continue to grow indefinitely without becoming fertile, but 6-12 hours' irradiation with blue light induces the production of eggs. At lower temperatures, some gametophytes become fertile in red light, but blue irradiation increases the percentage of fertile gametophytes.