[Changes in gibberellin-like substances of lettuce seeds after light exposure].

The contents of gibberellin-like substances in lettuce seeds were determined. In darkness the seeds contain only small amounts of gibberellin-like substances, but upon illumination with near red light there is a sharp increase in the gibberellin content within one hour. It is concluded that lettuce seeds in darkness do not contain the amounts of gibberellin necessary for germination and that under the influence of light these amounts are provided.