[Light regulation of the formation of antheridia in Polypodium crassifolium L. (Pessopteris crassifolia Underw. and Maxon)].

In Polypodium crassifolium, light controls the induction of antheridium formation in contrast to hormonal induction in other fern species.Antheridium formation is caused by an exposure to darkness or far-red. The minimum duration of this treatment required to bring about antheridium formation depends on the length of preillumination with white light.Red light interruptions of 5 min (6,6 μE cm(-2) sec(-1)) at 24 h intervals applied during the whole dark period extinguish antheridium induction. Red light inhibition is cancelled by a succeeding irradiation with far-red.Inhibitors of protein and nucleic acid synthesis do not block antheridium induction. Actinomycin-D inhibits the formation of spermatogenic tissue.The results presented indicate a control of antheridium formation in Polypodium crassifolium via a "negative" photoresponse (MOHR, 1966). So ist appears highly improbable that this differentiation process is based on a specific gene activation in the sense of JACOB and MONOD.