Der Einfluss hellroter und dunkelroter Strahlung auf die geotropische Reaktion der Keimlinge vonSinapis alba L

Summary

Our experiments indicate that the negative geotropic reactivity of dark-grown mustard seedlings (Sinapis alba L.) is greatly increased when the seedlings are irradiated with visible light. Obviously in irradiated seedlings the geotropic reaction is more rapid and intense. The results of this paper point out that light controls the geotropic behaviour in exactly the same way as morphogenesis. Apparently the increased geotropic reactivity of the irradiated seedlings is only one manifestation of the basic metabolic changes which occur in the dark-grown seedling after the absorption of light and which finally lead to photomorphogenesis.

In earlier papers we have been able to show that photomorphogenesis in these mustard seedlings is controlled by two basic photoreactive systems: the reversible red far — red system and the so called blue far — red system. The same, probably, is true for the control of the geotropic reactivity under our standard experimental conditions.