XVI International Botanical Congess
For induction of haustoria in Cuscuta japonica by the far-red light and tactile stimuli, the pre-irradiation of blue light was required. The blue light was needed an long time irradiation and 8 hours were required for the saturation of effect. The effect of blue light did not link to the haustoria formation if the blue light was not followed by far-red light. The competence for haustoria induction prepared by blue light was maintained for 2-3 hours in darkness. But, afterwards it decreased in the dark incubation and disappeared for 12 hours. The disappeared competence was recovered with irradiation of blue light for 3 hours. These results indicate that plural photoreceptors participate systematically to photo-induction of haustoria in Cuscuta japonica.