Photomorphogenesis in Pteris vittata II. Recovery from blue-light-induced inhibition of spore germination

1. 1. In the fern Pteris vittata, low-energy blue-light-inducedinhibition of phytochrome-dependent spore germination and darkrecovery from this inhibition were repeatedly observed severaltimes at intervals of 3 days at 26. The same amount of incidentenergy of blue light was required for inhibition in each successivetreatment.
2. 2. The recovery from blue-light-induced inhibitionof germinationwas markedly accelerated by continuous illuminationwith redlight, and this red light effect was not affected bythe presenceof CMU.
3. 3. The recovery process was not influencedby a single exposureto redlight, but was definitely promotedby brief red irradiationsgiven intermittently, at least 2 times,at equal intervals duringthe first 8 hr after blue light treatment.The effect of intermittentlygiven red light was annulled wheneach red exposure was followedby brief far-red irradiation.These facts suggest that phytochromemay be involved in therestoration of the ability of sporesto germinate (in responseto red light) which had been lostby blue irradiation.

¹Present address: Botany Department, Faculty of Science, Universityof Tokyo, Hongo, Tokyo 113.