Chloroplast photo-relocation movement is crucial for plant survival; however, the mechanism of this phenome- non is still poorly understood. Especially, the signal that goes from photoreceptor to chloroplast is unknow...Chloroplast photo-relocation movement is crucial for plant survival; however, the mechanism of this phenome- non is still poorly understood. Especially, the signal that goes from photoreceptor to chloroplast is unknown, although the photoreceptors （phototropin 1 and 2） have been identified and an actin structure （chloroplast actin filaments） has been characterized that is specific for chloroplast movement. Here, in gametophytes of the fern Adiantum capillus-veneris, gametophores of the moss Physcomiterella patens, and leaves of the seed plant Arabidopsis thaliana, we sought to characterize the signaling system by measuring the lifetime of the induced response. Chloroplast movements were induced by microbeam irradiation with high-intensity blue light and recorded. The lifetime of the avoidance state was measured as a lag time between switching off the beam and the loss of avoidance behavior, and that of the accumulation state was measured as the duration of accumulation behavior following the extinction of the beam. The lifetime for the avoidance response state is approximately 3-4rain and that for the accumulation response is 19-28 rain. These data suggest that the two responses are based on distinct signals.展开更多
基金supported in part by Grants-in-Aid for scientific research from the Ministry of Education, Culture, Sports, Science, and Technology of Japan (23120523 to M. W.)the Japan Society for the Promotion of Science (20227001, 25120721, and 25251033 to M. W.)
文摘Chloroplast photo-relocation movement is crucial for plant survival; however, the mechanism of this phenome- non is still poorly understood. Especially, the signal that goes from photoreceptor to chloroplast is unknown, although the photoreceptors （phototropin 1 and 2） have been identified and an actin structure （chloroplast actin filaments） has been characterized that is specific for chloroplast movement. Here, in gametophytes of the fern Adiantum capillus-veneris, gametophores of the moss Physcomiterella patens, and leaves of the seed plant Arabidopsis thaliana, we sought to characterize the signaling system by measuring the lifetime of the induced response. Chloroplast movements were induced by microbeam irradiation with high-intensity blue light and recorded. The lifetime of the avoidance state was measured as a lag time between switching off the beam and the loss of avoidance behavior, and that of the accumulation state was measured as the duration of accumulation behavior following the extinction of the beam. The lifetime for the avoidance response state is approximately 3-4rain and that for the accumulation response is 19-28 rain. These data suggest that the two responses are based on distinct signals.
