POLARIZED-LIGHT INDUCES NUCLEAR MIGRATION IN PROTHALLIAL CELLS OF ADIANTUM-CAPILLUS-VENERIS L

In irradiated prothallial cells of Adiantum capillus-veneris L. the nuclei are located at the periclinal wall, whereas they are located at the anticlinal wall in darkness (Kagawa and Wada, 1993, Protoplasma 177, 82-85). The migration of the nuclei could be induced in cells preadapted in the dark, by irradiation with both polarized red (R) and blue light (B). When the dark-adapted prothallial cells were irradiated from the horizontal direction with horizontally vibrating polarized light, the nuclei moved from the anticlinal walls to the periclinal walls. It took 3 h for 50% of the nuclei to leave the anticlinal walls. Vertically vibrating polarized light did not have such an effect, and the nuclei stayed at the anticlinal walls. Simultaneous irradiation of polarized R or B with non-polarized far-red light reduced the effect of R but not of B, indicating the involvment of phytochrome and a blue light-absorbing pigment in the R and B effects, respectively. When light-adapted prothallial cells were irradiated from the horizontal direction with vertically vibrating polarized light, the nuclei migrated from the periclinal walls to the anticlinal walls. About half of the nuclei left the periclinal walls within 6 h after the onset of the vertically polarized light. When the prothalli were irradiated with horizontally vibrating polarized light, it took more than 18 h. These results suggest that the light-induced nuclear migration is caused by a gradient of light-activated photoreceptors, i.e. phytochrome and blue-light-absorbing pigment.