Microfilaments anchor chloroplasts along the outer periclinal wall in Vallisneria [Hydrocharitaceae] epidermal cells through cooperation of PFR and photosynthesis
1998
Dong, X.J. (Osaka Univ., Suita (Japan)) | Nagai, R. | Takagi, S.
In the cytoplasmic layer than faces the outer periclinal wall in epidermal cells of leaves of the aquatic angiosperm Vallisneria gigantea Graebner, we examined a possible interrelationship among the configuration of Microfilaments, chloroplast motility, and anchoring of chloroplasts. In dark-adapted cells, microfilaments are arranged in a network array. During a 10-min incubation in darkness 10 to 20 min after irradiation with red light (650 nm, 0.41 W m(-2)) for 5 min, the number of cells containing a network array decreased substantially while the number of cells containing microfilaments in a honeycomb array increased. Irradiation with red light rapidly produces an increase in chloroplast motility, but chloroplast motility declined almost to initial levels during the 10-min incubation in darkness after the irradiation. Simultaneously, the chloroplasts in these cells became extremely resistant to centrifugal forces. These effects of red light were negated either by far-red light or by the presence of DCMU, and were sensitive to cytochalasin B. It appears, therefore, that microfilaments not only drive the movement of chloroplasts but also play a crucial role in accumulation of the chloroplasts along the outer periclinal wall through dynamic changes in the configuration under cooperative regulation by PFR and photosynthesis
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