Protonemata Of Adiantum Capillus-veneris Research Articles

Effects of hypergravity on the elongation and morphology of protonemata of Adiantum capillus‐veneris

Elongation growth of protonemata of Adiantum capillus‐veneris, which can be controlled by light irradiation, was examined under acropetal and basipetal hypergravity conditions (from ‐13 to +20 g) using a newly developed centrifugation equipment. Elongation of the protonemata under red light was inhibited by basipetal hypergravity at more than +15 g but was promoted by acropetal hypergravity from ‐5 to ‐8 g. Division of the protonemal cells that was induced by white light was inhibited under basipetal hypergravity at +20 g but was unaffected under acropetal hypergravity at ‐15 g. Upon exposure to continuous red light for 7 to 8 days, most of the protonemata grew as filamentous cells in the absence of a change in the normal gravitational force (control), but more than half of the protonemal cells were abnormal in terms of shape when maintained under hypergravity at +20 g.

Effects of hypergravity on the elongation and morphology of protonemata of Adiantum capillus-veneris

Effects of hypergravity on the elongation and morphology of protonemata of Adiantum capillus-veneris

Effects of simulated microgravity on the germination and elongation of protonemata of Adiantum capillus-veneris

Effects of simulated microgravity on the germination and elongation of protonemata of Adiantum capillus-veneris

The changes of nuclear position and distribution of circumferentially aligned cortical microtubules during the progression of cell cycle inAdiantum protonemata

The intracellular positions of the nucleus and of cortical, circumferentially aligned microtubules (CCAM) in filamentous, single-celled protonemata ofAdiantum capillus-veneris were determined throughout the cell cycle in the dark. When apical growth continued at G1 phase, the nucleus migrated keeping a constant distance from the tip. When the apical growth stopped at late S or G2 phase, the nucleus stopped moving forward and then slightly moved backward to the site of cytokinesis. The CCAM were found only in the dome of protonemal tip when growing under continuous red light; they increased in number after dark incubation for 12 hr and then decreased after 20th hr in the dark. The CCAM were usually observed in the region between the nucleus and the tip at 28 hr in the dark. They were located around the nuclear region at pre-prophase and prophase, but then totally disappeared at metaphase and thereafter.