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

Abstract

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.