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Rhizome gravitropism precedes gravimorphogenesis after inversion of the green algal coenocyte Caulerpa prolifera (Caulerpales)
Author(s) -
Jacobs William P.
Publication year - 1993
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1993.tb15364.x
Subject(s) - rhizoid , rhizome , gravitropism , amyloplast , botany , biology , phototropism , chloroplast , plastid , physics , blue light , biochemistry , arabidopsis , mutant , gene , optics
Previous investigations reported that the marine alga Caulerpa prolifera , a giant coenocyte, had a fast morphogenetic response to a change in position with regard to gravity: the next rhizoid formed approximately 1 day later on the new underside of the inverted rhizome (Jacobs and Olson, 1980, American Journal of Botany 67: 141–146). Preceding the change in site of rhizoid development was a striking accumulation of amyloplasts at the new prospective rhizoid‐initiation site in the rhizome tip. Detailed monitoring with video equipment of inverted Caulerpa plants, growing under controlled conditions, now reveals that after the amyloplast accumulation, but before the gravimorphogenetic effect on rhizoid development, the inverted rhizome tip shows a negative gravitropism that restores it to its normally upturned position. Because the experiments were performed with two‐sided illumination, this was clearly not a phototropic response.