title: Accumulation of amyloplasts on the bottom of normal and inverted rhizome tips of Caulerpa prolifera (Forsskål) Lamouroux.
abstract: Caulerpa prolifera (Chlorophyta) exhibits a gravimorphogenetic response to inversion by switching the site of new rhizoid initiations to correspond with the new direction of the gravity stimulus. When plants were fixed at 6 and 24 h after being held in either a normal or an inverted position the switch in the site of organ differentiation, upon inversion, was found to be preceded by the accumulation of starch-containing amyloplasts on the bottom of the rhizome. Approximately 1.5-2.0 times as many amyloplasts were found at the bottom of normal or inverted rhizomes as compared with the top in a region extending from 200 to 1,000 μm behind the rhizome tip. All new rhizoid initials were located in the region of amyloplast accumulation and each rhizoid initial contained numerous amyloplasts.
authors.affiliation: Department of Biology, Princeton University, 08544, Princeton, NJ, USA.
authors.forename: M B
authors.initials: MB
authors.lastname: Matilsky
authors.forename: W P
authors.initials: WP
authors.lastname: Jacobs