title: Kinetics of amyloplast sedimentation in gravistimulated maize coleoptiles.
abstract: Inner mesophyll cells from coleoptiles of Zea mays L. cv. Merit were fixed after varying periods of gravistimulation. A statistically significant amount (17-21%) of amyloplast sedimentation occurred in these cells after 30 s of gravistimulation. The presentation time is approx. 40 s or less. The accumulation of amyloplasts near the new lower wall shows a linear relationship to the logarithm of the gravistimulation time (r=0.92 or higher). The intercept of this line with the baseline value of amyloplasts in vertical coleoptiles indicates that the number of amyloplasts on the new lower wall begins increasing 11-15 s after the onset of gravistimulation. Direct observations of living cells confirm that many amyloplasts sediment within less than 15-30 s. These rapid kinetics are consistent with the classical statolith hypothesis of graviperception involving the sedimentation of amyloplasts to the vicinity of the new lower wall.
authors.affiliation: Boyce Thompson Institute for Plant Research, Cornell University, 14853, Ithaca, NY, USA.
authors.forename: F D
authors.initials: FD
authors.lastname: Sack
authors.forename: M M
authors.initials: MM
authors.lastname: Suyemoto
authors.forename: A C
authors.initials: AC
authors.lastname: Leopold