Article

Planta

, Volume 161, Issue 5, pp 459-464

Kinetics of amyloplast sedimentation in gravistimulated maize coleoptiles

  • F. D. SackAffiliated withBoyce Thompson Institute for Plant Research, Cornell University
  • , M. M. SuyemotoAffiliated withBoyce Thompson Institute for Plant Research, Cornell University
  • , A. C. LeopoldAffiliated withBoyce Thompson Institute for Plant Research, Cornell University

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

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.

Key words

Amyloplast sedimentation Coleoptile (gravistimulation) Graviperception Zea (graviperception)