Plant and Cell Physiology, 1990, Vol. 31, No. 4 457-462
© 1990
Article |
Gravity-Induced Changes in Intracellular Potentials in Elongating Cortical Cells of Mung Bean Roots
Department of Botany, The Ohio State University Columbus, OH 43210, U.S.A.
Gravity-induced changes in intracellular potentials in primary roots of 2-day-old mung bean (Vigna mungo L. cv. black matpe) seedlings were investigated using glass microelectrodes held by 3-dimensional hydraulic micro-drives. The electrodes were inserted into outer cortical cells within the elongation zone. Intracellular potentials, angle of root orientation with respect to gravity, and position within the root of the impaled cortical cell were measured simultaneously. Gravi-stimulation caused intracellular potential changes in cortical cells of the elongation zone. When the roots were oriented vertically, the intracellular potentials of the outer cortical cells (2 mm behind the root apex) were approximately –115 mV. When the roots were placed horizontally cortical cells on the upper side hyperpolarized to –154 mV within 30 s while cortical cells on the lower side depolarized to about –62 mV. This electrical asymmetry did not occur in cells of the maturation zone. Because attempts to insert the electrode into cells of the root cap were unsuccessful, these cells were not measured. The hyperpolarization of cortical cells on the upper side was greatly reduced upon application of N,N'-dicyclohexylcarbodiimide (DCCD), an inhibitor of respiratory energy coupling. When stimulated roots were returned to the vertical, the degree of hyperpolarization of cortical cells on the previous upper side decreased within 30 s and approached that of cortical cells in non-stimulated roots. This cycle of hyperpolarization/loss of hyperpolarization was repeatable at least ten times by alternately turning the root from the vertical to the horizontal and back again.
The very short (<30 s) lag period of these electrical changes indicates that they may result from stimulus-perception and transduction within the elongation zone rather than from transmission of a signal from the root cap.
(Received August 28, 1989; Accepted March 7, 1990)
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  C. Guan, E. S. Rosen, K. Boonsirichai, K. L. Poff, and P. H. Masson The ARG1-LIKE2 Gene of Arabidopsis Functions in a Gravity Signal Transduction Pathway That Is Genetically Distinct from the PGM Pathway Plant Physiology, September 1, 2003; 133(1): 100 - 112. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. S. Ober and R. E. Sharp Electrophysiological responses of maize roots to low water potentials: relationship to growth and ABA accumulation J. Exp. Bot., February 1, 2003; 54(383): 813 - 824. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. D. Firn, C. Wagstaff, and J. Digby The use of mutants to probe models of gravitropism J. Exp. Bot., August 1, 2000; 51(349): 1323 - 1340. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. L. Mullen, C. Wolverton, H. Ishikawa, and M. L. Evans Kinetics of Constant Gravitropic Stimulus Responses in Arabidopsis Roots Using a Feedback System Plant Physiology, June 1, 2000; 123(2): 665 - 670. [Abstract] [Full Text]
|
|
|
|
|
|
W. S. Peters and H. H. Felle The Correlation of Profiles of Surface pH and Elongation Growth in Maize Roots Plant Physiology, November 1, 1999; 121(3): 905 - 912. [Abstract] [Full Text]
|
|
|
|
|
|
E. B. Blancaflor, J. M. Fasano, and S. Gilroy Mapping the Functional Roles of Cap Cells in the Response of Arabidopsis Primary Roots to Gravity Plant Physiology, January 1, 1998; 116(1): 213 - 222. [Abstract] [Full Text]
|
|