ISSN:
1618-0860
Keywords:
Acid growth
;
Auxin
;
Cell wall apoplast
;
Elongation growth
;
Surface and xylem proton pumps
;
Symplast
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The roles of plasmalemma electrogenic proton pumps in elongation growth of plant stems are discussed on the basis of growth-electrophysiological studies on hypocotyl segments ofVigna unguiculata. Plant stems usually have two spatially separated electrogenic proton pumps: the surface proton pump which is located on the surface membrane of the symplast and the xylem proton pump, on the cell membrane of the symplast/xylem apoplast boundary. The surface proton pump excretes protons into the surface cell wall layer and causes the loosening of the cell wall. The xylem proton pump excretes protons into the xylem apoplast and drives the uptake of solute and water into the symplastvia secondary and/or tertiary active mechanisms: the proton cotransport system and the apoplast canal system. Both the surface and the xylem proton pumps are active during elongation growth because both the yielding of cell wall loosening and the uptake of water are necessary for continued elongation growth.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02344292
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