02099naa a2200253 a 450000100080000000500110000800800410001910000120006024501550007226000090022752013530023665000130158965000190160265000160162165000220163765300100165965300110166965300200168065300080170065300390170865300200174770000160176777300620178310524771997-04-16       1988    bl ---       0--  u    #d1 aLIU, Q.  aEffects of osmotic stress, salt stress and IAA on the regeneration of the resting membrane potential after excision of a segment from an intact plant.  c1988  aEffects of osmotic stress, salt stress and IAA on the regeneration process of the transmembrane potential across the xylem/symplast interface (Vpx) of newly excised hypocotyl segments of Vigna seedlings were examined by means of the xylem perfusion method. It took about 8 h under ordinary conditions for an excised segment to regenerate a membrane potential comparable with that of an intact seedling. Osmotic stress imposed by perfusion of 100-100 mM sorbitol solution seemed to accelerate this process. This effect diminished with the removal of sorbitol from the perfusion solution. The increase in the negativity of Vpx in this regeneration process resulted from the increases in both passive (Vpx in N2) and respiration-dependent components (Vpx). NaCl (50-100 mM) did not accelerate the regeneration of the total membrane potential, but significantly promoted an increase in Vpx, i.e. electrogenic xylem pump activity. Perfusion of KCl (50-100 mM) or IAA (10-4M) shortened the regeneration phase up to 2-3 h. The increase in total Vpx under salt stress or IAA mainly resulted from the increase of Vpx. The effect of those agents on the Vpx is discussed, as is the question of whether the increase in PD after excision should be interpreted as recovery or regeneration from injury by excision, or as a so-called release from hormonal control.  aexcision  aosmotic stress  asalt stress  aVigna Unguiculata  aCaupi  aCowpea  aEstresse salino  aIAA  aRegeneration of membrane potential  aXylem perfusion1 aOKAMOTO, H.  tPlant and Cell Physiologygv. 29, n. 4, p. 597-603, 1988.