Title: Water Transport during Acid-Induced Growth of Excised Hypocotyl Sections of Vigna unguiculata under Xylem Perfusion
Abstract: Elongation growth of abraded hypocotyl sections of Vigna unguiculata under xylem perfusion was markedly promoted a few minutes after the application of an acid aerosol generated from a solution of HCl. At the beginning of the acid-induced growth, intracellular pressure (Pi) began to decrease and the membrane potential between the symplast and the xylem apoplast (Vpx) began to depolarize. Subsequently, Pi and Vpx remained at a reduced level and a depolarized level, respectively, while the promotion of elongation growth continued for more than 4 hours. The electrogenic component of the xylem membrane potential (Vpxact) gradually increased to about twice that before acid treatment. There was a close correlation between the enhanced growth and the decrease in intracellular pressure within 30 min after application of acid but little correltion after 60 min. By contrast, there was little correlation between the promotion of growth and the activity of the xylem pump after 30 min while a close correlation was observed after 60 min. It is inferred that the acid-induced activation of water uptake consists of two major processes, in series, that are driven by different forces: the rapid uptake of water for more than 30 min, driven by hydrostatic force generated by loosening of cell walls; and a long-lasting enhancement of water uptake for at least 4 h, which is driven by osmotic force that is generated by the canal system within the xylem.
Publication Year: 1995
Publication Date: 1995-04-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 2
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