Mercurial-sensitive water transport in barley roots

Masashi Tazawa, Eiji Ohkuma, Mineo Shibasaka, Susumu Nakashima

Research output: Contribution to journalArticlepeer-review

49 Citations (Scopus)

Abstract

An isolated barley root was partitioned into the apical and basal part across the partition wall of the double-chamber osmometer. Transroot water movement was induced by subjecting the apical part to a sorbitol solution, while the basal part with the cut end was in artificial pond water. The rate of transroot osmosis was first low but enhanced by two means, infiltration of roots by pressurization and repetition of osmosis. Both effects acted additively. The radial hydraulic conductivity (Lpr) was calculated by dividing the initial flow rate with the surface area of the apical part of the root, to which sorbitol was applied, and the osmotic gradient between the apical and basal part of the root. Lpr which was first 0.02-0.04 pm s-1 Pa-1 increased up to 0.25-0.4 pm s-1 Pa-1 after enhancement. Enhancement is assumed to be caused by an increase of the area of the plasma membrane which is available to osmotic water movement The inceased Lpr is in the same order of magnitude as the hydraulic conductivity (Lp) of epidermal and cortical cells of barley roots obtained by Steudle and Jeschke (1983). HgCl2, a potent inhibitor of water channels, suppressed Lpr of non-infiltrated and infiltrated roots down to 17% and 8% of control values, respectively. A high sensitivity of Lprto HgCl2 suggests that water channels constitute the most conductive pathway for osmotic radial water movement in barley roots.

Original languageEnglish
Pages (from-to)435-442
Number of pages8
JournalJournal of Plant Research
Volume110
Issue number4
Publication statusPublished - Dec 1997

Keywords

  • Barley root
  • HgCl
  • Hydraulic conductivity
  • Infiltration
  • Transroot osmosis
  • Water channels

ASJC Scopus subject areas

  • Plant Science

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