Water potential, turgor and cell wall properties in elongating tissues of the hydrotropically bending roots of pea (Pisum sativum L.)

T. Hirasawa, H. Takahashi, H. Suge, K. Ishihara

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)

Abstract

The hydrotropic bending of roots of an ageotropic pea mutant, ageotropum, was studied in humid air in a chamber with a steady humidity gradient. We examined the effects of atmospheric humidity around the root on the water status of root tissues, as well as the wall growth and the hydraulic properties of the elongating tissues. Atmospheric humidity at the surface of the root was clearly lower on the side orientated towards the air with lower humidity than on the side orientated towards the air with higher humidity. However, there were no differences in water potential and osmotic potential between the tissues that faced air with higher and lower humidities in the elongating and mature regions. Plastic extensibility was higher in the tissues that faced the air with lower humidity than in the tissues that faced the air with higher humidity. No differences in turgor pressure and yield threshold were observed between the tissues that faced air with higher and lower humidities. Therefore, the extensibility of the cell wall appeared to he responsible for the different growth rates of tissues in root hydrotropism. A further probable cause of the hydrotropical bending of roots is changes in the hydraulic conductance in the elongating tissues. Since the hydrotropic bending of roots occurred only when a rout tip was exposed to a humidity gradient, hydrotropism might occur after perception of a difference in humidity by the root tip, with accompanying changes in cell wall extensibility and hydraulic conductance.

Original languageEnglish
Pages (from-to)381-386
Number of pages6
JournalPlant, Cell and Environment
Volume20
Issue number3
DOIs
Publication statusPublished - 1997 Mar

Keywords

  • Leguminosae
  • Pisum sativum L.
  • air humidity
  • cell-wall extensibility
  • hydraulic conductance
  • pea
  • root hydrotropism
  • turgor pressure
  • water potential
  • yield threshold

ASJC Scopus subject areas

  • Physiology
  • Plant Science

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