What information is conveyed by an ABA signal from maize roots in drying field soil?

F. TARDIEU*, Jianhua ZHANG, W. J. DAVIES

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

99 Citations (Scopus)

Abstract

During two seasons, ABA concentrations were monitored in roots, leaves and xylem sap of field‐grown maize. The water status of soil and plant was also measured. Plants were grown on plots with compacted or non‐compacted soil, which were irrigated or remained unwatered. ABA concentration in the xylem sap before dawn and in the roots increases 25‐fold and five‐fold, respectively, as the soil dried, with a close correlation with the soil water status, but with no clear effect of the soil structure. In contrast to the results of several laboratory experiments, no appreciable increase in xylem [ABA] and reduction in stomatal conductance were observed with dehydration of the part of the root system located in soil upper layers. These responses only occurred when the water reserve of the whole soil profile was close to depletion and the transpiration declined. Xylem [ABA] measured during the day was appreciably higher in the compacted treatment than in non‐compacted treatment, unlike that measured before dawn. Since a mechanical message is unlikely to undergo such day‐night alterations, we suggest that this was due to a faster decrease in root water potential and water flux in the compacted treatment, linked to the root spatial arrangement. These results raise the possibility that ABA concentration in the xylem sap could be controlled by two coexisting mechanisms: (1) the rate of ABA synthesis in the roots linked to the soil or root water status, as shown in laboratory experiments; (2) the dilution of ABA in the water flow from roots, which could be an overriding mechanism in field conditions. This second mechanism would allow the plant to sense the water flux through the root system.

Original languageEnglish
Pages (from-to)185-191
Number of pages7
JournalPlant, Cell and Environment
Volume15
Issue number2
DOIs
Publication statusPublished - Feb 1992

Scopus Subject Areas

  • Physiology
  • Plant Science

User-Defined Keywords

  • ABA
  • leaf water potential
  • maize
  • soil compaction
  • soil water status
  • stomatal conductance

Fingerprint

Dive into the research topics of 'What information is conveyed by an ABA signal from maize roots in drying field soil?'. Together they form a unique fingerprint.

Cite this