CSIRO Publishing blank image blank image blank image blank imageBooksblank image blank image blank image blank imageJournalsblank image blank image blank image blank imageAbout Usblank image blank image blank image blank imageShopping Cartblank image blank image blank image You are here: Journals > Functional Plant Biology   
Functional Plant Biology
Journal Banner
  Plant Function & Evolutionary Biology
blank image Search
blank image blank image
blank image
  Advanced Search

Journal Home
About the Journal
Editorial Structure
Online Early
Current Issue
Just Accepted
All Issues
Special Issues
Research Fronts
Evolutionary Reviews
Sample Issue
Call for Papers
For Authors
General Information
Submit Article
Author Instructions
Open Access
Awards and Prizes
For Referees
Referee Guidelines
Review an Article
Annual Referee Index
For Subscribers
Subscription Prices
Customer Service
Print Publication Dates

blue arrow e-Alerts
blank image
Subscribe to our Email Alert or RSS feeds for the latest journal papers.

red arrow Connect with us
blank image
facebook twitter logo LinkedIn

red arrow PrometheusWiki
blank image
Protocols in ecological and environmental plant physiology


Article << Previous     |     Next >>   Contents Vol 30(10)

Review: Mechanisms of anoxia tolerance in plants. II. Energy requirements for maintenance and energy distribution to essential processes

Hank Greenway and Jane Gibbs

Functional Plant Biology 30(10) 999 - 1036
Published: 20 October 2003


Anoxia in plant tissues results in an energy crisis (Gibbs and Greenway 2003). How anoxia-tolerant tissues cope with such an energy crisis is relevant not only to anoxia tolerance, but also to adverse conditions in air that cause an energy crisis.

To survive an energy crisis, plant cells need to reduce their energy requirements for maintenance, and also direct the limited amount of energy produced during anaerobic catabolism to the energy-consuming processes that are critical to survival.

We postulate that during anoxia, reductions in ion fluxes and protein turnover achieve economies in energy consumption. Processes receiving energy from the limited supply available under anoxia include synthesis of anaerobic proteins and energy-dependent substrate transport. Energy would also be required for maintenance of membrane integrity and for regulation of cytoplasmic pH (pHcyt). We suggest that a moderate decrease in the set point of pHcyt, from approximately 7.5 to approximately 7.0 is an acclimation to the energy crisis in anoxia-tolerant tissues. This decrease in the set point of pHcyt would favour metabolism of acclimative value, such as reduction in protein synthesis and stimulation of ethanolic fermentation. During anoxia lasting several days, a proportion of the scarce energy produced may need to be spent to mitigate the acidifying effect on pHcyt arising from fluxes of undissociated organic acids across the tonoplast as a consequence of high concentrations of organic acids in the vacuole. Increases in vacuolar pH (pHvac), with concomitant decreases in the vacuolar concentrations of undissociated acids, would mitigate such an 'acid load' on the cytoplasm. We present evidence that a preferential engagement of V-PPiases, over that of V-ATPases, may direct energy flow at the tonoplast to maintain pHcyt.

We conclude that the likely causes of death under anoxia are firstly, a decrease in pHcyt below 7.0. Cytoplasmic acidosis occurs in several anoxia-intolerant tissues and may contribute to their death. Such adverse decreases in pHcyt can be mitigated by the biochemical pH stat. Secondly, deterioration in membrane selectivity culminating in loss of membrane integrity would be fatal. We suggest these two causes are not mutually exclusive but may act in concert.

Keywords: anoxia, energy requirements for maintenance, membrane integrity, protein synthesis, regulation of pHcyt, solute transport.

Full text doi:10.1071/PP98096

© CSIRO 2003

blank image
Subscriber Login

PDF (394 KB) $25
 Export Citation
Legal & Privacy | Contact Us | Help


© CSIRO 1996-2015