Planta

, Volume 210, Issue 3, pp 454–467

Simulating ozone detoxification in the leaf apoplast through the direct reaction with ascorbate

  • Matthias Plöchl
  • Tom Lyons
  • John Ollerenshaw
  • Jeremy Barnes
Article

Abstract.

 This paper presents a mathematical model which enables the semi-quantification of ozone (O3) detoxification, based upon the direct reaction of the pollutant with ascorbate (ASC) located in the aqueous matrix associated with the cell wall (i.e. the apoplast). The model describes the uptake of ozone into the leaf and its direct reaction with ASC, taking into consideration the regeneration of dehydroascorbic acid in the cytosol, the rate of replenishment of cell wall ASC and the distribution of ASC between sub-cellular compartments – based upon the permeability of biomembranes to the neutral species, ascorbic acid and the pH of various sub-cellular compartments. The importance of various physico-chemical characteristics (e.g. stomatal conductance, mesophyll cell wall thickness and tortuosity, chloroplast volume, apoplast pH, ASC:O3 reaction stoichiometry) in mediating the flux of ozone to the plasmalemma is analysed. Model simulations, supported by experimental observations, suggest that the ASC concentration in the leaf apoplast is high enough to scavenge a significant proportion of the O3 taken up into the leaf interior, under environmentally relevant conditions. However, there is considerable variation between taxa in the potential degree of protection afforded by apoplastic ASC, emphasizing the need for an improved understanding of the reaction chemistry of O3 in the cell wall.

Key words: Ascorbic acid – Compartmentation (ascorbate) – Computer model – Detoxification (ozone) – Leaf apoplast – Ozone 

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Copyright information

© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • Matthias Plöchl
    • 1
  • Tom Lyons
    • 2
  • John Ollerenshaw
    • 2
  • Jeremy Barnes
    • 2
  1. 1.Institute of Agricultural Engineering Bornim (ATB), Max-Eyth-Allee 100, 14469 Potsdam-Bornim, GermanyDE
  2. 2.Air Pollution Laboratory, Department of Agricultural and Environmental Science, Ridley Building, The University, Newcastle Upon Tyne, NE1 7RU, UKGB

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