|
|
||||||||
|
Plant Physiology Preview Published on September 28, 2007; 10.1104/pp.107.107318
OPEN ACCESS ARTICLE
Received August 15, 2007 Lateral CO2 Diffusion Inside Dicotyledonous Leaves can be Substantial: Quantification in Different Light Intensities
Department of Biological Sciences, University of Essex, Colchester, UK; Laboratoire d'Ecologie Systématique et Evolution, Département d'écophysiologie végétale, Bât.362, Faculté des sciences d'Orsay, Université Paris XI, 91405 Orsay, France * Corresponding author; email: morisj{at}essex.ac.uk.
Substantial lateral CO2 diffusion rates into leaf areas where stomata were blocked by grease patches were quantified by gas exchange and chlorophyll a fluorescence imaging in different species across the full range of photosynthetic photon flux densities (PPFD). The lateral CO2 flux rate over short distances was substantial and very similar in 5 dicotyledonous species with different vascular anatomies (two species with bundle sheath extensions: sunflower and dwarf bean, and three species without bundle sheath extensions: faba bean, petunia and tobacco). Only in the monocot maize was there little or no evident lateral CO2 flux. Lateral diffusion rates were low when PPFD <300 µmol m-2 s-1, but approached saturation in moderate PPFD (300 µmol m-2 s-1) when lateral CO2 diffusion represented 15-24% of the normal CO2 assimilation rate. Smaller patches and higher ambient CO2 concentration increased lateral CO2 diffusion rates. Calculations with a 2-D diffusion model supported these observations that lateral CO2 diffusion over short distances inside dicotyledonous leaves can be important to photosynthesis. The results emphasize that supply of CO2 from nearby stomata usually dominates assimilation, but that lateral supply over distances up to approx. 1.0 mm can be important if stomata are blocked, particularly when assimilation rate is low.
This article has been cited by other articles:
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| ASPB Publications | PLANT PHYSIOLOGY | THE PLANT CELL | |
|---|---|---|---|