Ozone concentration in leaf intercellular air spaces is close to zero
1Institute of Astrophysics and Atmospheric Physics, 202444 Töravere, Tartu, Estonia, U.S.S.R.
Plant Physiology
|July 1, 1989
Summary
Ozone rapidly enters sunflower leaves through stomata and is quickly broken down. This study quantizes ozone uptake and leaf resistance, revealing zero intercellular ozone concentration.
Area of Science:
- Plant Physiology
- Environmental Science
- Biochemistry
Background:
- Ozone (O3) is a significant air pollutant impacting plant health.
- Understanding ozone uptake mechanisms is crucial for assessing plant damage and developing mitigation strategies.
Purpose of the Study:
- To simultaneously measure transpiration and ozone uptake in sunflower leaves.
- To determine the relationship between stomatal aperture, ozone concentration, and ozone uptake rates.
- To elucidate the pathway and fate of ozone within sunflower leaves.
Main Methods:
- Simultaneous measurement of transpiration and ozone uptake in sunflower leaves under varying stomatal openings and ozone concentrations.
- Calculation of leaf gas phase diffusion resistance for water vapor and ozone.
- Direct measurement of intercellular ozone concentration.
Main Results:
- Ozone uptake rates were proportional to ozone concentration up to 1500 nL/L.
- Calculated intercellular ozone concentration was found to be zero.
- Total leaf resistance to ozone was proportional to gas phase resistance to water vapor (coefficient 1.68).
Conclusions:
- Ozone enters sunflower leaves primarily through stomatal diffusion.
- Ozone is rapidly decomposed within the leaf, likely in cell walls and plasmalemma.
- The intercellular spaces of sunflower leaves maintain a zero ozone concentration due to rapid decomposition.
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