Methanol emissions from deciduous tree species: dependence on temperature and light intensity

Area of Science:

• Plant physiology
• Biogeochemistry
• Atmospheric chemistry

Background:

• Methanol is a volatile organic compound emitted by plants.
• Understanding methanol emission regulation is crucial for atmospheric chemistry and plant science.

Purpose of the Study:

• To investigate the influence of light and temperature on methanol emissions from deciduous trees.
• To elucidate the origin and transport mechanisms of emitted methanol.

Main Methods:

• Laboratory and field measurements of methanol emissions.
• Controlled experiments varying light intensity and temperature.
• Isotopic labeling with (13)CO(2) to trace methanol production.
• Root cooling experiments to assess transport pathways.

Main Results:

• Methanol emissions increased with leaf temperature (up to 12%/°C) and light intensity (doubling with PAR increase).
• A phenomenological model accurately described light and temperature dependencies.
• Less than 10% of methanol was photosynthetically produced de novo.
• Root and stem production, transported via transpiration, contributed substantially but were not the sole determinant.

Conclusions:

• Methanol emission regulation in trees is complex, influenced by both environmental factors and internal plant processes.
• The primary source of emitted methanol is likely not direct photosynthesis, with significant contributions from other plant tissues.
• Transpiration plays a role in methanol transport but does not fully explain emission patterns.