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Net O2 exchange rates under dark and light conditions across different stem compartments
Sara Natale1,2, Lucas Léon Peralta Ogorek3,4, Ludovico Caracciolo5
1Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, Trieste, 34127, Italy.
The New Phytologist
|May 4, 2024
Summary
Stem photosynthesis in woody plants like Fraxinus ornus is active in both bark and wood, with younger stems showing higher activity. Bark contributes most to oxygen production, but wood chloroplasts also photosynthesize and adapt to light.
Area of Science:
- Plant Physiology
- Woody Plant Biology
- Photosynthesis Research
Background:
- Woody plants exhibit stem photosynthetic activity, but its ecological significance and the roles of bark and wood remain unclear.
- Understanding stem photosynthesis is crucial for plant carbon budgets and survival strategies.
Purpose of the Study:
- To investigate the functional characteristics of chloroplasts in stems of varying ages in Fraxinus ornus.
- To quantify oxygen production rates and photosystem composition in stem tissues.
Main Methods:
- Utilized microsensor technology to measure oxygen production in whole stem, bark, and wood.
- Employed fluorescence lifetime imaging microscopy (FLIM) to determine the photosystem I to photosystem II chlorophyll ratio (PSI:PSII).
Main Results:
- Demonstrated light-induced oxygen production in all stem compartments (whole stem, bark, wood).
- Observed higher photosynthetic activity and respiration rates in younger stems compared to older ones.
- Identified bark as the main contributor to net oxygen production, with wood chloroplasts also being photosynthetically active and showing lower PSI abundance.
Conclusions:
- Stem chloroplasts in Fraxinus ornus are photosynthetically active and capable of light-dependent electron transport.
- Stem photosynthesis varies with stem age and tissue type, with adaptations in chloroplasts potentially related to light quality.
Keywords:
FLIMPSI : PSII Chl ratiomicrosensoroxygen exchange rateradial O2 profilestem photosynthesisMore Related Videos
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