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Carbon Source Reduction Postpones Autumn Leaf Senescence in a Widespread Deciduous Tree
Julia Maschler1, Jenna Keller1, Lalasia Bialic-Murphy1
1Department of Environmental Systems Science, ETH Zürich, Zurich, Switzerland.
Frontiers in Plant Science
|June 20, 2022
Summary
Carbon sink limitation influences autumn leaf senescence in birch trees. Manipulating carbon dynamics delayed leaf senescence, supporting its role in regulating growing-season length and climate change impacts.
Area of Science:
- Plant Biology
- Ecology
- Climate Change Science
Background:
- Growing-season length in temperate and boreal trees significantly impacts the global carbon cycle.
- Understanding drivers of autumn leaf senescence is crucial for predicting growing-season length under climate change.
- While temperature is a known factor, carbon source-sink dynamics offer a potential explanation for variations in senescence timing.
Purpose of the Study:
- To investigate the role of carbon sink limitation in autumn leaf senescence and photosynthetic decline in birch (Betula pendula).
- To test the carbon sink limitation hypothesis by manipulating carbon source-sink dynamics in experimental settings.
Main Methods:
- Conducted gradient leaf and bud removal experiments on birch saplings.
- Monitored changes in net photosynthesis and the timing of leaf senescence.
- Assessed the impact of treatments on plant carbon sink strength.
Main Results:
- Leaf removal treatments led to increased leaf-level autumn photosynthesis and delayed leaf senescence.
- Bud removal did not significantly affect photosynthesis or senescence, likely due to minimal impact on plant carbon sink.
- Results align with the carbon sink limitation hypothesis.
Conclusions:
- Carbon sink limitation is a significant driver of autumn leaf senescence and growing-season length in deciduous trees.
- Findings contribute to reducing uncertainty in climate change predictions related to plant phenology.
- Further research should consider potential confounding factors like leaf age and soil resources.
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