Long-term drought results in a reversible decline in photosynthetic capacity in mango leaves, not just a decrease in
Gaëlle Damour1, Marc Vandame, Laurent Urban
1CIRAD Persyst-UR 77, Station de Bassin Plat, BP 180, 97455 Saint Pierre Cedex, La Réunion, France.
Tree Physiology
|March 28, 2009
Summary
Long-term drought significantly reduces mango tree photosynthetic capacity, not just stomatal function. Photosynthesis recovers quickly after rewatering, indicating downregulation rather than photodamage.
Area of Science:
- Plant Physiology
- Drought Stress Physiology
Background:
- Drought negatively impacts plant growth and crop productivity.
- Long-term drought effects on photosynthetic capacity are not fully understood.
Purpose of the Study:
- To investigate the impact of prolonged drought on mango leaf photosynthetic capacity.
- To differentiate between stomatal limitation and intrinsic capacity decline.
Main Methods:
- Studied drought effects over 3.5 months in potted mango trees.
- Measured maximal net photosynthesis (Amax) and light-saturated electron transport (Jmax).
- Assessed leaf nitrogen and photosystem II quantum efficiency.
Main Results:
- Photosynthesis was limited by both stomatal closure and reduced photosynthetic capacity (Amax, Jmax).
- Drought-treated trees showed rapid recovery of Amax and Jmax after rewatering.
- Hexose-to-sucrose ratio increased, suggesting sink limitation.
Conclusions:
- Long-term drought downregulates mango photosynthetic capacity, not solely through stomatal closure.
- Photosynthetic machinery avoids photodamage, indicating reversible downregulation.
- Sink limitation may contribute to decreased photosynthetic capacity under drought.
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