Changes in grapevine leaf phenolic profiles during the day are temperature rather than irradiance driven
Kristóf Csepregi1, Péter Teszlák2, László Kőrösi2
1Department of Plant Biology, University of Pécs, Pécs, Hungary.
Plant Physiology and Biochemistry : PPB
|February 24, 2019
Summary
Grapevine leaves adapt to sunlight by altering flavonoid and phenolic compounds. These changes, particularly quercetin-3-O-glucoside, help protect photosynthesis from UV radiation and temperature stress.
Area of Science:
- Plant Physiology
- Biochemistry
- Environmental Science
Background:
- Grapevine (Vitis vinifera) leaves are exposed to fluctuating environmental conditions.
- Understanding leaf responses to solar irradiance and temperature is crucial for optimizing grape production.
Purpose of the Study:
- To investigate the hourly changes in photosynthesis, flavonoid index, phenolic profiles, and antioxidant capacities of grapevine leaves.
- To correlate these leaf parameters with environmental factors like solar irradiance and temperature.
Main Methods:
- Hourly measurements of photosynthesis, adaxial flavonoid index, phenolic profiles, and antioxidant capacities.
- Statistical analysis correlating leaf parameters with environmental data (solar irradiance, UV, temperature, humidity).
- High-Performance Liquid Chromatography (HPLC) for detailed phenolic profiling.
Main Results:
- Flavonoid index correlated positively with irradiance and leaf temperature.
- Total phenolic content correlated positively with air temperature.
- Quercetin-3-O-glucoside showed positive correlations with flavonoid index, photosynthesis, and CO2 concentration, suggesting a protective role.
- Solar UV-A and UV-B had a short-term negative impact on CO2 uptake, independent of stomatal conductance.
Conclusions:
- Quercetin-3-O-glucoside plays a significant role in protecting grapevine leaves against environmental stress.
- Leaf antioxidant capacity is influenced by solar UV and temperature.
- UV radiation can temporarily impair photosynthesis in grapevines.
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