Articles
GAS EXCHANGE IN ‘ALGERIE’ LOQUAT DURING ITS ANNUAL CYCLE IN THE MEDITERRANEAN BASIN
Article number
887_38
Pages
233 – 237
Language
English
Abstract
Loquat (Eriobotrya japonica Lindl.) is a subtropical evergreen fruit tree indigenous to southeastern China.
Loquat has recently expanded into the Mediterranean Basin, where experiences long periods of high temperatures and elevated evaporative demand during summer.
To study its adaptation to the Mediterranean climate, daily changes in leaf net photosynthetic rate, stomatal conductance, intercellular CO2 concentration, in relation to leaf and stem water potential, and to volumetric soil water content were traced along the annual cycle of Algerie loquats cultivated in the Southeast Coast of Spain.
Gas exchange parameters were determined with a portable photosynthesis system CIRAS-2 in trees under standard orchard management every two hours, from dawn to sunset, in the middle of summer, autumn, winter and spring.
In addition, monthly measurements were taken at noon.
Aiming to establish a relation between gas exchange parameter and plant and soil water status, leaf and stem water potential were estimated with a pressure chamber and soil volumetric water content by Time Domain Reflectometry (TDR). Diurnal and seasonal leaf photosynthesis (A) and stomatal conductance (Gs) values responded to variations in tree water status and to changes in evaporative demand The curves of diurnal A were generally single-picked.
The maximum A value usually occurred around 11:00 h solar time in spring, summer and autumn, while used to happen at 10:00 h solar time in winter.
A and Gs values were commonly higher in spring, autumn and winter than in summer.
The lowest A values were measured in summer, probably because the high temperature and the low humidity negatively affected soil water content and plant water status.
Gs diurnal changes exhibited a similar seasonal trends than that reported for A. Stomata closure during summer to reduce water loss decreased CO2 assimilation as well.
Loquat has recently expanded into the Mediterranean Basin, where experiences long periods of high temperatures and elevated evaporative demand during summer.
To study its adaptation to the Mediterranean climate, daily changes in leaf net photosynthetic rate, stomatal conductance, intercellular CO2 concentration, in relation to leaf and stem water potential, and to volumetric soil water content were traced along the annual cycle of Algerie loquats cultivated in the Southeast Coast of Spain.
Gas exchange parameters were determined with a portable photosynthesis system CIRAS-2 in trees under standard orchard management every two hours, from dawn to sunset, in the middle of summer, autumn, winter and spring.
In addition, monthly measurements were taken at noon.
Aiming to establish a relation between gas exchange parameter and plant and soil water status, leaf and stem water potential were estimated with a pressure chamber and soil volumetric water content by Time Domain Reflectometry (TDR). Diurnal and seasonal leaf photosynthesis (A) and stomatal conductance (Gs) values responded to variations in tree water status and to changes in evaporative demand The curves of diurnal A were generally single-picked.
The maximum A value usually occurred around 11:00 h solar time in spring, summer and autumn, while used to happen at 10:00 h solar time in winter.
A and Gs values were commonly higher in spring, autumn and winter than in summer.
The lowest A values were measured in summer, probably because the high temperature and the low humidity negatively affected soil water content and plant water status.
Gs diurnal changes exhibited a similar seasonal trends than that reported for A. Stomata closure during summer to reduce water loss decreased CO2 assimilation as well.
Publication
Authors
A. Stellfeldt, J. Cuevas, J.J. Hueso
Keywords
leaf photosynthetic rate, stomatal conductance, water potential, Mediterranean climate
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