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Photosynthesis in Coffea arabica. II. Effects of Water Stress

Published online by Cambridge University Press:  03 October 2008

D. Kumar
Affiliation:
Coffee Research Station, Ruiru, Kenya
Larry L. Tieszen
Affiliation:
Department of Botany, University of Nairobi, Kenya

Summary

Experiments were carried out to relate soil moisture to leaf water potential (Ψ1), and to determine the effects of varying Ψ1, on leaf conductances and photosynthesis in coffee. Stomatal conductance was maximum at 0900 h, but plants growing in drier soil showed marked mid-day stomatal closure. After 1500 h, stomata began closing although plant water status improved. Photosynthesis in relation to changing Ψ1 appeared to exhibit roughly three different rates. At the fixed experimental temperature (25°C) low Ψ1 reduced photosynthesis throughits influence on stomata, but under field conditions low Ψ1 and an accompanying rise in temperature could lower the rate by lowering both mesophyll and stomatal conductances.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1980

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References

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