Davies W. J. Wilson J. A., Sharp R. E., Osonubi O., (1980)
In: Stomatal Physiology (eds.) P.G. Jarvis, and T.A. Mansfield). C.U.P., London (1980), 165-184 –
(Continued)
by Osonubi O., Davies W. J. (1980)
In Oecologia (Berl.) 45: 3-10 – https://doi.org/10.1007/BF00346699 –
https://link.springer.com/article/10.1007/BF00346699
Abstract
Seedlings of Betula pendula Roth. and Gmelina arborea L. were subjected to variation in temperature and irradiance. The influence of a mild water-stressing treatment on the photosynthetic performance and stomatal behaviour of these plants was assessed. For both species, the shape of the relationships between irradiance and photosynthesis and temperature and photosynthesis resembled those reported for other species.
The effect of water stress was to reduce the rate of photosynthesis, particularly at high temperatures. This was largely a function of a reduction in mesophyll conductance under these conditions. The optimum temperature for stomatal opening was significantly lower than the optimum temperature for photosynthesis, which was in turn lowered by the water stress treatment.
The stomata of birch seedlings showed maximum opening at an intermediate temperature while the stomata of Gmelina generally exhibited a closing movement when leaf temperatures increased from 15° C. Mesophyll conductances of both species increased with increasing temperature.
The physiological basis for the variation in photosynthetic performance and stomatal behaviour and the ecological significance of this variation are discussed.
by Osonubi O., Davies W. J. (1980)
in Oecologia (Berl.) 45, 3–10 – doi:10.1007/BF00346699 –
http://link.springer.com/article/10.1007/BF00346699
Summary
Seedlings of Betula pendula Roth. and Gmelina arborea L. were subjected to variation in temperature and irradiance. The influence of a mild water-stressing treatment on the photosynthetic performance and stomatal behaviour of these plants was assessed.
For both species, the shape of the relationships between irradiance and photosynthesis and temperature and photosynthesis resembled those reported for other species. The effect of water stress was to reduce the rate of photosynthesis, particularly at high temperatures. This was largely a function of a reduction in mesophyll conductance under these conditions.
The optimum temperature for stomatal opening was significantly lower than the optimum temperature for photosynthesis, which was in turn lowered by the water stress treatment.
The stomata of birch seedlings showed maximum opening at an intermediate temperature while the stomata of Gmelina generally exhibited a closing movement when leaf temperatures increased from 15° C. Mesophyll conductances of both species increased with increasing temperature.
The physiological basis for the variation in photosynthetic performance and stomatal behaviour and the ecological significance of this variation are discussed.
by Osonubi O., Davies W. J. (1980)
in Oecologia (Berlin) 46: 1–6. – DOI: 10.1007/BF00346957 –
http://link.springer.com/article/10.1007/BF00346957
Summary
Leaves of well-watered and mildly water-stressed seedlings of Betula pendula Roth. and Gmelina arborea L. were subjected to a range of vapour pressure deficits (VPD) between 10 and 24 kPa.
The stomatal conductance of birch seedlings decreased as VPD was increased and at least in mildly-stressed seedlings this response seemed to be closely linked to the water status of the air rather than to the bulk water status of the plant.
Mild water stressing enhanced the degree of the stomatal humidity-response and resulted in a significant increase in the efficiency of water use at high VPD.
Stomata of Gmelina were apparently insensitive to variation in VPD, but were more sensitive to a decrease in bulk leaf water status than were stomata of birch.
Water use efficiency of Gmelina seedlings was comparatively high, even when VPD was high and the stomata were fully open.
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