Article ID Journal Published Year Pages File Type
9620468 Forest Ecology and Management 2005 14 Pages PDF
Abstract
Leaf conductance decreased if Ψx fell below certain values after the noon, while the sun foliage experienced greater negative water potentials than the shade foliage. In a diurnal scale the influence of bulk leaf water potential on gL altogether was rather weak. The lower-canopy foliage exhibited more conservative water-use behaviour, having lower maximum stomatal conductance and greater sensitivity to Ψx bringing about a smaller responsiveness to VPD than the upper canopy foliage. The mean GT was 1.7-1.8 times bigger (P < 0.001) for the upper canopy, compared to the lower canopy; the shade foliage responded more sensitively to changes in GT; there were steeper water potential gradients between the soil and lower-canopy leaves; gL in the lower-canopy foliage was more strictly controlled by leaf water status-the evidence suggesting that the shade foliage may be hydraulically more constrained. We set up a hypothesis that stomatal conductance at the base of the live crown is limited not only by low light availability but also by plant's inner hydraulic constraints.
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Life Sciences Agricultural and Biological Sciences Ecology, Evolution, Behavior and Systematics
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