Title: The citrus leaf cuticle in relation to measurement of leaf water potential using thermocouple psychrometers<sup>*</sup>
Abstract:Abstract. Cuticular resistance to water vapour diffusion is an important aspect of thermocouple psychrometry and may introduce significant error in the measurement of leaf water potential (Ψ). The eff...Abstract. Cuticular resistance to water vapour diffusion is an important aspect of thermocouple psychrometry and may introduce significant error in the measurement of leaf water potential (Ψ). The effect of the citrus ( Citrus mitis Blanco) leaf cuticle on water vapour movement was studied using the times required for vapour pressure equilibration during thermocouple psychrometric measurement of Ψ. Cuticular abrasion with various carborundum powders was used to reduce the diffusive resistance of both the adaxial and abaxial leaf surfaces, and the extent of the disruption to the leaf was investigated with light and electron microscopy. Cuticular abrasion resulted in reduced equilibration times due to decreased cuticular resistance and greater water vapour movement between the leaf and the psychrometer chamber. Equilibration times were reduced from over 5 h in the unabraded control leaves to 1 h with cuticle abrasion. This was associated with the decrease in diffusive resistance with cuticular abrasion from over 55 s cm −1 to less than 8 s cm −1 for both the adaxial and abaxial leaf surfaces. Scanning electron micrographs of the abraded leaf tissue revealed considerable disruption of the stomatal ledge and of the guard cells, surface smoothing and displacement of waxes into the stomatal aperture, and damage to veins. Observations with the transmission electron microscope revealed frequent disruption of epidermal cell walls, and damage to both the cytoplasmic and vacuolar membranes.Read More
Publication Year: 1988
Publication Date: 1988-03-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 6
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