Temperature and Transpiration Resistances of Xanthium Leaves as Affected by Air Temperature, Humidity, and Wind Speed
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Leaf resistances decreased with increasing temperature, and silicone rubber replicas of leaf surfaces proved that the decrease was due to increased stomatal apertures, and transpiration varied less than would have been predicted on the basis of the water-vapor pressure difference between leaf and air.Abstract:
Transpiration and temperatures of single, attached leaves of Xanthium strumarium L. were measured in high intensity white light (1.2 calories per square centimeter per minute on a surface normal to the radiation), with abundant water supply, at wind speeds of 90, 225, and 450 centimeters per second, and during exposure to moist and dry air. Partitioning of absorbed radiation between transpiration and convection was determined, and transpiration resistances were computed.Leaf resistances decreased with increasing temperature (down to a minimum of 0.36 seconds per centimeter). Silicone rubber replicas of leaf surfaces proved that the decrease was due to increased stomatal apertures. At constant air temperature, leaf resistances were higher in dry than in moist air with the result that transpiration varied less than would have been predicted on the basis of the water-vapor pressure difference between leaf and air.The dependence of stomatal conductance on temperature and moisture content of the air caused the following effects. At air temperatures below 35 C, average leaf temperatures were above air temperature by an amount dependent on wind velocity; increasing wind diminished transpiration. At air temperatures above 35 C, leaf temperatures were below air temperatures, and increasing wind markedly increased transpiration. Leaf temperatures equaled air temperature near 35 C at all wind speeds and in moist as well as in dry air.read more
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Elevation and transpiration: some theoretical considerations with special reference to Mediterranean-type climate
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Wind as an Ecological Factor
TL;DR: In this article, a few fundamental principles underlying the interaction of plant parts with air currents were developed and various consequences for plant physiological ecology were discussed, including the mechanical deformation of the plant by the frictional drag of the moving air.
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Influence of stomatal distribution on transpiration in low‐wind environments
J. R. Foster,William K. Smith +1 more
References
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Journal ArticleDOI
A method of replicating dry or moist surfaces for examination by light microscopy.
TL;DR: The following method consists essentially of taking a primary impression of the surface with a silicone rubber plastic and using this to form secondary transparent replicas to be used for microscopic study of surfaces.
Journal ArticleDOI
Stomatal Responses to Pressure Changes and Interruptions in the Water Supply of Detached Leaves of Zea mays L.
TL;DR: Stomata of Zea mays L. respond to changes in hydrostatic pressure in the water supply of the leaves almost instantaneously and in all leaf parts simultaneously, therefore, the leaf is a hydraulic unit and their aperture is controlled by the water potential in theWater-conducting system.