Canopy Temperatures of Barley as Influenced by Morphological Characteristics¹

Abstract

Canopy temperature under a set of environmental conditions is an integrated result of the energy absorption and dissipation mechanisms acting within the canopy. The relative magnitude of these various mechanisms may affect the amount and efficiency of water use. We studied the influence of different morphological features such as plant color, awn length, and waxiness on canopy temperatures of field grown barley (Hordeum vulgare L.). Morphological differences were obtained by using barley lines isogenic for the various features. Canopy temperatures were measured with an infrared thermometer on five different dates within a 21‐day period after heading. Light‐colored plants were significantly cooler (5% level) than normal‐colored plants. Awn length significantly (5% level) affected canopy temperatures of a sixrow variety; awned canopies were cooler than awnless. Awn length did not affect the canopy temperatures of a two‐row variety. Waxiness did not affect canopy temperatures. Calculations indicate that differences in canopy temperatures due to plant morphology could significantly affect water use.

Diurnal Dynamics of Wheat Evapotranspiration Derived from Ground-Based Thermal Imagery

“…Contrastingly, under overcast conditions, the use of spatially-averaged temperatures, based on thermal camera imagery, performs similar. Note that awnless ears (as in this study) respond more rapidly to changes in incoming radiation [73], whereas the presence of awns can cause a different microclimate around the canopy [74,75], restricting a generalization of our observations. Scatter plots indicate the weakest correlation of T rad and T aero,inv during intermittent clouds (Figure 4) when T rad,WE and T rad,mean mostly exceed T aero,inv (cf.…”

Variation in thylakoid proteins and photosynthesis in Syrian landraces of barley

“…The significance of leaf colour for adaptation to different environments has been studied in mutant strains of barley among which isogenic lines with pale leaves showed significantly lower leaf temperatures (Aase, 1971 ;Ferguson et al ., 1973 ;Ferguson, 1974) . The temperature difference exhibited between pale-and normal-green barley was believed to have been mainly the result of increased reflectivity of light from the leaf surface .…”

Morphological and Physiological Traits Associated with Canopy Temperature Depression in Three Closely Related Wheat Lines

“…In the Sonora Desert of California, cooler leaves of desert plants resulted from higher transpiration rates and smaller leaf size (Smith, 1978). In Montana, cooler barley ( Hordeum vulgare L.) canopies were due to light‐colored and awned plants (Ferguson et al, 1973). Leaf orientation was shown to have a major role in soybean ( Glycine max L.) canopy temperature in Ontario, Canada (Stevenson and Shaw, 1971).…”