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Ahmad Shirazi and Arthur C. Cameron

A method was developed to measure transpiration rates and apparent water-vapor permeability coefficients (P'H2O) of detached fruit using an analytical balance equipped with a humidity chamber, wide-range humidity-generating and sensing devices, and a datalogger. The system was designed to monitor weight changes with time and, hence, weight loss of individual fruit during exposure to specific relative humidities (RHs) and temperatures. Weight loss was corrected for loss due to respiratory exchange of 02 and CO2 before calculating P'H2O. Values of P'H2O for tomatoes obtained using this method over periods of 5 minutes to 24 hours ranged from 3 to 12 nmol·cm-2·s-1·kPa-1 at 20C, depending on the experimental conditions. These values are similar to previously published values and to those obtained in a conventional weight-loss experiment, which involved intermittent weighing. P'H20 for tomatoes dropped ≈15% in 24 hours. P'H20 increased with a transient increase in RH; the extent of the increase was variable from fruit to fruit, ranging from 5% to 100% over 30% to 90% RH. The change was reversible in that P'H2O increased and decreased within minutes following shifts in RH. Similar changes were found for strawberry P'H20. The increase in P'H2O may be due, in part, to a direct effect of water vapor on the water transport properties of the cuticular polymer and surface temperature depression as a result of evaporative cooling. At 50% RH and 20C, water vapor diffuses from tomatoes 50 times faster than O2 enters on a molar basis. This information will be useful for modeling RH changes in modified-atmosphere packages.

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Thayne Montague, Roger Kjelgren, and Larry Rupp

Growth of woody landscape plants is strongly affected by the underlying surface. In urban areas, plants are subjected to energy balance characteristics of a variety of surfaces. This research investigated energy balance properties of six common urban surfaces: Kentucky bluegrass, pine bark mulch, concrete, asphalt, lava rock mulch, and gravel rock mulch. Each summer over a 2-year period incoming global radiation (GW), relative humidity, and air temperature were measured over each surface, and surface reflectivity (AW), surface temperature (TS), soil temperature (TO), and soil heat flux (SF) were measured below each surface. Thermal conductivity (K) and emitted surface longwave radiation (LW) were also calculated. Surface property differences were determined by regression analysis. Incoming global radiation (independent variable) versus TS, TO, SF, LW data (dependent variable) were analyzed. Linear or quadratic curves were selected according to significance of each variable and the coefficient of determination (R2). Surface reflectivity was greatest for concrete and least for lava rock mulch, and K was greatest for asphalt and concrete and least for lava rock and pine bark mulch. Under maximum GW, regression data indicate that SF and TO would be greatest under asphalt and least under lava rock and pine bark mulch. Under similar circumstances, TS and LW would be greatest for pine bark mulch and least for Kentucky bluegrass. This research revealed that more energy was conducted into the soil below asphalt and concrete, and that a greater portion of GW was prevented from entering the soil below pine bark and lava rock mulch than below other surfaces. Due to these effects, and the lack of evaporative cooling, surface temperatures were greater, and more longwave radiation was emitted from, non-vegetative surfaces than from turf.

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Shigeoki Moritani, Hirotada Nanjo, Atsushi Itou, and Teruki Imai

occurrence of the adiabatic evaporation, the air temperature cannot be allowed to decrease below the wet bulb temperature ( Alkhedhair et al., 2016 ). Consequently, evaporative cooling systems are incapable of significantly decreasing high temperatures that

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Bau-Show Lin and Yann-Jou Lin

“tree” ( Table 4 ). LAI has been reported to affect the cooling properties of plants ( Kumar and Kaushik, 2005 ; Takakura et al., 2000 ; Tanaka and Hashimoto, 2006 ). Larger LAI also had greater evaporation ( Rey, 1999 ) as well as greater

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Susmitha Nambuthiri, Robert L. Geneve, Youping Sun, Xueni Wang, R. Thomas Fernandez, Genhua Niu, Guihong Bi, and Amy Fulcher

evaporative cooling from the porous sidewall material ( Table 2 ). Evaporative cooling also appears to be a factor in reducing substrate heat buildup in WP containers relative to both Plastic and KR containers, which are nonporous ( Table 2 ; Figs. 1 and 2

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Allen V. Barker

. Evaders are animals that avoid the heat, and endurers tolerate the heat. Evaporators are a third class of animals that cool by evaporation of water from their bodies. Size of the animals is important in the strategy employed, with small animals generally

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Brian Makeredza, Michael Schmeisser, Elmi Lötze, and Willem J. Steyn

evaporative cooling in the tree ( Van de Ende, 1999 ). However, little research has been conducted to relate plant water status to sunburn incidence and severity; the link between plant water status and sunburn seems to be based primarily on observations. In a

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Malik G. Al-Ajlouni, Dawn M. VanLeeuwen, and Rolston St. Hilaire

loss from an actively growing field of uniform surface of cool season grass that is ≈12 cm tall and not short of water ( Allen et al., 2005 ) and a crop coefficient ( K c ) are used to calculate plant water budgets. Each crop has a specific coefficient

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Lee F. Johnson, Michael Cahn, Frank Martin, Forrest Melton, Sharon Benzen, Barry Farrara, and Kirk Post

.C. Cooperative Extension ( Cahn et al., 2013 , 2014 ). CM combines crop coefficients and evaporation coefficients with CIMIS ETo to develop irrigation schedules meeting daily crop water requirements of lettuce, broccoli, and other cool-season vegetables. As well

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Peter Juroszek and Hsing-Hua Tsai

(DAT)] and during the cool-dry season from 27 Nov. 2007 to 7 Apr. 2008 (132 DAT). Table 1 shows information on the prevailing air temperature, precipitation, and evaporation. In the first week of Oct. 2007, a typhoon contributed to the unusually high