scholarly journals 197 ENERGY BALANCE OF URBAN SURFACES AFFECTS GAS EXCHANGE OF CRABAPPLE AND NORWAY MAPLE

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 457d-457
Author(s):  
Roger Kjelgren ◽  
Thayne Montague ◽  
Larry Rupp
Keyword(s):  
Thermal Conductivity ◽  
Energy Balance ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Radiation Flux ◽  
Longwave Radiation ◽  
Norway Maple ◽  
Close Proximity ◽  
Air Mixing ◽  
Vapor Pressure Gradient

We investigated gas-exchange response of norway maple and crabapple to the energy balance of turf, bark-mulch, and asphalt surfaces. In each surface stomatal conductance, leaf temperature (T1), and photosynthesis, were measured during two dawn-to-dusk studies concurrent with soil (To), top surface (Ta), and air temperature (Ta) measurements. Different properties affected the energy balance of each surface. Turf transpiration moderated To and Ts while low thermal conductivity of the mulch resulted in To similar to turf but Ts23C higher. Higher thermal conductivity of the asphalt resulted in higher To but Ts intermediate to mulch and turf surfaces. We did not detect differences in Ta, probably due to close proximity to one another that allowed substantial air mixing between treatments. Higher Ts increased longwave radiation flux that raised midday T1 of trees in the mulch and asphalt 3 to 8C higher than trees in the turf. Differences in T1 between the asphalt and mulch were minimal. Stomatal conductance declined with increasing leaf-to-air vapor pressure gradient in all trees, and was consistently lower for trees in the mulch and asphalt through the day due to larger gradients induced by higher T1. Midday photosynthesis was highest for trees in the turf and lowest for those in the mulch. Foliar interception of higher energy fluxes from mulch and asphalt surfaces apparently limited gas exchange in both species due to over-optimal leaf temperatures as compared to trees in the turf

scholarly journals RESPONSE OF FIELD-GROWN NORWAY MAPLE AND GREEN ASH TREES TO WHITE AND BROWN TREESHELTERS

HortScience ◽  
1994 ◽  
Vol 29 (12) ◽  
pp. 1409d-1409
Author(s):  
David T. Montague ◽  
Roger Kjelgren ◽  
Larry Rupp
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Air Temperature ◽  
Tree Growth ◽  
Shoot Elongation ◽  
Wave Radiation ◽  
Green Ash ◽  
Growth Responses ◽  
Ambient Conditions ◽  
Norway Maple

We investigated microclimate, gas exchange, and growth of field-grown Norway maple (Acer platanoides) and green ash (Fraxinus pennsylvanica) trees in brown, white, or no treeshelters. Microclimate, tree growth, and gas exchange measurements were taken summer and winter. Treeshelter microclimate was greenhouse-like compared to ambient conditions, as short-wave radiation (S↓) was lower, and midday air temperature and relative humidity were higher. In both species, this resulted in less trunk growth and greater specific leaf area, which are growth responses characteristic of shade acclimation. Treeshelter microclimate did, however, substantially increase shoot elongation and stomatal conductance, but did not increase photosynthesis when compared to trees grown without shelters. White shelters allowed 25% more penetration of S↓ than brown shelters, but tree growth and climatic variables did not differ with treeshelter color. Stomatal conductance, however, was higher for trees in white shelters. Treeshelters also appeared to have a negative effect on plant hardiness. New shoot growth in shelters was more winter-damaged, particularly in maple, than nonsheltered trees. This may be related to winter bark (Tb) and air temperature (Ta). Winter midday Tb on trees grown in shelters was up to 15C higher than Tb on trees outside shelters, while midday Ta inside treeshelters was up to 20C higher than Ta outside treeshelters.

scholarly journals Surface Energy Balance Affects Gas Exchange and Growth of Two Irrigated Landscape Tree Species in an Arid Climate

2000 ◽  
Vol 125 (3) ◽  
pp. 299-309 ◽  
Author(s):  
Thayne Montague ◽  
Roger Kjelgren ◽  
Larry Rupp
Keyword(s):  
Energy Balance ◽  
Gas Exchange ◽  
Water Loss ◽  
Stomatal Closure ◽  
Longwave Radiation ◽  
Shoot Elongation ◽  
Climatic Conditions ◽  
Leaf Temperature ◽  
Arid Climate ◽  
Growth Data

Research was conducted to investigate how energy balance of bark mulch and turf surfaces influence gas exchange and growth of recently transplanted trees. On several occasions over a 3-year period, stomatal conductance and leaf temperature were measured throughout the day on `Emerald Queen' Norway maple (Acer platanoides L.) and `Greenspire' littleleaf linden (Tilia cordata Mill.) trees growing over each surface. Tree water loss was estimated using a general transport flux equation applied to the tree crown apportioned between sunlit and shade layers. Microclimate variables were measured over each surface with a permanent weather station. Tree growth data were collected at the end of each growing season. Soil heat flux data revealed that a greater portion of incoming radiation was prevented from entering the soil below mulch than below turf. Due to this insulating effect, and consequent lack of evaporative cooling, mulch surface temperature was greater, and emitted more longwave radiation, than turf. Leaves over mulch intercepted more longwave radiation, had greater leaf temperature, and greater leaf-to-air vapor pressure difference than leaves over turf. As a result, leaves over mulch had greater stomatal closure than leaves over turf. Estimated tree water loss varied between surface treatments and with climatic conditions. Trees over turf had greater shoot elongation and leaf area than trees over mulch. These data suggest that gas exchange and growth of recently transplanted trees in an arid climate may be reduced if planted over nonvegetative, urban surfaces.

Parametric Study of Photovoltaic Thermal Solar Collector Using An Improved Parallel Flow

2020 ◽  
Vol 2 (1) ◽  
pp. 19-24
Author(s):  
Sakhr Mohammed Sultan ◽  
Chih Ping Tso ◽  
Ervina Efzan Mohd Noor ◽  
Fadhel Mustafa Ibrahim ◽  
Saqaff Ahmed Alkaff
Keyword(s):  
Thermal Conductivity ◽  
Energy Balance ◽  
Parametric Study ◽  
Solar Collector ◽  
Parallel Flow ◽  
Operating Conditions ◽  
Balance Equations ◽  
Conductivity Type ◽  
Pv Module ◽  
Sunny Weather

Photovoltaic Thermal Solar Collector (PVT) is a hybrid technology used to produce electricity and heat simultaneously. Current enhancements in PVT are to increase the electrical and thermal efficiencies. Many PVT factors such as type of absorber, thermal conductivity, type of PV module and operating conditions are important parameters that can control the PVT performance. In this paper, an analytical model, using energy balance equations, is studied for PVT with an improved parallel flow absorber. The performance is calculated for a typical sunny weather in Malaysia. It was found that the maximum electrical and thermal efficiencies are 12.9 % and 62.6 %, respectively. The maximum outlet water temperature is 59 oC.

Effect of Mycorrhizal Fungi on Gas Exchange of Micropropagated Guava Plantlets (Psidium guajava L.) during Acclimatization and Plant Establishment

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 501c-501
Author(s):  
Andrés A. Estrada-Luna ◽  
Jonathan N. Egilla ◽  
Fred T. Davies
Keyword(s):  
Tissue Culture ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Vapor Pressure ◽  
Mycorrhizal Fungi ◽  
Vapor Pressure Deficit ◽  
Psidium Guajava ◽  
Glomus Etunicatum ◽  
Plant Establishment ◽  
Use Efficiency

The effect of mycorrhizal fungi on gas exchange of micropropagated guava plantlets (Psidium guajava L.) during acclimatization and plant establishment was determined. Guava plantlets (Psidium guajava L. cv. `Media China') were asexually propagated through tissue culture and acclimatized in a glasshouse for eighteen weeks. Half of the plantlets were inoculated with ZAC-19, which is a mixed isolate containing Glomus etunicatum and an unknown Glomus spp. Plantlets were fertilized with modified Long Ashton nutrient solution containing 11 (g P/ml. Gas exchange measurements included photosynthetic rate (A), stomatal conductance (gs), internal CO2 concentration (Ci), transpiration rate (E), water use efficiency (WUE), and vapor pressure deficit (VPD). Measurements were taken at 2, 4, 8 and 18 weeks after inoculation using a LI-6200 portable photosynthesis system (LI-COR Inc. Lincoln, Neb., USA). Two weeks after inoculation, noninoculated plantlets had greater A compared to mycorrhizal plantlets. However, 4 and 8 weeks after inoculation, mycorrhizal plantlets had greater A, gs, Ci and WUE. At the end of the experiment gas exchange was comparable between noninoculated and mycorrhizal plantlets.

The Effects of Drought on Leaf Gas Exchange and Growth of Three Species of Herbaceous Perennials

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 540a-540
Author(s):  
K.J. Prevete ◽  
R.T. Fernandez
Keyword(s):  
Drought Stress ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Drought Tolerance ◽  
Transpiration Rate ◽  
Leaf Gas Exchange ◽  
Gas Analysis ◽  
Herbaceous Perennials ◽  
Effects Of Drought ◽  
Analysis System

Three species of herbaceous perennials were tested on their ability to withstand and recover from drought stress periods of 2, 4, and 6 days. Eupatorium rugosum and Boltonia asteroides `Snowbank' were chosen because of their reported drought intolerance, while Rudbeckia triloba was chosen based on its reported drought tolerance. Drought stress began on 19 Sept. 1997. Plants were transplanted into the field the day following the end of each stress period. The effects of drought on transpiration rate, stomatal conductance, and net photosynthetic rate were measured during the stress and throughout recovery using an infrared gas analysis system. Leaf gas exchange measurements were taken through recovery until there were no differences between the stressed plants and the control plants. Transpiration, stomatal conductance, and photosynthesis of Rudbeckia and Boltonia were not affected until 4 days after the start of stress. Transpiration of Eupatorium decreased after 3 days of stress. After rewatering, leaf gas exchange of Boltonia and Rudbeckia returned to non-stressed levels quicker than Eupatorium. Growth measurements were taken every other day during stress, and then weekly following transplanting. Measurements were taken until a killing frost that occurred on 3 Nov. There were no differences in the growth between the stressed and non-stressed plants in any of the species. Plants will be monitored throughout the winter, spring, and summer to determine the effects of drought on overwintering capability and regrowth.

scholarly journals Normal Cyclic Variation in CO2 Concentration in Indoor Chambers Decreases Leaf Gas Exchange and Plant Growth

Plants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 663
Author(s):  
James Bunce
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Leaf Gas Exchange ◽  
Genetic Material ◽  
Co2 Concentration ◽  
Cyclic Variation ◽  
Indoor Exposure ◽  
Elevated Atmospheric Co2 ◽  
Gas Exchange System ◽  
Opening And Closing

Attempts to identify crop genetic material with larger growth stimulation at projected elevated atmospheric CO2 concentrations are becoming more common. The probability of reductions in photosynthesis and yield caused by short-term variation in CO2 concentration within elevated CO2 treatments in the free-air CO2 enrichment plots raises the question of whether similar effects occur in glasshouse or indoor chamber experiments. These experiments were designed to test whether even the normal, modest, cyclic variation in CO2 concentration typical of indoor exposure systems have persistent impacts on photosynthesis and growth, and to explore mechanisms underlying the responses observed. Wheat, cotton, soybeans, and rice were grown from seed in indoor chambers at a mean CO2 concentration of 560 μmol mol−1, with “triangular” cyclic variation with standard deviations of either 4.5 or 18.0 μmol mol−1 measured with 0.1 s sampling periods with an open path analyzer. Photosynthesis, stomatal conductance, and above ground biomass at 20 to 23 days were reduced in all four species by the larger variation in CO2 concentration. Tests of rates of stomatal opening and closing with step changes in light and CO2, and tests of responses to square-wave cycling of CO2 were also conducted on individual leaves of these and three other species, using a leaf gas exchange system. Reduced stomatal conductance due to larger amplitude cycling of CO2 during growth occurred even in soybeans and rice, which had equal rates of opening and closing in response to step changes in CO2. The gas exchange results further indicated that reduced mean stomatal conductance was not the only cause of reduced photosynthesis in variable CO2 conditions.

Boron Supply and Water Deficit Consequences in Young Paricá (Schizolobium parahyba var. amazonicum) Plants

2016 ◽  
Vol 44 (1) ◽  
pp. 250-256 ◽  
Author(s):  
Bianca do Carmo SILVA ◽  
Pêola Reis de SOUZA ◽  
Daihany Moraes CALLEGARI ◽  
Vanessa Ferreira ALVES ◽  
Allan Klynger da Silva LOBATO ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Water Use Efficiency ◽  
Water Deficit ◽  
Water Use ◽  
Electrolyte Leakage ◽  
Tolerance Mechanism ◽  
Schizolobium Parahyba ◽  
Use Efficiency

Boron (B) is a very important nutrient required by forest plants; when supplied in adequate amounts, plants can ameliorate the negative effects of abiotic stresses. The objective of this study was to (i) investigate gas exchange, (ii) measure oxidant and antioxidant compounds, and (iii) respond how B supply acts on tolerance mechanism to water deficit in young Schizolobium parahyba plants. The experiment employed a factorial that was entirely randomised, with two boron levels (25 and 250 µmol L-1, simulating conditions of sufficient B and high B, respectively) and two water conditions (control and water deficit). Water deficit induced negative modifications on net photosynthetic rate, stomatal conductance and water use efficiency, while B high promoted intensification of the effects on stomatal conductance and water use efficiency. Hydrogen peroxide and electrolyte leakage of both tissues suffered non-significant increases after B high and when applied water deficit. Ascorbate levels presented increases after water deficit and B high to leaf and root. Our results suggested that the tolerance mechanism to water deficit in young Schizolobium parahyba plants is coupled to increases in total glutathione and ascorbate aiming to control the overproduction of hydrogen peroxide and alleviates the negative consequences on electrolyte leakage and gas exchange. In relation to B supply, this study proved that sufficient level promoted better responses under control and water deficit conditions.

scholarly journals Improving the quality of alumina-containing sinter using water-cooled furnace shell

2012 ◽  
Vol 44 (3) ◽  
pp. 281-286
Author(s):  
A.V. Aleksandrov ◽  
V.V. Aleksandrov
Keyword(s):  
Thermal Conductivity ◽  
Steady State ◽  
Heat Exchange ◽  
Energy Balance ◽  
Cold Water ◽  
Sintering Temperature ◽  
Radiant Heat ◽  
Thermal Processes ◽  
Technical Solutions

This article deals with the use of computer modeling to develop technical solutions to ensure better quality of alumina-containing sinter. The simulation accounted for the influence of the feed materials on the thermal processes in the furnace. The energy balance (including thermal conductivity, heat convection and radiant heat exchange) was solved assuming steady state. A good correlation was observed for the actual and calculated temperatures of the solids and gases, with less than 15% discrepancy. Using the model of the furnace investigated the possibility of lowering the temperature of sintering by removing heat from the outside of the furnace shell. To reduce the sintering temperature to 1000 ?C length of the refractory lined steel is 5 m, the height of the lining should not exceed - 0.06 m, the required rate of cold water - 54.7 m3/h

scholarly journals Gas exchanges and photosynthetic efficiency in sub-forest species from Atlantic Forest

2020 ◽  
Vol 9 (5) ◽  
pp. e43952870
Author(s):  
Magnólia Martins Alves ◽  
Manoel Bandeira de Albuquerque ◽  
Renata Ranielly Pedroza Cruz ◽  
Mário Luiz Farias Cavalcanti
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Water Use ◽  
Co2 Concentration ◽  
Time Of Day ◽  
Forest Understory ◽  
Forest Species ◽  
Gas Exchanges ◽  
Endogenous Factors ◽  
Intrinsic Efficiency

The availability of light is one of the factors that most limits the photosynthesis of juvenile trees in the understory of the forest. The study was carried out in the Mata do Pau-Ferro State Park, located in the city of Areia, PB. The objective of this study was to evaluate how gas exchanges occur in individuals of Psychotria colorata (Willd. Ex Roem & Schult.), Senna georgica Irwin & Barneby, Himatanthus phagedaenicus (Mart.) Woodson, Solanum swartzianum Roem. & Schult, Psychotria carthagenensis Jacq.e Psychotria hoffmannseggiana (Willd. ex Schult.) in the understory of a remnant of Mata Atlântica. The rate of photosynthesis (A), transpiration (E), stomatal conductance (Gs), internal CO2 concentration (Ci) leaf temperature-air temperature (°C), and internal carbon (Ci), instantaneous efficiency of water use (EUA) (A/E), Intrinsic efficiency of water use (EiUC) (A/Gs) and the intrinsic efficiency of carboxylation (ratio A/Ci). The rates of maximum photosynthesis (A), photosynthesis (E) and stomatal conductance (Gs) were shown to be influenced by the time of day, as there was no interference of external factors in the diurnal patterns of gas exchange, variations are due to endogenous factors, probably due to the circadian rhythm. The parameter of the gas exchange of sub-forest species responds differently, in the small variations in the luminosity levels of the forest understory

scholarly journals Growth and gas exchange of corn under salt stress and nitrogen doses

2021 ◽  
Vol 25 (3) ◽  
pp. 174-181
Author(s):  
Henderson C. Sousa ◽  
Geocleber G. de Sousa ◽  
Carla I. N. Lessa ◽  
Antonio F. da S. Lima ◽  
Rute M. R. Ribeiro ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Leaf Area ◽  
Plant Height ◽  
Saline Water ◽  
Saline Stress ◽  
Low Salinity ◽  
Salinity Water ◽  
Hybrid Maize ◽  
The University

ABSTRACT The excess of salts can affect several processes in the crops, and nitrogen (N) can attenuate the depressive effect of salinity. The objective was to evaluate the influence of nitrogen doses on the growth and gas exchange of corn crop irrigated with saline water. The experiment was conducted from June to September 2019 at the University of International Integration of Afro-Brazilian Lusophony, Redenção, CE, Brazil. The experimental design was completely randomized, in a 2 x 3 factorial scheme (supply water of 0.3 dS m-1 and saline solution of 3.0 dS m-1) and three nitrogen doses, 0, 80, and 160 kg ha-1, corresponding to 0, 50, and 100% of the recommended dose respectively, with six repetitions. At 30 and 45 days after sowing (DAS), plant height, leaf area, number of leaves, photosynthesis, transpiration, and stomatal conductance were evaluated. Saline stress affects plant height, leaf area, photosynthesis, transpiration, and conductance at 30 DAS. The doses of 80 and 160 kg ha-1 provide greater performance in plant height, leaf area, photosynthesis, transpiration, and conductance at 30 DAS. The use of low salinity water and doses of 80 and 160 kg ha-1 were more efficient in terms of plant height, leaf area, photosynthesis, transpiration, and conductance at 45 DAS. The dose of 160 kg ha-1 of N attenuates the harmful effects of salts in AG 1051 hybrid maize plants, providing higher values of photosynthesis, transpiration, and stomatal conductance at 45 DAS when irrigated with water of 3.0 dS m-1.

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