scholarly journals Gas exchange of the umbu tree under semi-arid conditions

2004 ◽  
Vol 26 (2) ◽  
pp. 206-208 ◽  
Author(s):  
José Moacir Pinheiro Lima Filho
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Rainy Season ◽  
Exchange Process ◽  
Co2 Concentration ◽  
Co2 Assimilation ◽  
Internal Co2 ◽  
Gas Exchange Process ◽  
Infrared Gas Analyzer ◽  
Dry And Rainy Seasons

A study was carried out at Embrapa Semi-Árido, Petrolina-PE, Brazil, aiming to understand the gas exchange process of the umbu tree (Spondias tuberosa Arr. Cam.) in the dry and rainy seasons. Stomatal conductance, transpiration, photosynthesis and internal CO2 concentration were obtained with a portable infrared gas analyzer (IRGA). During the dry season the umbu tree showed a much lower stomatal conductance early in the morning, as soon as the vapor pressure deficit increased, apparently affecting CO2 assimilation more than transpiration. The highest values were detected around 6:00 am but decreased to the lowest points between 10:00 am and 2:00 pm. During the rainy season, however, stomatal conductance, transpiration and photosynthesis were significantly higher, reaching the highest values between 8:00 and 10:00 am and the lowest around 2:00 pm. It was also observed at 4:00 pm, mainly during the rainy season, an increase on these variables indicating that the umbu tree exhibits a two-picked daily course of gas exchange.

Another View of Gas Exchange Model: Reflection of Leaf Surface Air to Stomatal Conductance

2010 ◽  
Vol 113-116 ◽  
pp. 14-17
Author(s):  
Meng Hu ◽  
Shao Zhong Kang ◽  
Tai Sheng Du ◽  
Ling Tong
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Leaf Surface ◽  
Leaf Gas Exchange ◽  
Exchange Process ◽  
Negative Relationship ◽  
Co2 Concentration ◽  
Reflection Function ◽  
Use Efficiency ◽  
Gas Exchange Process

A reflection function was established, based on leaf gas exchange process and tested with experimental data of eight kinds of plants, i.e. tomato, muskmelon, capsicum, maize, grape, onion, Haloxylon Ammodendron Bunge and Caragana Karshiskii Kom, with multifarious biological characteristic, water and growing status. The function indicated that the leaf stomatal conductance could be linearly reflected by the ratio of humidity and CO2 concentration at leaf surface, and the behaviour of its slope could be recognized as an indicator of leaf gas exchange efficiency, which had a negative relationship with leaf water use efficiency (WUE). The results maybe increase our understanding of potential influences of leaf stomatal conductance on photosynthetic and transpiration gas exchange and leaf WUE.

scholarly journals Effect of fertigation with potassium and nitrogen on gas exchange and biomass accumulation in eggplant1

2017 ◽  
Vol 47 (3) ◽  
pp. 345-352
Author(s):  
Álvaro Henrique Cândido de Souza ◽  
Roberto Rezende ◽  
Marcelo Zolin Lorenzoni ◽  
Fernando André Silva Santos ◽  
André Maller
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Water Use ◽  
Biomass Accumulation ◽  
Net Photosynthesis ◽  
Dry Weight ◽  
Co2 Concentration ◽  
Internal Co2 ◽  
Use Efficiency ◽  
Total Dry Weight

ABSTRACT Adequate crop fertilization is one of the challenges for agriculture. Measuring gas exchange and biomass accumulation may be used to adjust crop management. The effect of fertigation with potassium (0 kg ha-1, 54 kg ha-1, 108 kg ha-1 and 216 kg ha-1) and nitrogen (0 kg ha-1, 67 kg ha-1, 134 kg ha-1 and 268 kg ha-1) on gas exchange and biomass accumulation in eggplant was assessed under greenhouse conditions. The net photosynthesis, stomatal conductance, transpiration, internal CO2 concentration, instantaneous carboxylation efficiency, water-use efficiency and total dry weight were evaluated. With the exception of K for water-use efficiency and N for internal CO2 concentration, all the other gas exchange parameters were significantly affected by the K and N doses. There was an interaction between N and K doses for net photosynthesis, stomatal conductance, transpiration and instantaneous carboxylation efficiency. The highest values for net photosynthesis, stomatal conductance, transpiration rate, carboxylation instantaneous efficiency and total dry weight were found in the range of 125-185 kg ha-1 of K and 215-268 kg ha-1 of N.

scholarly journals Interaction between soil salinity and nitrogen on growth and gaseous exchanges in guava

2018 ◽  
Vol 13 (3) ◽  
pp. 1
Author(s):  
Idelfonso Leandro Bezerra ◽  
Hans Raj Gheyi ◽  
Reginaldo Gomes Nobre ◽  
Geovani Soares de Lima ◽  
João Batista dos Santos ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Leaf Area ◽  
Co2 Concentration ◽  
Co2 Assimilation ◽  
Stem Diameter ◽  
Assimilation Rate ◽  
Gas Exchanges ◽  
Internal Co2 ◽  
N Dose ◽  
Number Of Leaves

This study evaluated the growth and gas exchanges of guava, cv. ‘Paluma’ cultivated in salinized soil and subjected to different nitrogen (N) doses in a protected environment in the municipality of Campina Grande-PB. The experimental design was randomized blocks, in a 5 x 4 factorial arrangement with three replicates, and the treatments resulted from the combination of five salinity levels in the soil saturation extract - ECse (2.15, 3.15,4.15, 5.15 and 6.15 dS m-1) and four N doses (70, 100, 130 and 160% of the recommended N dose). The dose referring to 100% of N corresponded to 541.1 mg of N dm-3 of soil. At 120 and 180 days after (DAT), plant growth was evaluated based on stem diameter (SD), leaf area (LA) and number of leaves (NL). At 210 DAT, the following variables of leaf gas exchanges were evaluated: stomatal conductance (gs), internal CO2 concentration (Ci), transpiration (E) and CO2 assimilation rate (A). ECse above 2.15 dS m-1 reduced stem diameter, leaf area, number of leaves, stomatal conductance, internal CO2 concentration, transpiration and CO2 assimilation rate, in both evaluation periods. N dose above 70% of the recommendation (378.7 mg N dm-3 of soil) did not mitigate the deleterious effects caused by the salt stress on the growth and gas exchanges of guava plants.

scholarly journals PHOTOSYNTHETIC EFFICIENCY OF TOMATO PLANTS SUBMITTED TO CALCIUM SILICATE APPLICATION

2020 ◽  
Vol 7 (4) ◽  
pp. 49-58
Author(s):  
Pablo Wenderson Ribeiro Coutinho ◽  
Márcia De Moraes Echer ◽  
Vandeir Francisco Guimarães ◽  
Maria Do Carmo Lana ◽  
Adriano Mitio Inagaki ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Water Use ◽  
Photosynthetic Pigments ◽  
Calcium Silicate ◽  
Co2 Concentration ◽  
Co2 Assimilation ◽  
Leaf Transpiration ◽  
Full Flowering ◽  
Internal Concentration ◽  
Internal Co2

The objective was to evaluate the effect of calcium silicate on the chlorophyll content and gas exchange of two tomato hybrids. The design used was in randomized blocks in a 2x5 factorial scheme, with four replications. The first factor was composed of two tomato hybrids: Ivety and Natália, and the second factor was composed of five doses of calcium silicate (0, 150, 300, 450, and 600 kg ha-1), applied to the substrate before planting the seedlings. Gas exchange: net CO2 assimilation rate (A), leaf transpiration rate (E), stomatal conductance (gs), internal CO2 concentration (Ci), water-use efficiency (WUE), intrinsic efficiency water use (iWUE), and instant carboxylation efficiency (ACi); SPAD index and the levels of chlorophylls a, b, and total were evaluated. The analyzes were performed in the stages of first flowering (17 days after transplanting - DAT), full flowering (58 DAT), and full fruiting (78 DAT). At 17 DAT, no difference was observed for gas exchange variables and photosynthetic pigments. The application of calcium silicate reduced gas exchange and photosynthetic pigments at 58 DAT. The hybrid Natália had the highest A, WUE, iWUE, and ACi at 78 DAT. However, the hybrid Ivety in the same growth stage, in full fruiting, was superior only for the internal concentration of CO2 and SPAD index, with no difference for photosynthetic pigments.

scholarly journals Photosynthesis of Physalis peruviana under different densities of photons and saline stress

2021 ◽  
Vol 37 ◽  
pp. e37082
Author(s):  
Francisco Romário Andrade Figueiredo ◽  
João Everthon da Silva Ribeiro ◽  
Jackson Silva Nóbrega ◽  
Wilma Freitas Celedônio ◽  
Reynaldo Teodoro de Fátima ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Abiotic Factors ◽  
Block Design ◽  
Co2 Concentration ◽  
Co2 Assimilation ◽  
Saline Stress ◽  
Physalis Peruviana ◽  
Randomized Block Design ◽  
Liquid Co2 ◽  
Internal Co2

Physalis peruviana L. is a solanacea that has been gaining prominence due to its fruits presenting good acceptance in the national and international market. However, several abiotic factors, such as salinity, can cause physiological disturbances in plants, and these changes may be of greater or lesser intent according to species. Therefore, the objective of the present work was to evaluate the physiological behavior of P. peruviana submitted to different fluxes of photosynthetically active photons (PPFD) and saline stress. The experimental design was a randomized block design with three saline levels (ECw) (0.5, 2.75 and 5.00 dS m-1) with four replications. Gas exchange measurements were performed with a portable infrared gas analyzer. Liquid CO2 assimilation, stomatal conductance, internal CO2 concentration, water use efficiency and instantaneous carboxylation efficiency were measured. Data were subjected to analysis of variance by F test and in cases of significance applied to regression analysis. The increase in PPFD provided reductions in stomatal conductance up to the density of approximately 400 μmol m-2s-1, being more pronounced in ECw of 2.75 and 5.0 dS m-1. The maximum CO2 assimilation rates in the three salinities are different according to the PPFD. The salinity of irrigation water reduced the quantum efficiency of photosynthesis in P. peruviana plants.

scholarly journals Physiological attributes of jatropha under different planting densities and nitrogen doses

2016 ◽  
Vol 20 (12) ◽  
pp. 1112-1117 ◽  
Author(s):  
Allan R. F. Campos ◽  
Rosiane L. S. de Lima ◽  
Carlos A. V. de Azevedo ◽  
Ronaldo do Nascimento ◽  
Sonivagno S. Silva
Keyword(s):  
Stomatal Conductance ◽  
Photosynthetic Activity ◽  
Co2 Concentration ◽  
Co2 Assimilation ◽  
N Fertilization ◽  
The Other ◽  
Planting Density ◽  
Assimilation Rate ◽  
Internal Co2 ◽  
Use Efficiency

ABSTRACT Nitrogen (N) fertilization associated with planting density is a practice that can improve the physiological aspects and consequently increase the yield of a crop. Thus, this study aimed to evaluate the effects of planting density and N levels on the physiological aspects of jatropha in the ‘Agreste’ region of Paraíba. Treatments consisted of four planting densities (833, 1,111, 1,666 and 2,500 plants ha-1) representing the plots and five N doses (0, 40, 80, 120 and 180 kg ha-1) corresponding the subplots. The effects of treatments on CO2 assimilation rate, internal CO2 concentration, transpiration, stomatal conductance, water use efficiency, instantaneous carboxylation efficiency and SPAD index were analysed. Except for stomatal conductance, the other variables were influenced by the interaction between planting densities and N levels. The association of the dose of 80 kg ha-1 with a planting density of 2,200 plants ha-1 provided adequate conditions for the production of plants with increased photosynthetic activity and efficient use of water.

Experimental research on scavenging process of opposed-piston two-stroke gasoline engine based on tracer gas method

2021 ◽  
pp. 146808742110366
Author(s):  
Fukang Ma ◽  
Wei Yang ◽  
Yifang Wang ◽  
Junfeng Xu ◽  
Yufeng Li
Keyword(s):  
Gas Exchange ◽  
Exchange Process ◽  
Delivery Ratio ◽  
Tracer Gas ◽  
Piston Motion ◽  
Trapped Air ◽  
Exchange Performance ◽  
Gdi Engine ◽  
Gas Exchange Process ◽  
Scavenging Efficiency

The scavenging process of two stroke engine includes free exhaust, scavenging, and post intake process, which clears the burned gas in cylinder and suctions the fresh air for next cycle. The gas exchange process of Opposed-Piston Two-Stroke (OP2S) engine with gasoline direct injection (GDI) engine is a uniflow scavenging method between intake port and exhaust port. In order to investigate the characteristics of the gas exchange process in OP2S-GDI engine, a specific tracer gas method (TGM) was developed and the experiments were carried out to analyze the gas exchange performance under different intake and exhaust conditions and opposed-piston movement rule. The results show that gas exchange performance and trapped gas mass are significantly influenced by intake pressure and exhaust pressure. And it has a positive effect on the scavenging efficiency and the trapped air mass. Scavenging efficiency and trapped air mass are almost independent of pressure drop when the delivery ratio exceeds 1.4. Consequently, the delivery ratio ranges from 0.5 to 1.4 is chosen to achieve an optimization of steady running and minimum pump loss. The opposed piston motion phase difference only affects the scavenging timing. Scavenging performance is mainly influenced by scavenging timing and scavenging duration. With the increased phase difference of piston motion, the scavenging efficiency and delivery ratio increased gradually, the trapping efficiency would increase first and decrease then and reaches its maximum at 14°CA.

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.

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

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