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 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.

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.

The interplay between irrigation and fruiting on branch growth and mortality, gas exchange and water relations of coffee trees

2020 ◽  
Author(s):  
Wellington L Almeida ◽  
Rodrigo T Ávila ◽  
Junior P Pérez-Molina ◽  
Marcela L Barbosa ◽  
Dinorah M S Marçal ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Stomatal Density ◽  
Leaf Gas Exchange ◽  
Water Status ◽  
Co2 Concentration ◽  
Plant Hydraulics ◽  
Branch Growth ◽  
Source To Sink ◽  
Leaf Transpiration

Abstract The overall coordination between gas exchanges and plant hydraulics may be affected by soil water availability and source-to-sink relationships. Here we evaluated how branch growth and mortality, leaf gas exchange and metabolism are affected in coffee (Coffea arabica L.) trees by drought and fruiting. Field-grown plants were irrigated or not, and maintained with full or no fruit load. Under mild water deficit, irrigation per se did not significantly impact growth but markedly reduced branch mortality in fruiting trees, despite similar leaf assimilate pools and water status. Fruiting increased net photosynthetic rate in parallel with an enhanced stomatal conductance, particularly in irrigated plants. Mesophyll conductance and maximum RuBisCO carboxylation rate remained unchanged across treatments. The increased stomatal conductance in fruiting trees over nonfruiting ones was unrelated to internal CO2 concentration, foliar abscisic acid (ABA) levels or differential ABA sensitivity. However, stomatal conductance was associated with higher stomatal density, lower stomatal sensitivity to vapor pressure deficit, and higher leaf hydraulic conductance and capacitance. Increased leaf transpiration rate in fruiting trees was supported by coordinated alterations in plant hydraulics, which explained the maintenance of plant water status. Finally, by preventing branch mortality, irrigation can mitigate biennial production fluctuations and improve the sustainability of coffee plantations.

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.

Corrigendum to: Leaf water use efficiency differs between Eucalyptus seedlings from contrasting rainfall environments

2004 ◽  
Vol 31 (7) ◽  
pp. 757 ◽  
Author(s):  
Dane S. Thomas ◽  
Matthew J. Searson ◽  
Jann P. Conway ◽  
Kelvin D. Montagu
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Water Use Efficiency ◽  
Water Use ◽  
Photosynthetic Capacity ◽  
Leaf Gas Exchange ◽  
Eucalyptus Grandis ◽  
Eucalyptus Species ◽  
Use Efficiency ◽  
Leaf N Content

This study investigates the putative role of thicker leaves in enhancing photosynthetic capacity and water-use efficiency (WUE) of Eucalyptus species native to xeric environments. Three Eucalyptus species, Eucalyptus grandis Hill. (ex Maiden), E. sideroxylon Cunn. (ex Woolls) and E. occidentalis (Endl.), were grown under well-watered or water-limited conditions in a single compartment of a temperature-controlled glasshouse. Eucalyptus grandis is native to a mesic environment while E. sideroxylon and E. occidentalis are native to xeric environments. Leaves of E. sideroxylon and E. occidentalis were thicker and contained more nitrogen (N) on a leaf-area basis than E. grandis. Leaf gas-exchange measurements indicated that the photosynthetic capacity of E. sideroxylon and E.�occidentalis was greater than E. grandis and that stomatal conductance and WUE were negatively correlated. Whole-plant, gas-exchange and carbon-isotope measurements showed that E. sideroxylon and E. occidentalis had lower WUE than E. grandis under both well-watered and water-limited conditions. However, there was no difference in N-use efficiency between species. We suggest that stomatal conductance and leaf N content are functionally linked in these seedlings and conclude that thick leaves can, in some conditions, result in low WUE.

Leaf water use efficiency differs between Eucalyptus seedlings from contrasting rainfall environments

2004 ◽  
Vol 31 (5) ◽  
pp. 441 ◽  
Author(s):  
Matthew J. Searson ◽  
Dane S. Thomas ◽  
Kelvin D. Montagu ◽  
Jann P. Conroy
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Water Use Efficiency ◽  
Water Use ◽  
Photosynthetic Capacity ◽  
Leaf Gas Exchange ◽  
Eucalyptus Grandis ◽  
Eucalyptus Species ◽  
Use Efficiency ◽  
Leaf N Content

This study investigates the putative role of thicker leaves in enhancing photosynthetic capacity and water-use efficiency (WUE) of Eucalyptus species native to xeric environments. Three Eucalyptus species, Eucalyptus grandis Hill. (ex Maiden), E. sideroxylon Cunn. (ex Woolls) and E. occidentalis (Endl.), were grown under well-watered or water-limited conditions in a single compartment of a temperature-controlled glasshouse. Eucalyptus grandis is native to a mesic environment while E. sideroxylon and E. occidentalis are native to xeric environments. Leaves of E. sideroxylon and E. occidentalis were thicker and contained more nitrogen (N) on a leaf-area basis than E. grandis. Leaf gas-exchange measurements indicated that the photosynthetic capacity of E. sideroxylon and E.�occidentalis was greater than E. grandis and that stomatal conductance and WUE were negatively correlated. Whole-plant, gas-exchange and carbon-isotope measurements showed that E. sideroxylon and E. occidentalis had lower WUE than E. grandis under both well-watered and water-limited conditions. However, there was no difference in N-use efficiency between species. We suggest that stomatal conductance and leaf N content are functionally linked in these seedlings and conclude that thick leaves can, in some conditions, result in low WUE.

scholarly journals Robust estimates of cuticular conductance to water on a stomatous leaf surface

2021 ◽  
Author(s):  
Jun Tominaga ◽  
Joseph Stinziano ◽  
David T. Hanson
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Simple Technique ◽  
Leaf Surface ◽  
Leaf Gas Exchange ◽  
Stomatal Closure ◽  
Rapid Screening ◽  
Induction Phase ◽  
Robust Estimates ◽  
Co Concentration

In leaf gas exchange measurements, cuticular conductance to water (g) is indistinguishable from and included in stomatal conductance to water vapor (g). Here we developed a simple technique to isolate g by directly measuring leaf intercellular CO concentration (C) along with gas exchange during photosynthetic light induction. We derived stomatal conductance to CO (g) from the C independently of g. Plotting g against g during the early induction phase within ~10 min, we found a highly linear relationship with a positive intercept. Assuming negligible cuticular CO transport, complete stomatal closure occurs when g=0. Then, we considered the residual g (i.e., intercept) as g. Indeed, these g estimates succeeded in correcting the calculation. Our technique, owing to its robustness and increased throughput, will allow for more rapid screening of crops, more reliable gas exchange analysis, and more accurate prediction of plant function under natural environmental conditions.

Seasonal and diurnal patterns in leaf gas exchange of Eucalyptusglobulus trees growing in Portugal

1986 ◽  
Vol 16 (2) ◽  
pp. 177-184 ◽  
Author(s):  
J. S. Pereira ◽  
J. D. Tenhunen ◽  
O. L. Lange ◽  
W. Beyschlag ◽  
A. Meyer ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Leaf Gas Exchange ◽  
Carbon Assimilation ◽  
Net Photosynthesis ◽  
Severe Drought ◽  
Midday Depression ◽  
Diurnal Patterns ◽  
Use Efficiency ◽  
Photosynthetic Carbon Assimilation

Gas exchange of adult leaves of Eucalyptusglobulus Labill. trees growing in Portugal was monitored during weekly periods between September 1982 and August 1983. Photosynthetic carbon assimilation rates and leaf water use efficiency were highest (maximum instantaneous values, ca. 12 μmol CO2 m−2 s−1 and ca. 7 mmol CO2 mol H2O−1, respectively) in the spring, somewhat reduced in the winter, and strongly depressed by the middle of the summer, when severe drought conditions prevailed. Diurnal patterns of variation in stomatal conductance and net photosynthesis rates showed a marked seasonal variation. With the transition from winter to spring and summer, as the environmental conditions became warmer and drier, there was an increasing tendency for a midday depression in gas exchange rates as well as a decreasing capacity in the afternoon for recovery to the same net photosynthesis rates measured in the morning. Midday depression in gas exchange and stomatal conductance occurred in leaves positioned both vertically and horizontally inside the measurement cuvettes. Leaf dark respiratory rates also changed with the season; the temperature necessary to evoke similar rates increased with the transition from winter to summer.

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.

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