Photosynthesis and Carbon Dioxide Transfer Resistance of Lodgepole Pine Seedlings in Relation to Irradiance, Temperature, and Water Potential

1974 ◽  
Vol 4 (2) ◽  
pp. 201-206 ◽  
Author(s):  
Gary F. Dykstra
Keyword(s):  
Carbon Dioxide ◽  
Water Potential ◽  
Environmental Conditions ◽  
Net Photosynthesis ◽  
Stomatal Resistance ◽  
Transfer Resistance ◽  
Pine Seedlings ◽  
Rate Limiting ◽  
Potential Maximum ◽  
Mesophyll Resistance

Photosynthesis and stomatal and total equivalent mesophyll resistances to CO2 transfer were measured in relation to irradiance, needle temperature, and tree water potential. Maximum rates of net photosynthesis were attained at 380 W m−2 irradiance, 20 °C needle temperature, and the highest tree water potential obtained, ca. −2.5 bars. Stomatal and total mesophyll resistances have a significant rate-limiting role when environmental conditions are less than optimum. Mesophyll resistance was larger than stomatal resistance under all environmental conditions.

Effect of Water Deficit on Carbon Dioxide Exchange and Leaf Elongation Rate of Panicum maximum Var. trichoglume

1976 ◽  
Vol 3 (3) ◽  
pp. 401 ◽  
Author(s):  
MM Ludlow ◽  
TT Ng
Keyword(s):  
Carbon Dioxide ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Net Photosynthesis ◽  
Stomatal Resistance ◽  
Leaf Water ◽  
Carbon Dioxide Exchange ◽  
Leaf Elongation ◽  
Water Deficits ◽  
Water Potentials

The responses of carbon dioxide exchange and leaf elongation of potted P. maximum var. trichoglume plants to water deficits were investigated in controlled environments and outdoors during drying cycles down to -92 bars leaf water potential, The sensitivities of net photosynthesis and leaf elongation to water deficits were similar. The leaf water potentials at which net photosynthesis and elongation ceased (c. -12 bars), and stomatal resistance increased substantially (- 6 bars), were relatively unaffected by nitrogen supply, environmental conditions during growth, and whether plants had previously experienced stress. However, these factors influenced the rate of net photosynthesis, at high leaf water potentials by affecting stomatal resistance and at moderate water potentials by affecting both stomatal and intracellular resistances. Stomata1 resistance was more sensitive than intracellular resistance to water deficits. Dark respiration rate decreased with leaf water potential, and was higher in plants receiving additional nitrogen. At moderate leaf water potentials (-7 to -9 bars), net photosynthesis of this C4 grass exhibited light saturation and rates similar to C3 plants. We suggest that the difference in behaviour of controlled-environment-grown and field-grown plants to water deficits observed with some species is unlikely to be due to differences in the aerial environment, but may result from differences in the rate at which stress develops. The ecological significance and evolution of the C4 syndrome are discussed briefly.

Carbon dioxide transfer resistance as a factor in shade tolerance of tree seedlings

1970 ◽  
Vol 48 (3) ◽  
pp. 453-456 ◽  
Author(s):  
J. E. Wuenscher ◽  
T. T. Kozlowski
Keyword(s):  
Carbon Dioxide ◽  
Acer Saccharum ◽  
Net Photosynthesis ◽  
Tree Seedlings ◽  
Transfer Resistance ◽  
Quercus Velutina ◽  
Light Intensities ◽  
Quercus Species ◽  
Highly Correlated ◽  
Resistance Rates

Net photosynthesis and transpiration rates of single leaves of Quercus velutina Lam., Q. macrocarpa Michx. var. olivaeformis, and Acer saccharum Marsh. were measured at light intensities of 0.03 to 0.24 cal cm−2 min−1 (400–700 mμ). Resistance to water vapor and carbon dioxide transfer were calculated. Net photosynthesis of the Quercus species was not light saturated until light intensity was increased sufficiently to induce complete stomatal opening, indicating possible limitation of CO2 uptake at low light intensities by high CO2 transfer resistance. Rates of light-saturated net photosynthesis of all three species were highly correlated with CO2 transfer resistance.

Differential Gas Exchange Responses of Two Biotypes of Redroot Pigweed to Atrazine

Weed Science ◽  
1976 ◽  
Vol 24 (1) ◽  
pp. 68-72 ◽  
Author(s):  
L. D. West ◽  
T. J. Muzik ◽  
R. E. Witters
Keyword(s):  
Carbon Dioxide ◽  
Gas Exchange ◽  
Photosynthetic Activity ◽  
Guard Cells ◽  
Stomatal Resistance ◽  
Amaranthus Retroflexus ◽  
Redroot Pigweed ◽  
Mesophyll Tissue ◽  
Diffusive Resistance ◽  
Mesophyll Resistance

Differences were shown to exist in photosynthetic rate, transpiration rate, and carbon dioxide leaf diffusive resistance between atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] susceptible (S) and resistant (R) plants of redroot pigweed (Amaranthus retroflexusL.). Chlorbromuron [3-(4-bromo-3-chlorophenyl)-1-methoxy-1-methylurea] and diruon [3-(3,4-dichlorophenyl)-1,1-dimethylurea] were the only herbicides tested that controlled both biotypes, but all of the herbicides except norea [3-(hexahydro-4,7-methanoindan-5-yl)-1,1-dimethylurea] controlled the S biotype. Although photosynthetic activity and transpiration were reduced in both biotypes by atrazine at 50 and 70 ppm, the decline was much greater in the S biotype than in the R biotype and persisted a longer time in the S biotype. Leaf CO2diffusive resistances of the biotypes were increased by atrazine applications. Mesophyll resistance was increased to a greater extent than stomatal resistance suggesting that reduction of photosynthesis is due to a greater effect of atrazine on the mesophyll tissue than on the guard cells.

Carbon dioxide exchange by native Great Plains grasses

1971 ◽  
Vol 49 (8) ◽  
pp. 1341-1345 ◽  
Author(s):  
Robert E. Redmann
Keyword(s):  
Carbon Dioxide ◽  
Soil Respiration ◽  
Water Potential ◽  
Plant Communities ◽  
Great Plains ◽  
Net Photosynthesis ◽  
Moisture Stress ◽  
Bouteloua Gracilis ◽  
Carbon Dioxide Exchange ◽  
Western North Dakota

Carbon dioxide exchange in relation to light and moisture stress was determined for dominants of three grassland plant communities of western North Dakota. These range from Bouteloua gracilis on very dry sites to Stipa viridula on less dry positions to Sporobolus heterolepis in moist ravines. Maximum net photosynthesis of sod transplants ranged from 10 to 12 mg CO2 g−1 h−1 (6 × 104 lx), corrected for soil respiration of about 3 mg CO2 dm−1 h−1. In B. gracilis and S. viridula, net photosynthesis declined steadily to 25% of maximum when moisture stress was increased to −30 bars soil matric water potential. Net photosynthesis declined less rapidly in S. heterolepis when moisture stress increased to −10 bars, but decreased to zero when stress reached −30 bars. The implications regarding distribution of the species are discussed.

Mesophyll resistance to photosynthetic carbon dioxide uptake in leaves: dependence upon stomatal aperture

1984 ◽  
Vol 62 (1) ◽  
pp. 163-165 ◽  
Author(s):  
David F. Parkhurst
Keyword(s):  
Differential Equation ◽  
Carbon Dioxide ◽  
Partial Differential Equation ◽  
Chemical Reaction ◽  
Stomatal Resistance ◽  
Stomatal Aperture ◽  
Plant Leaves ◽  
Carbon Dioxide Uptake ◽  
Photosynthetic Carbon ◽  
Mesophyll Resistance

A model for carbon dioxide uptake by plant leaves, based on the partial differential equation for diffusion with chemical reaction, is used to simulate photosynthesis for various stomatal openings. The results show that not only the "stomatal resistance" but also the commonly calculated "mesophyll resistance" varies when nothing but stomatal aperture is changed. Simplistic uses of the resistance concept (or related conductances) may be more misleading than useful for modelling photosynthesis, because the various resistance components are neither independent nor additive.

Effects of temperature on the photosynthesis–irradiance response curves of newly matured leaves of alfalfa

1977 ◽  
Vol 55 (8) ◽  
pp. 872-879 ◽  
Author(s):  
S. B. Ku ◽  
L. A. Hunt
Keyword(s):  
Carbon Dioxide ◽  
Stomatal Resistance ◽  
Carbon Dioxide Exchange ◽  
Response Curves ◽  
Oxygen Inhibition ◽  
Thermal Environments ◽  
Growth Regime ◽  
Medicago Sativa L ◽  
Effects Of Temperature ◽  
Mesophyll Resistance

Various carbon dioxide exchange characteristics are described for two alfalfa (Medicago sativa L.) genotypes (AT 171 and CC 120) grown at 20:15 °C and 30:25 °C day:night temperatures and 53 nE cm−2 s−1 irradiance (400–700 nm). Growth at 30:25 °C as compared with 20:15 °C resulted in lower net carbon dioxide exchange rates (NCE) for both genotypes when analyzed at 20 °C, but did not cause any sizeable change for CC 120 at 30 °C. Oxygen inhibition of photosynthesis increased with irradiance to 48 nE cm−2 s−1 but either declined or remained constant with further increase in irradiance. Oxygen inhibition was higher at 30 °C than at 20 °C and was not consistently influenced by growth temperature. However, the ratio of oxygen inhibition to carbon dioxide exchange rate in air containing 1% oxygen and the mesophyll resistance were greater with AT 171 grown at 30:25 °C than at 20:15 °C, particularly at high irradiances. NCE measured at 20 °C instead of 30 °C for plants grown at 30:25 °C was reduced to a much more marked extent with CC 120 than with AT 171; this difference was paralleled by a more marked increase in stomatal resistance length (rSL) for CC 120.rSL decreased with an increase in irradiance, was generally higher at 20 °C than at 30 °C, and did not differ between growth temperatures when measured at an irradiance of 116 nE cm−2 s−1 and a temperature equal to the day temperature of the growth regime. The results are discussed in relation to factors responsible for adaptability to different thermal environments.

Recovery After Water Stress of Leaf Gas Exchange in Panicum maximum var. trichoglume

1980 ◽  
Vol 7 (3) ◽  
pp. 299 ◽  
Author(s):  
MM Ludlow ◽  
TT Ng ◽  
CW Ford
Keyword(s):  
Abscisic Acid ◽  
Water Stress ◽  
Water Potential ◽  
Net Photosynthetic Rate ◽  
Net Photosynthesis ◽  
Recovery Phase ◽  
Stomatal Resistance ◽  
Leaf Water ◽  
Rate Of Recovery ◽  
The Relationship

Net photosynthesis of the last fully expanded leaf of P. maximum var. trichoglume was able to recover from leaf water potentials as low as -92 bar. The degree of stress experienced during the single drying cycle did not influence the maximum net photosynthetic rate attained during recovery, but the time taken to reach the maximum increased with the degree of stress experienced. During the first 24 h, the rate of recovery of net photosynthesis was mainly determined by the rate at which the water status improved. Leaves which experienced water potentials less than c. -40 bar had a slower rate of recovery of water potential than less stressed leaves. This was partially offset by higher rates of net photosynthesis. Furthermore, the relationship between leaf water potential and net photosynthesis recorded during the drying cycle was different from those measured during recovery. Thus different relationships must be used in models simulating behaviour during water stress and subsequent recovery. Stomatal resistance exerted greater control than intracellular resistance over net photosynthesis in the recovery phase, irrespective of the water potential before rewatering or whether plants were preconditioned to stress. Although abscisic acid concentration was positively related to leaf water potential and stomatal resistance during the drying cycle, the relationship between abscisic acid concentration and stomatal resistance during recovery was poor or absent. Sucrose and amino-acid nitrogen accumulated during stress and decreased during recovery. However, the level of non- structural carbohydrates or nitrogen compounds in the recovery phase did not appear to influence net photosynthetic rate or its components. In fact, the reverse appeared to occur: the rate of photosynthesis and growth seemed to determine the levels of these compounds.

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