Gas Exchange of Mitchell Grass (Astrebla lappacea (Lindl.) Domin) in Relation to Irradiance, Carbon Dioxide Supply, Leaf Temperature and Temperature History

1976 ◽  
Vol 3 (4) ◽  
pp. 471 ◽  
Author(s):  
D Doley ◽  
DJ Yates
Keyword(s):  
Dark Respiration ◽  
Leaf Age ◽  
Net Photosynthesis ◽  
Co2 Concentration ◽  
Light Level ◽  
Leaf Temperature ◽  
Temperature History ◽  
The Best Approximation ◽  
Growth Regime ◽  
Rate Of Photosynthesis

Relationships were established between photosynthesis in A. lappacea and photosynthetic quantum flux, ambient CO2 concentration and leaf temperature. There were no substantial differences between plants raised in a glasshouse and under three temperature regimes in growth cabinets in their responses to light level and CO2 concentration. Large variations in the rate of photosynthesis were observed in plants raised under any environmental regime, this being due in part to the effects of leaf age. It was concluded that the greatest rate of photosynthesis observed in a series of experiments represented the best approximation to the rate attainable in the absence of limitations imposed by factors extraneous to the experiment concerned. The temperature responses of net photosynthesis, dark respiration and transpiration were influenced by growth regime temperature; the leaf temperature at which photosynthesis was maximal increased with growth regime air temperature up to at least 33°C. Plants transferred from one temperature regime to another exhibited the behaviour characteristic of the new regime within one day and two nights of the transfer. Estimates of gas diffusive resistances indicated that both the stornatal and CO2 mesophyll (residual) resistances adapted to changed temperature conditions after about one thermoperiod. The temperatures at which these diffusive resistances were minimal varied in the same sense as the changes in growth regime temperature. The roles of these aspects of behaviour in the adaptation of A. lappacea to its environment are discussed.

Correlation Between the Rates of Foliar Dark Respiration and Net Photosynthesis in Some Tropical Dicot Weeds

Weed Science ◽  
1987 ◽  
Vol 35 (2) ◽  
pp. 141-144 ◽  
Author(s):  
G. Rajendrudu ◽  
J. S. Rama Prasad ◽  
V. S. Rama Das
Keyword(s):  
Respiration Rate ◽  
Dark Respiration ◽  
Leaf Age ◽  
Net Photosynthesis ◽  
Dark Respiration Rate ◽  
Weed Species ◽  
Unit Leaf ◽  
Positive Linear Correlation ◽  
Carbohydrate Levels ◽  
Photosynthetic Type

The rates of foliar dark respiration and net photosynthesis in attached leaves of 25 C3, C4, and C3-C4 intermediate dicotyledonous weed species were determined using the infrared gas analyzer. The ratio of dark respiration to photosynthesis per unit leaf area in attached leaves of each species was inversely proportional to leaf age. Highly significant, positive linear correlation was observed between the rates of foliar dark respiration and net photosynthetic CO2 uptake in dicot weeds irrespective of the photosynthetic type. The higher foliar dark respiration rate found in some of the weed species can be attributed in part to the higher carbohydrate levels as generated by a rapid photosynthetic CO2 assimilation. The significance of higher dark respiration rate in relation to carbon and energy economy of weeds is discussed.

scholarly journals Photosynthesis in Leaves, Fruits, Stem, and Petioles of Tomato Plants Grown in Peat Bags with Different Fertigation Management

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 865A-865
Author(s):  
Hui-lian Xu ◽  
Laurent Gauthier ◽  
André Gosselin
Keyword(s):  
Nutrient Solution ◽  
Photosynthetic Capacity ◽  
Potential Evapotranspiration ◽  
Dark Respiration ◽  
Physiological Activity ◽  
Leaf Age ◽  
Net Photosynthesis ◽  
Tomato Plants ◽  
Use Efficiency ◽  
Leaf P

Tomato plants were grown in peat bags in greenhouse to examine the effects of variation of the nutrient solution electrical conductivity (EC) and substrate water potential (Ψsub) on photosynthesis in leaves, fruits, stem, and petioles. EC of the nutrient solution delivered to peat bags varied between 1 to 4 dS·m–1 with Ψsub of either –5 kPa or –9 kPa as the setpoint for starting the irrigation. The EC variation was adjusted by a computer system according to potential evapotranspiration. Gross photosynthetic capacity (PC) decreased as the leaf age developed. PC in the 10th, 15th and 18th leaves from the top was only 76%, 37%, and 18% of PC in the 5th leaf, respectively. However, low quantum use efficiency (QUE) was only observed in the 18th leaf and low dark respiration (RD) was only in 15th and 18th leaves. Net photosynthesis (PN) was only observed in young fruits (≈10 g FW) or young petioles and no PN was observed in large fruits (50 g or more FW) and stems. Both PC and RD were lower in older fruits and petioles or in the lower part of the stem compared to the younger ones or upper parts. EC variation increased PC, QUE, and RD in most parts. Low Ψsub increased RD in most parts and decreased PC in fruits, stem, and petioles. It is suggested that EC variation increased plant physiological activity of tomato and low Ψsub increased carbon consumption, although it was not severe enough to depress leaf PC.

scholarly journals A Model for Net Photosynthesis of Rose Leaves as a Function of Photosynthetically Active Radiation, Leaf Temperature, and Leaf Age

1990 ◽  
Vol 115 (3) ◽  
pp. 486-491 ◽  
Author(s):  
J.H. Lieth ◽  
C.C. Pasian
Keyword(s):  
Photosynthetically Active Radiation ◽  
Mathematical Description ◽  
Leaf Age ◽  
Net Photosynthesis ◽  
Leaf Temperature ◽  
Rosa Hybrida ◽  
Crop Canopy ◽  
Active Radiation ◽  
The Relationship

A mathematical description for the relationship between the rate of rose (Rosa hybrida L.) leaf net photosynthesis and photosynthetically active radiation, leaf temperature, and leaf age is developed. The model provides a tool for the prediction of these rates for leaves growing in a rose crop canopy.

Leaf temperature effects on net photosynthesis, dark respiration, and photorespiration of seedlings of black locust families with contrasting growth rates

1991 ◽  
Vol 21 (11) ◽  
pp. 1616-1621 ◽  
Author(s):  
Tesfai Mebrahtu ◽  
James W. Hanover ◽  
Desmond R. Layne ◽  
James A. Flore
Keyword(s):  
Growth Rates ◽  
Temperature Effects ◽  
Significant Interaction ◽  
Black Locust ◽  
Dark Respiration ◽  
Net Photosynthesis ◽  
Leaf Temperature ◽  
Gross Photosynthesis ◽  
Sib Families ◽  
Slow Growing

Rates of net photosynthesis, dark respiration, and photorespiration of six half-sib families of black locust (Robiniapseudoacacia L.) were measured at leaf temperatures ranging from 10 to 40 °C. Rates of dark respiration increased with increasing leaf temperature in all families and reached as high as 67% of gross photosynthesis at 40 °C in one family. Dark respiration of foliage accounted for 12.5 to 59% of the reduction in net photosynthesis at temperatures higher than those optimum for net photosynthesis. Rates of photorespiration peaked at 10 to 20 °C, exhibiting the same pattern as net photosynthesis, and did not contribute to the decline in net photosynthesis at high temperatures. The families with high rates of net photosynthesis also had high rates of photorespiration. Rates of dark respiration were significantly different among the families, and the slow-growing families had the highest rates of dark respiration. A significant interaction between half-sib families and leaf temperatures was noted for dark respiration. The data indicated the possibility of improving the growth of black locust by selection and breeding for large leaf area, high rates of net photosynthesis and low rates of dark respiration.

Comparative gas exchange physiology in the Daucus carota complex

1978 ◽  
Vol 56 (15) ◽  
pp. 1739-1743 ◽  
Author(s):  
Ernest Small ◽  
R. L. Desjardins
Keyword(s):  
Gas Exchange ◽  
Water Use ◽  
Daucus Carota ◽  
Dark Respiration ◽  
Net Photosynthesis ◽  
Wild Populations ◽  
Stomatal Frequency ◽  
Rate Of Photosynthesis ◽  
Taxonomic Groups

Rates of net photosynthesis, transpiration, and dark respiration of seven populations representing the diversity of the Daucus carota complex were measured. The two taxonomic groups of this complex proved physiologically distinguishable, with subspecies aggregate gingidium possessing lower capacities for photosynthesis and transpiration and a lower frequency of stomata than subspecies aggregate carota. In comparison with wild populations of the complex, cultivars manifested greater efficiency of photosynthesis with respect to water use, possibly the result of an increased demand for photosynthate in domesticated populations. The highest rate of photosynthesis was exhibited by a vigorous, primitive, Asian cultivar, which also possessed the highest stomatal frequency.

Relationship of Net Photosynthesis to Carbon Dioxide Concentration and Leaf Characteristics in Selected Peanut (Arachis) Genotypes1

1976 ◽  
Vol 3 (1) ◽  
pp. 10-14 ◽  
Author(s):  
A. S. Bhagsari ◽  
R. H. Brown
Keyword(s):  
Wild Species ◽  
Dark Respiration ◽  
Carbon Dioxide Concentration ◽  
Net Photosynthesis ◽  
Co2 Concentration ◽  
Leaf Nitrogen Content ◽  
Leaf Characteristics ◽  
Co2 Concentrations ◽  
Free Air ◽  
Diffusive Resistance

Abstract Five genotypes, including two cultivars of Arachis hypogaea L. and three wild species of Arachis, were tested for their photosynthetic capacity at atmospheric CO2 concentrations and for photorespiration in CO2-free air. Photosynthetic response to CO2 concentrations in the range of 50 to 600 ppm was also tested. Diffusive resistance (DRH2O) of the adaxial surface of the five genotypes was measured with a diffusive resistance porometer. Several other leaf characteristics related to CO2 exchange were measured. There was a linear increase in net photosynthesis (Pn) for four of the five genotypes as CO2 concentration was increased from 50 to 600 ppm. The increase in Pn of an A. hypogaea genotype from Tanganyika appeared to be progressively less at CO2 concentrations near 600 ppm. The florunner cultivar of A. hppogaea had the highest Pn at CO2 concentrations of 300 ppm and above; A. pintoi had the lowest. Photorespiration as measured by CO2 evolution into CO2-free air averaged about 4 mg CO2 dm -2 hr -1 and did not differ among genotypes. Dark respiration was higher in leaves of wild species than in the two genotypes of A. hypogaea. Diffusive resistance of A. hypogaea, A. pintoi and A. sp. (glabrata?) leaves remained constant from 9 a.m. to 3 p.m. EST and then increased up to the last measurement at 10 p.m. The DRH2O of A. hypogaea and A. pintoi were similar during the daytime and ranged from 1.5 to 5.0 sec cm -1 between 9 a.m. and 3 p.m. A. villosulicarpa and A. sp. (glabrata?) had higher DRH2O values during the same time period, ranging from 5 to 12 sec cm-1. At 10 p.m. DRH2O of A. hypogaea was 84 sec cm-1 compared to only about 20 sec cm-1 for A. pintoi. Net photosynthesis of leaves of the five Arachis genotypes was not closely related to DRH2O nor leaf characteristics including chlorophyll content, stomatal frequency, leaf nitrogen content or specific leaf weight.

scholarly journals Photosynthesis of Tropical Pasture Plants III. Leaf Age

1971 ◽  
Vol 24 (4) ◽  
pp. 1077 ◽  
Author(s):  
MM Ludlow ◽  
GL Wilson
Keyword(s):  
Dark Respiration ◽  
Leaf Age ◽  
Gas Analysis ◽  
Controlled Environment ◽  
Tropical Pasture ◽  
Optimum Conditions ◽  
Dark Respiration Rate ◽  
Leaf Ontogeny ◽  
Analysis System ◽  
Pasture Plants

Grass and legume plants were grown under near-optimum conditions in controlled-environment cabinets. Changes in net photosynthetic rate, dark respiration rate, and carbon dioxide transfer resistances during leaf ontogeny, and variability between leaves on grass tillers and legume runners were studied under controlled conditions in an open gas analysis system.

Assimilate Source-Sink Relationships in Capsicum annuum L. III. The Effects of Fruit Excision on Photosynthesis and Leaf and Stem Carbohydrates.

1978 ◽  
Vol 5 (1) ◽  
pp. 1 ◽  
Author(s):  
AJ Hall ◽  
FL Milthorpe
Keyword(s):  
Control Mechanism ◽  
Dark Respiration ◽  
Soluble Sugars ◽  
Co2 Concentration ◽  
Co2 Uptake ◽  
Factors Affecting ◽  
Co2 Compensation Point ◽  
Time Period ◽  
Internal Co2 ◽  
Source Sink

Removal of the rapidly growing fruit from a Capsicum plant reduced the rate of net CO2 uptake by its leaves by up to 30% during the time period explored (0.5 - 7 days). This reduction was associated with increases in both the leaf (to about 200%) and intracellular (to about 30%) resistances, these changes having about equal effects on reducing the rate of CO2 uptake. Changes in photorespiration, dark respiration and CO2 compensation point were very small. The rate of CO2 uptake and the associated resistances were also changed by modifying the light regime and other factors affecting the source-sink balance. Changes in the leaf resistance were not attributable to variations in the internal CO2 concentration or in the water economy of the leaf; its control mechanism remains unexplained. The concentration of soluble sugars in the source leaf was completely unaffected but that of polysaccharides was changed by defruiting and by 50% defoliation. However, variations in the intracellular resistance were not closely related to these changes and there is yet no evidence of the nature of its control mechanism. Changes in both soluble sugars and polysaccharides in the stem were more pronounced than in the leaves.

Photosynthetic response of geranium to elevated CO2 as affected by leaf age and time of CO2 exposure

1991 ◽  
Vol 69 (11) ◽  
pp. 2482-2488 ◽  
Author(s):  
D. W. Kelly ◽  
P. R. Hicklenton ◽  
E. G. Reekie
Keyword(s):  
Stomatal Density ◽  
Leaf Age ◽  
Net Photosynthesis ◽  
Leaf Thickness ◽  
Middle Aged ◽  
Future Studies ◽  
Structural Modifications ◽  
Young Leaves ◽  
Developmental Characteristics ◽  
Density Results

Geranium plants were grown from seed in chambers maintained at 350 or 1000 μL∙L−1 CO2. Phtopsynthesis as affected by leaf age and by leaf position was determined. Elevated CO2 enhanced photosynthesis to the greatest extent in middle-aged leaves; very young leaves exhibited little enhancement, and net photosynthesis in the oldest leaves was depressed by elevated CO2. Temporary increases in net photosynthesis (relative to leaves developed at high CO2) resulted when young leaves grown at 350 μL∙L−1 CO2 were switched to 1000 μL∙L−1 CO2. Leaves switched later in development exhibited permanent enhancement. Middle-aged leaves exhibited a temporary depression followed by permanent enhancement. Leaves developed at high CO2 and switched to low CO2 did not exhibit any photosynthetic depression relative to plants grown continuously at low CO2. Similarly, leaves developed at low CO2, switched to high CO2 for various lengths of time, and returned to low CO2 showed no photosynthetic depression. Leaves developed at low CO2 and switched to high CO2 exhibited increases in specific leaf weight and leaf thickness. The increase in leaf thickness was proportional to length of time spent at high CO2. High CO2 depressed the rate at which stomata developed but did not affect final stomatal density. Results suggest that photosynthesis at low CO2 was limited by CO2 regardless of developmental environment, whereas photosynthesis at high CO2 was limited by the developmental characteristics of the leaf. Further, both biochemical and structural modifications appear to be involved in this response. Because of the very different responses of young versus old leaves, future studies should be careful to consider leaf age in assessing response to elevated CO2. Key words: carbon dioxide, elevated CO2, photosynthesis, geranium.

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