Effect of Nitrogen Content on the Photosynthetic Characteristics of Sunflower Leaves

1993 ◽  
Vol 20 (3) ◽  
pp. 251 ◽  
Author(s):  
DJ Connor ◽  
AJ Hall ◽  
VO Sadras
Keyword(s):  
Nitrogen Content ◽  
Dark Respiration ◽  
Net Photosynthesis ◽  
Leaf Nitrogen ◽  
Mean Value ◽  
Life Cycles ◽  
High Irradiance ◽  
Response Curves ◽  
Unit Leaf ◽  
Wide Range

Photosynthesis-irradiance response curves and leaf nitrogen contents were measured weekly by destructive sampling over the life cycles of leaves 10, 15, 20 and 25 of sunflower plants (cv. Prosol 35) grown in large pots in the open under optimum conditions of temperature and high irradiance. Individual leaf responses were adequately described by a hyperbola of three parameters, viz. Pmax, the rate of photosynthesis in saturating irradiance; R, the rate of dark respiration adjusted for temperature (30�C); and ε, the apparent quantum efficiency of photosynthesis at low irradiance. Pmax (range 0-40 μmol CO2 m-2 s-1) and R (0-4 μmol CO2 m-2 s-1) were non-linearly related to nitrogen content per unit leaf area (NL) (range 0.3-2.9 g N m-2) across all leaf positions and for all leaf ages. ε (mean value 0.050 mol mol-1, s.e. 0.001) was independent of NL. The equations for net photosynthesis derived from pot studies were shown to explain (r2 =0.80) leaf photosynthesis in a crop of the same cultivar over a wide range of NL and irradiance.

scholarly journals Physiological responses of two tropical weeds to shade: II. Leaf gas exchange and nitrogen content

1999 ◽  
Vol 34 (6) ◽  
pp. 952-961 ◽  
Author(s):  
Moacyr Bernardino Dias-Filho
Keyword(s):  
Nitrogen Content ◽  
Weed Management ◽  
Dark Respiration ◽  
Leaf Gas Exchange ◽  
Co2 Assimilation ◽  
Leaf Nitrogen ◽  
High Irradiance ◽  
Leaf Nitrogen Content ◽  
Light Regimes ◽  
Stachytarpheta Cayennensis

Ipomoea asarifolia (Desr.) Roem. & Schultz (Convolvulaceae) and Stachytarpheta cayennensis (Rich) Vahl. (Verbenaceae), two weeds found in pastures and crop areas in the Brazilian Amazonia, Brazil, were grown in controlled environment cabinets under high (800-1000 µmol m-² s-¹) and low (200-350 µmol m-² s-¹) light regimes during a 40-day period. The objective was to determine the effect of shade on photosynthetic features and leaf nitrogen content of I. asarifolia and S. cayennensis. High-irradiance grown I. asarifolia leaves had significantly higher dark respiration and light saturated rates of photosynthesis than low-irradiance leaves. No significant differences for these traits, between treatments, were observed in S. cayennensis. Low-irradiance leaves of both species displayed higher CO2 assimilation rates under low irradiance. High-irradiance grown leaves of both species had less nitrogen per unit of weight. Low-irradiance S. cayennensis had more nitrogen per unit of leaf area than high-irradiance plants; however, I. asarifolia showed no consistent pattern for this variable through time. For S. cayennensis, leaf nitrogen content and CO2 assimilation were inversely correlated to the amount of biomass allocated to developing reproductive structures. These results are discussed in relation to their ecological and weed management implications.

Partitioning of Nitrogen Between and Within Leaves Grown Under Different Irradiances

1989 ◽  
Vol 16 (6) ◽  
pp. 533 ◽  
Author(s):  
JR Evans
Keyword(s):  
Nitrogen Content ◽  
Photosynthetic Rate ◽  
Protein Complexes ◽  
Leaf Nitrogen ◽  
High Irradiance ◽  
Leaf Nitrogen Content ◽  
Unit Leaf ◽  
Growth Irradiance ◽  
Pigment Protein Complexes ◽  
Nitrogen Contents

The distribution of nitrogen between leaves on individual plants of Phaseolus vulgaris and Cucumis sativus which were grown under different irradiances was examined. For Phaseolus, shading treatments were imposed on individual leaflets when they had reached one-third of full expansion. Adjacent leaflets were either grown under the same irradiance or had different irradiances imposed on them. The nitrogen content of leaves depended on their growth irradiance and not on the growth irradiance of adjacent leaflets, with more nitrogen being found in leaves grown under higher irradiance compared to those grown in shade. For Cucumis, the nitrogen contents of the leaves changed following the imposition of shading treatments. The experiment was repeated four times with different nitrate nutrient treatments, twice in combination with a pretreatment growth irradiance of 40% sunlight. The relative changes in leaf nitrogen content for each irradiance treatment were independent of changes to the leaf nitrogen content of the plant and of the growth irradiance prior to the shading treatments. Again, nitrogen contents were highest in leaves grown at high irradiance. Acclimation of individual leaves to their irradiance treatment was seen for both Phaseolus and Cucumis. Growth under shade resulted in lower rates of oxygen evolution per unit of chlorophyll, when measured at high irradiance, and increased partitioning of nitrogen into pigment-protein complexes. These two changes working in opposition to each other meant that for Cucumis, the relationship between photosynthetic capacity and nitrogen content was similar between irradiance treatments. For Phaseolus, the increased partitioning of nitrogen into pigment-protein complexes at low irradiance was not as great as the reduction in photosynthetic rate per unit of chlorophyll, so that the photosynthetic rate per unit leaf nitrogen was less for leaves grown under low irradiance compared to those grown under high irradiance. It is shown that acclimation to lower irradiance can increase the potential daily photosynthesis for a given leaf nitrogen content.

scholarly journals Short-term Temperature Change Affects the Carbon Exchange Characteristics and Growth of Four Bedding Plant Species

2003 ◽  
Vol 128 (1) ◽  
pp. 100-106 ◽  
Author(s):  
Marc W. van Iersel
Keyword(s):  
Growth Rate ◽  
Dark Respiration ◽  
Net Photosynthesis ◽  
Tagetes Patula ◽  
Short Term ◽  
Response Curves ◽  
Gross Photosynthesis ◽  
Bedding Plants ◽  
Bedding Plant ◽  
Wide Range

Bedding plants are exposed to a wide range of environmental conditions, both during production and in the landscape. This research compared the effect of short-term temperature changes on the CO2 exchange rates of four popular bedding plants species. Net photosynthesis (Pnet) and dark respiration (Rdark) of geranium (Pelargonium ×hortorum L.H. Bail.), marigold (Tagetes patula L.), pansy (Viola ×wittrockiana Gams.), and petunia (Petunia ×hybrida Hort. Vilm.-Andr.) were measured at temperatures ranging from 8 to 38 °C (for Pnet) and 6 to 36 °C (for Rdark). Net photosynthesis of all species was maximal at 14 to 15 °C, while Rdark of all four species increased exponentially with increasing temperature. Gross photosynthesis (Pgross) was estimated as the sum of Pnet and Rdark, and was greater for petunia than for the other three species. Gross photosynthesis was less sensitive to temperature than either Pnet or Rdark, suggesting that temperature effects on Pnet were caused mainly by increased respiration at higher temperatures. Gas exchange-temperature response curves were not useful in determining the heat tolerance of these species. There were significant differences among species in the estimated Rdark at 0 °C and the Q10 for Rdark. Differences in the Q10 for Rdark were related to growth rate and plant size. Large plants had a greater Q10 for Rdark, apparently because these plants had a higher ratio of maintenance to growth respiration than small plants. The Q10 of the maintenance respiration coefficient was estimated from the correlation between the Q10 and relative growth rate, and was found to be 2.5 to 2.6.

scholarly journals The Relationship between Leaf Nitrogen Content and Photosynthesis in Apple Leaves

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 578c-578
Author(s):  
Lailiang Cheng ◽  
Sunghee Guak ◽  
Leslie H. Fuchigami
Keyword(s):  
Nitrogen Content ◽  
Net Photosynthesis ◽  
Leaf Nitrogen ◽  
Leaf Nitrogen Content ◽  
Nitrogen And Phosphorus ◽  
N Content ◽  
Wide Range ◽  
Leaf N Content ◽  
The Relationship ◽  
Leaf N

Fertigation of young Fuji/M26 apple trees (Malus domestica Borkh.) with different nitrogen concentrations by using a modified Hoagland solution for 6 weeks resulted in a wide range of leaf nitrogen content in recently expanded leaves (from 0.9 to 4.4 g·m–2). Net photosynthesis at ambient CO2, carboxylation efficiency, and CO2-saturated photosynthesis of recently expanded leaves were closely related to leaf N content expressed on both leaf area and dry weight basis. They all increased almost linearly with increase in leaf N content when leaf N < 2.4 g·m–2, leveled off when leaf N increased further. The relationship between stomatal conductance and leaf N content was similar to that of net photosynthesis with leaf N content, but leaf intercellular CO2 concentration tended to decrease with increase in leaf N content, indicating non-stomatal limitation in leaves with low N content. Photosynthetic nitrogen use efficiency was high when leaf N < 2.4 g·m–2, but decreased with further increase in leaf N content. Due to the correlation between leaf nitrogen and phosphorus content, photosynthesis was also associated with leaf P content, but to a lesser extent.

The morphological basis of variation in net photosynthetic and respiratory responses of the mat-forming lichen species Stereocaulon virgatum and S. tomentosum

1989 ◽  
Vol 67 (1) ◽  
pp. 167-176 ◽  
Author(s):  
D. S. Coxson ◽  
J. Lancaster
Keyword(s):  
Water Vapor ◽  
Dark Respiration ◽  
Cloud Forest ◽  
A Priori ◽  
Net Photosynthesis ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Response Curves ◽  
Morphological Variations ◽  
Closed Canopy

Response patterns of net photosynthesis and dark respiration are examined in two species of Stereocaulon: S. tomentosum Fr., from early successional pine forest communities of the southern Canadian Rockies, and S. virgatum Ach., an early colonizer in tropical cloud-forest environments. These responses, measured in both intact and dissected mat segments, are described in the context of the influence of morphological variations on patterns of water vapor transport. Saturation response curves are fitted to data, allowing description of maximal rates of both net photosynthesis and dark respiration, water contents at which rates are half maximal, maximal water efficiency, and moisture compensation points. In S. tomentosum the closed-canopy nature of the lichen mat profile results in the development of a distinct shade ecotype in lower thallus segments. This canopy profile also impedes water vapor transport from within the mat profile, creating a more mesic microclimate for photobionts located at depth within the lichen mat. This stands in contrast to the open upper canopy profile of S. virgatum, which allows greater convective exchange at depth and appears to preclude the development of distinct sun–shade photobiont ecotypes. Net photosynthetic activity remains high in fully saturated thalli of S. tomentosum, yet in S. virgatum it is depressed by over 50% at full thallus saturation. This greater depression of photosynthetic uptake at full thallus saturation in the species of the more mesic environment contradicts a priori assumptions based on previous concepts of xeric–mesic response gradients in lichens. These responses are discussed in context of other selective pressures influencing lichen mat morphology.

The ecology of Ramalina menziesii. VI. Laboratory responses of net CO2 exchange to moisture, temperature, and light

1987 ◽  
Vol 65 (1) ◽  
pp. 182-191 ◽  
Author(s):  
U. Matthes-Sears ◽  
T. H. Nash III ◽  
D. W. Larson
Keyword(s):  
Dark Respiration ◽  
Net Photosynthesis ◽  
Co2 Exchange ◽  
Response Curves ◽  
Central California ◽  
Photosynthetic Rates ◽  
Chlorophyll Contents ◽  
The Mean ◽  
The Difference ◽  
Thallus Water Content

The response of net CO2 exchange to thallus water content, thallus temperature, and photosynthetically active radiation was measured in the laboratory for two morphologically different forms of Ramalina menziesii collected from a coastal and an inland habitat in central California. Equations describing the response curves are fitted to the data and compared statistically for the two sites during two seasons. Significant differences were present for all responses both in summer and winter but were more pronounced for net photosynthesis than for dark respiration. The main differences between the two forms were in the absolute rates of net photosynthesis; a maximum of 6.2 was measured for the inland form but only 3.6 mg∙g−1∙h−1 for the coastal form. Chlorophyll contents were also different between the two forms, indicating that chlorophyll is the likely cause for the difference in net photosynthetic rates. Net photosynthetic rates were higher at low temperatures during winter than during summer, but otherwise seasonal variations in the gas exchange responses were relatively minor. Both forms of the lichen are light saturated at quantum fluxes greater than 200 μE∙m−2∙s−1. Both show an optimum temperature for maximum CO2 exchange at 25 °C, well above the mean operating temperature of R. menziesii in the field.

Temperature Response of Whole-plant CO2 Exchange Rates of Magnolia (Magnolia grandiflora L.)

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 511d-511
Author(s):  
Marc W. van Iersel ◽  
Orville M. Lindstrom
Keyword(s):  
Dark Respiration ◽  
Temperature Response ◽  
Net Photosynthesis ◽  
Co2 Exchange ◽  
Limiting Factor ◽  
Response Curves ◽  
Gross Photosynthesis ◽  
Temperature Range ◽  
Whole Plant ◽  
Increasing Temperature

Photosynthesis and respiration temperature-response curves are useful in predicting the ability of plants to perform under different environmental conditions. Whole crop CO2 exchange of two groups of magnolia `Greenback' plants was measured over a 26 °C temperature range. Net photosynthesis (Pnet) increased from 2 to 17% C and decreased again at higher temperatures. The Q10 for Pnet decreased from ≈4 at 6 °C to 0.5 at 24 °C. The decrease in Pnet at temperatures over 17 °C was caused by a rapid increase in dark respiration (Rdark) with increasing temperature. The Q10 for Rdark was estimated by fitting an exponential curve to data, resulting in a temperature-independent Q10 of 2.8. Gross photosynthesis (Pgross), estimated as the sum of Rdark and Pnet, increased over the entire temperature range (up to 25 °C). The Q10 for Pgross decreased with increasing temperature, but remained higher than 1. The data suggest that high respiration rates may be the limiting factor for growth of magnolia exposed to high temperatures, since it may result in a net carbon loss from the plants. At temperatures below 5 °C, both Pnet and Rdark become low and the net CO2 exchange of the plants would be expected to be minimal.

REVIEW Towards an explanation of crop nitrogen demand based on the optimization of leaf nitrogen per unit leaf area

1997 ◽  
Vol 128 (4) ◽  
pp. 377-396 ◽  
Author(s):  
D. J. C. GRINDLAY
Keyword(s):  
Plant Nutrition ◽  
Leaf Nitrogen ◽  
Plant Science ◽  
Potential Growth ◽  
Physiological Basis ◽  
Unit Leaf ◽  
Wide Range ◽  
Fertilizer Recommendations ◽  
N Demand ◽  
Nitrogen Demand

An area of plant science that is still uncertain is precisely what determines plants' demand for nitrogen (N), that is the amount of N they need to take up from the soil to meet their requirements for potential growth and synthesis of new tissue. A robust and unequivocal physiological basis from which to determine N demand is lacking. Yet N dominates plant nutrition. No nutrient is needed in larger quantities and, in most environments, no nutrient is in such limiting supply. Knowledge of the factors governing N demand is essential to predict the needs of crops under a wide range of field situations, so that growers can be given more reliable fertilizer recommendations (Greenwood 1982; van Keulen et al. 1989). This is important, not just for economic reasons, but because of the risks to the environment that can arise from the over-application of N fertilizers, in particular the problem of nitrate leaching (Addiscott et al. 1991).

Effects of nutrient amendment and environment on growth and gas exchange for introduced Penniseturn setaceum in Hawaii

1996 ◽  
Vol 74 (2) ◽  
pp. 268-275 ◽  
Author(s):  
David G. Williams ◽  
R. Alan Black
Keyword(s):  
Water Potential ◽  
Altitudinal Gradient ◽  
Dark Respiration ◽  
Nitrogen Concentration ◽  
Resource Limitation ◽  
Net Photosynthesis ◽  
Leaf Nitrogen ◽  
Carbon Uptake ◽  
Lower Altitude ◽  
Nutrient Amendment

We examined the effects of a balanced soil nutrient amendment on photosynthesis, growth, and reproduction for the alien grass Penniseturn setaceum across an altitudinal gradient on the island of Hawaii. Nutrient amendment of plants enhanced aboveground growth, height, and numbers of reproductive tillers and inflorescences similarly across the altitudinal gradient. Nutrient amendment increased aboveground biomass 22 to 25% but had little effect on predawn water potential, leaf nitrogen concentration, or photosynthesis. Leaf nitrogen concentrations declined with altitude (22 ± 0.5 mg/g N at the coastal site; 16 ± 0.1 mg/g N at the subalpine site) and partially compensated for decreases in specific leaf area with altitude. Plants at the subalpine site had high dark respiration rates, low CO2 saturated photosynthetic rates, and low photosynthetic nitrogen use efficiencies compared with plants at lower altitudes. Chilling temperatures or high respiratory rates may limit net carbon uptake and growth for plants at higher altitude relative to plants at lower altitude. Seasonal patterns of net photosynthesis, stomatal conductance, and water potential suggest that drought colimited carbon uptake and growth at the low altitude site. Success of Penniseturn in Hawaii may stem, in part, from its ability to respond morphologically to compensate for heterogeneous nutrient and water availability across different habitats. Keywords: altitude, Hawaii, nutrient amendment, photosynthesis, Penniseturn setaceum, resource limitation.

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