Leaf photosynthetic characteristics and net primary production of the polar willow (Salix polaris) in a high arctic polar semi-desert, Ny-Ålesund, Svalbard

2002 ◽  
Vol 80 (11) ◽  
pp. 1193-1202 ◽  
Author(s):  
Hiroyuki Muraoka ◽  
Masaki Uchida ◽  
Masako Mishio ◽  
Takayuki Nakatsubo ◽  
Hiroshi Kanda ◽  
...  
Keyword(s):  
Primary Production ◽  
Net Primary Production ◽  
Natural Habitat ◽  
Leaf Age ◽  
High Arctic ◽  
Photosynthetic Characteristics ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Salix Polaris ◽  
Temperature Conditions

Photosynthetic characteristics and their leaf-age dependence were examined to estimate ecophysiological effects on net primary production (NPP) of a polar willow (Salix polaris), a dominant dwarf shrub species in a polar semi-desert area of Ny-Ålesund, Svalbard. Leaves of S. polaris emerged just after snowmelt in early July in 2000; flowers were initiated within 1 week, and fruits in late July. Light-saturated rate of photosynthesis and stomatal conductance to water vapor increased rapidly to their maximum values within 1 week after leaf emergence and then decreased gradually. Depending on the leaf age, photosynthetic rates saturated at photosynthetically active photon flux density (PPFD) of 200–400 µmol·m–2·s–1, which is the light level usually available in the natural habitat. Optimum leaf temperature of photosynthesis ranged from 10 to 18°C, while air temperature in the habitat ranged from 8 to 20°C. These light and temperature responses of photosynthesis of S. polaris would be suitable for efficient carbon gain in the natural habitat characterized by highly variable light and temperature conditions. Using the photosynthetic and respiratory characteristics, biomass distribution, and meteorological data, NPP of S. polaris in the current year was estimated to be 26.1 g C·m–2. A model simulation of rising temperature conditions predicted a reduction of NPP because of a large increase in respiration. It was suggested that temperature condition and leaf phenological aspects strongly influence the carbon fixation by plants in the high arctic area studied.Key words: arctic semi-desert, climate change, net ecosystem production (NEP), net primary production (NPP), Salix polaris, photosynthesis.

Effect of leaf age on photosynthesis and transpiration of cassava (Manihot esculenta)

1977 ◽  
Vol 55 (17) ◽  
pp. 2288-2295 ◽  
Author(s):  
M. Aslam ◽  
S. B. Lowe ◽  
L. A. Hunt
Keyword(s):  
Chlorophyll Content ◽  
Manihot Esculenta ◽  
Leaf Age ◽  
Gas Analysis ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Genotypic Differences ◽  
Specific Leaf Weight ◽  
Manihot Esculenta Crantz ◽  
Leaf Weight

The effect of plant and leaf age on CO2-exchange rates (CER) and transpiration rates in 15 genotypes of cassava (Manihot esculenta Crantz) was measured in situ by infrared gas analysis. The plants were grown in a controlled-environment room with a 14-h photoperiod, day–night temperatures of 29–24 °C, and 60–70% relative humidity.Plant age had no effect on leaf CER, whereas transpiration rates in 14-week-old plants were significantly greater than those in 7-week-old plants. Both CER and transpiration rates decreased with leaf age. The decline was negligible when measured at low photosynthetic photon flux density. At saturating light, however, both CER and transpiration rates decreased significantly in most of the genotypes. Significant genotypic differences were observed in the pattern of decline. Both stomatal (rs) and residual (rr) resistances to the diffusion of CO2 increased with leafage in all the genotypes. The relative increase in rr was much greater than the increase in rs. In all the genotypes the ratio rr:rs was greater than unity, suggesting that rr is the major component of the total resistance to photosynthesis. Chlorophyll content and specific leaf weight also varied significantly among the genotypes. However, chlorophyll content decreased and specific leaf weight increased with leaf age.

scholarly journals Intensity of bitterness of processed yerba mate leaves originated in two contrasted light environments

2008 ◽  
Vol 51 (3) ◽  
pp. 569-579 ◽  
Author(s):  
Miroslava Rakocevic ◽  
Moacir José Sales Medrado ◽  
Fernando Lucambio ◽  
Alice Teresa Valduga
Keyword(s):  
Leaf Gas Exchange ◽  
Leaf Age ◽  
Sun Exposure ◽  
Photosynthetic Photon Flux Density ◽  
Leaf Temperature ◽  
Forest Understory ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Ilex Paraguariensis ◽  
Yerba Mate

The bitterness intensity of beverage prepared from the leaves produced on the males and females of yerba mate (Ilex paraguariensis), grown in the forest understory and monoculture, was evaluated. The leaves were grouped by their position (in the crown and on the branch tips) and by the leaf age. The leaf gas exchange, leaf temperature and photosynthetic photon flux density were observed. Inter and intra-specific competition for light and self-shading showed the same effect on yerba mate beverage taste. All the shading types resulted in bitterer taste of the processed yerba mate leaves compared to the leaves originated under the direct sun exposure. The leaves from the plants grown in the monoculture showed less bitterness than those grown in the forest understory. This conclusion was completely opposite to the conventionally accepted paradigm of the yerba mate industries. The leaves from the tips (younger leaves) of the plants grown in the monoculture resulted a beverage of softer taste; the males produced less bitter leaves in any light environment (forest understory or in the crown in monoculture). The taste was related to the photosynthetic and transpiration rate, and leaf temperature. Stronger bitterness of the leaves provided from the shade conditions was related to the decreased leaf temperature and transpiration in the diurnal scale.

Effects of photon flux density on photosynthesis, growth, flowering, and oil content in Boronia

1998 ◽  
Vol 49 (5) ◽  
pp. 791 ◽  
Author(s):  
J. M. Wann ◽  
R. Orifici ◽  
Z. E. Spadek ◽  
J. A. Plummer
Keyword(s):  
Light Intensity ◽  
Flux Density ◽  
Oil Content ◽  
Natural Habitat ◽  
Volatile Oil ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Cut Flowers ◽  
Eucalyptus Marginata ◽  
Full Sunlight

Boronia heterophylla is cultivated for cut flowers and B. megastigma for volatile oil production. Both species are endemic to south-western Western Australia and their natural habitat is often shaded by a canopy of Melaleuca parviflora or Eucalyptus marginata. Shade tents were used to examine the influence of reduced photon flux density (PFD) on photosynthesis, growth, and flower production in B. heterophylla and B. megastigma. Volatile oil content was also examined in B. megastigma. Photosynthesis in field-grown B. heterophylla was saturated at 16·2 µmol CO2/m 2·s under a PFD of 1022 µmol/m 2·s (75% full sunlight). Flower number was highest under 75% full sunlight but the number of harvestable stems was the same under 75% and full sunlight. More flowers were produced by B. megastigma plants grown under 75% full sunlight. Content of α-pinene and limonene decreased with decreasing light intensity, whereas β-ionone and docecyl acetate increased with decreasing light intensity

Effects of periodic fluctuations of photon flux density on anatomical and photosynthetic characteristics of soybean leaves

1987 ◽  
Vol 13 (1) ◽  
pp. 81-89 ◽  
Author(s):  
J. P. Gaudillere ◽  
J. J. Drevon ◽  
J. P. Bernoud ◽  
F. Jardinet ◽  
M Euvrard
Keyword(s):  
Flux Density ◽  
Photosynthetic Characteristics ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Periodic Fluctuations ◽  
Soybean Leaves

Leaf nitrogen distribution in relation to leaf age and photon flux density in dominant and subordinate plants in dense stands of a dicotyledonous herb

Oecologia ◽  
1998 ◽  
Vol 113 (3) ◽  
pp. 314-324 ◽  
Author(s):  
N. P. R. Anten ◽  
K. Miyazawa ◽  
K. Hikosaka ◽  
H. Nagashima ◽  
T. Hirose
Keyword(s):  
Flux Density ◽  
Leaf Age ◽  
Leaf Nitrogen ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Nitrogen Distribution

Nitrate Reduction in Redroot Pigweed (Amaranthus retroflexus) and Common Lambsquarters (Chenopodium album) as a Function of Leaf Age and Photosynthetic Photon Flux Density

Weed Science ◽  
1980 ◽  
Vol 28 (5) ◽  
pp. 484-486
Author(s):  
Chang-Chi Chu ◽  
R. D. Sweet ◽  
J. L. Ozbun ◽  
S. L. Kaplan
Keyword(s):  
Nitrate Reduction ◽  
Chenopodium Album ◽  
Leaf Age ◽  
Photosynthetic Photon Flux Density ◽  
Amaranthus Retroflexus ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Photosynthetic Photon Flux ◽  
Common Lambsquarters ◽  
Redroot Pigweed

Nitrate reduction on a leaf fresh weight basis was measured in common lambsquarters (Chenopodium album L.) and redroot pigweed (Amaranthus retroflexus L.) in individual leaves as a function of the photosynthetic photon flux density (PPFD) under which the plants were grown. Common lambsquarters had greater rates of nitrate reduction than did redroot pigweed regardless of leaf age or PPFD and responded to a significantly greater degree when PPFD was increased, with a proportionately greater increase in nitrate reduction among younger leaves.

Ecophysiological investigations of Usnea antarctica in the maritime Antarctic I. Annual microclimatic conditions and potential primary production

1995 ◽  
Vol 7 (3) ◽  
pp. 251-260 ◽  
Author(s):  
Burkhard Schroeter ◽  
M. Olech ◽  
L. Kappen ◽  
W. Heitland
Keyword(s):  
Primary Production ◽  
Carbon Balance ◽  
Dry Weight ◽  
Photosynthetic Photon Flux Density ◽  
South Shetland Islands ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Daily Maximum ◽  
Annual Carbon ◽  
Moisture Conditions

Photosynthetic photon flux density (PPFD), air relative humidity and thallus temperature (TT) were measured in Usnea antarctica over a period of 12 months at a coastal rock on King George Island, South Shetland Islands. TT had an annual amplitude of c. 54 K with the maximum of +27.4°C recorded in December and minimum of −27.3°C in July. Daily maximum TT exceeded 0°C every month except in June and July when they were below −0.4°C and −1.6°C, respectively. Daily minimum temperatures were always below zero. Diel courses of PPFD showed pronounced seasonal differences between summer (more than 2000 μmol m−2s−1) and winter (less than 50 μmol m−2s−1 in July). Daily sum of PPFD was highest (more than 30 mol m−2d−1) in December and lowest (0.1 mol m−2d−1) in July. A photosynthesis model was used to estimate the potential annual primary production from habitat PPFD and TT. The estimated potential annual carbon balance of U. antarctica was 323 mg CO2 g−1 dry weight y−1 assuming that the lichen was always at optimal moisture. The potential carbon balance indicates that primary production is severely limited by low PPFD and subzero TT in the austral winter. Nevertheless, the PPFD and TT would allow metabolic activity during winter but with a negative carbon balance during May–August. Spring and autumnal months are revealed as probably the most important periods for lichen primary production because PPFD exceeds photosynthetic light compensation point during the daytime and ambient moisture conditions frequently favour a positive carbon balance.

scholarly journals An in situ approach to characterizing photosynthetic gas exchange of rice panicle

2020 ◽  
Author(s):  
Tiangen Chang ◽  
Qing-Feng Song ◽  
Honglong Zhao ◽  
Shuoqi Chang ◽  
Changpeng Xin ◽  
...  
Keyword(s):  
Grain Yield ◽  
Pearson Correlation ◽  
Reproductive Organs ◽  
Photosynthetic Characteristics ◽  
Compensation Point ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Photosynthetic Gas Exchange ◽  
Cereal Breeding

Abstract Background: Photosynthesis of reproductive organs in C3 cereals is generally regarded as important to crop yield. Whereas, photosynthetic characteristics of reproductive organs are much less understood as compared to leaf photosynthesis, mainly due to methodological limitations. To date, many indirect methods have been developed to study photosynthesis of reproductive organs and its contribution to grain yield, such as organ shading, application of herbicides and photosynthetic measurement of excised organs or tissues, which might be intrusive and cause biases. Thus, a robust and in situ approach needs to be developed.Results: Here we report the development of a custom-built panicle photosynthesis chamber (P-chamber), which can be connected to standard infrared gas analyzers to study photosynthetic/respiratory rate of a rice panicle. With the P-chamber, we measured panicle photosynthetic characteristics of seven high-yielding elite japonica, japonica-indica hybrid and indica rice cultivars. Results show that, 1) rice panicle is photosynthetically active during grain filling, and there are substantial inter-cultivar variations in panicle photosynthetic and respiratory rates, no matter on a whole panicle basis, on an area basis or on a single spikelet basis; 2) among the seven testing cultivars, whole-panicle gross photosynthetic rates are 17 – 54 nmol s-1 5 days after heading under photon flux density (PFD) of 2000 μmol (photons) m-2 s-1, which represent some 20-38% of that of the corresponding flag leaves; 3) rice panicle photosynthesis has higher apparent CO2 compensation point, light compensation point and apparent CO2 saturation point, as compared to that of a typical leaf; 4) there is a strong and significant positive correlation between gross photosynthetic rate 5 days after heading on a single spikelet basis and grain setting rate at harvest (Pearson correlation coefficient r = 0.93, p-value < 0.0001). Conclusions: Rice panicle gross photosynthesis is significant, has great natural variation, and plays an underappreciated role in grain yield formation. The P-Chamber can be used as a tool to study in situ photosynthetic characteristics of irregular non-foliar plant organs, such as ears, culms, leaf sheaths, fruits and branches, which is a relatively less explored area in current cereal breeding community.

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