Effects of photosynthetic models on the calculation results of photosynthetic response parameters in young Larix principis-rupprechtii Mayr. plantation

Accurately predicting the crown photosynthesis of trees is necessary for better understanding the C circle in terrestrial ecosystem. However, modeling crown for individual tree is still challenging with the complex crown structure and changeable environmental conditions. This study was conducted to explore model in modeling the photosynthesis light response curve of the tree crown of young Larix principis-rupprechtii Mayr. Plantation. The rectangular hyperbolic model (RHM), non-rectangular hyperbolic model (NRHM), exponential model (EM) and modified rectangular hyperbolic model (MRHM) were used to model the photosynthetic light response curves. The fitting accuracy of these models was tested by comparing determinants coefficients (R2), mean square errors (MSE) and Akaike information criterion (AIC). The results showed that the mean value of R2 of MRHM (R2 = 0.9687) was the highest, whereas MSE value (MSE = 0.0748) and AIC value (AIC = -39.21) were the lowest. The order of fitting accuracy of the four models for Pn-PAR response curve was as follows: MRHM > EM > NRHM > RHM. In addition, the light saturation point (LSP) obtained by MRHM was slightly lower than the observed values, whereas the maximum net photosynthetic rates (Pmax) modeled by the four models were close to the measured values. Therefore, MRHM was superior to other three models in describing the photosynthetic response curve, the accurate values were that the quantum efficiency (α), maximum net photosynthetic rate (Pmax), light saturation point (LSP), light compensation point (LCP) and respiration rate (Rd) were 0.06, 6.06 μmol·m-2s-1, 802.68 μmol·m-2s-1, 10.76 μmol·m-2s-1 and 0.60 μmol·m-2s-1. Moreover, the photosynthetic response parameters values among different layers were also significant. Our findings have critical implications for parameter calibration of photosynthetic models and thus robust prediction of photosynthetic response in forests.

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Photosynthetic Characteristics of Four Wild Dendrobium Species in China

HortScience ◽

10.21273/hortsci.49.8.1023 ◽

2014 ◽

Vol 49 (8) ◽

pp. 1023-1027

Author(s):

Gang-Yi Wu ◽

Jun-Ai Hui ◽

Zai-Hua Wang ◽

Jie Li ◽

Qing-Sheng Ye

Keyword(s):

Glycolate Oxidase ◽

Photosynthetic Pathway ◽

Light Saturation ◽

Saturation Point ◽

Apparent Quantum Yield ◽

Bisphosphate Carboxylase ◽

Photosynthetic Physiology ◽

Light Saturation Point ◽

Second Peak ◽

Dendrobium Densiflorum

Photosynthetic physiology of Dendrobium nobile, Dendrobium pendulum, Dendrobium chrysotoxum, and Dendrobium densiflorum was studied. A bimodal diurnal variation of the net photosynthetic rate (Pn) was observed in the four Dendrobium species with the first peak [5.09 to 6.06 μmol (CO2) per m−2·s−1] ≈1100 hr and the second peak [3.83 to 4.58 μmol (CO2) per m−2·s−1] at 1500 hr. No CO2 fixation was observed at night. For all four Dendrobium species, the light compensation point (LCP) was 5 to 10 μmol·m−2·s−1, light saturation point (LSP) ranged from 800 to 1000 μmol·m−2·s−1, apparent quantum yield (AQY) was 0.02, and CO2 compensation points (CCP) and saturation point (CSP) were 60 to 85 μmol·mol−1 and 800 to 1000 μmol·mol−1, respectively. Carboxylation efficiency (CE) values ranged from 0.011 to 0.020. The optimum temperature for photosynthesis was between 26 and 30 °C. The measurement of Pn seasonal variation indicated that July to August had the higher Pn for Dendrobium species. Additionally, the chlorophyll a/b (Chl a/b) ratios of the leaves were 2.77 to 2.89. Measurement of key enzymes in the photosynthetic pathway indicated relatively high Ribulose-1,5-bisphosphate carboxylase (RuBPCase) and glycolate oxidase (GO) activities but very low phosphoenolpyruvate carboxylase (PEPCase) activities. It suggested that these four Dendrobium species are typical semishade C3 plants.

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The Photosynthetic Characteristics of Moso Bamboo (Phyllostachys pubescens) for Different Canopy Leaves

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.726-731.4274 ◽

2013 ◽

Vol 726-731 ◽

pp. 4274-4279

Author(s):

Yong Hui Cao ◽

Ben Zhi Zhou ◽

Xiao Ming Wang ◽

Gang Wang

Keyword(s):

Net Photosynthetic Rate ◽

Photosynthetic Rate ◽

Lower Layer ◽

Middle Layer ◽

B Value ◽

Phyllostachys Pubescens ◽

Light Saturation ◽

Saturation Point ◽

Low Light ◽

Light Saturation Point

The carbon sequestration ability of different ages of Phyllostachys pubescens was analyzed at three canopy layers with a LI-6400 portable photosynthesis system. Under different photosynthetically active radiation (PAR), the net photosynthetic rate (Pn) of upper and middle layers of 3-year old bamboo were significantly higher than that of lower layer. When the light was greater than 800 umol·m-2·s-1, the Pn of bamboo in middle layer was in the order of 3-year-old > 4-year- old >2-year-old >7-year-old bamboo. When the light was greater than 500 umol·m-2·s-1, Pn of lower layer was in the order of 3-year old > 4-year old >2-year old, while in the order of 3-year-old > 2-year -old >4-year-old bamboo during the low light range (PAR<200 umol·m-2·s-1).The chlorophyll a/b value, maximum net photosynthetic rate, light compensation point and light saturation point values change were reduced gradually with the decrease of canopy height.

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Assessing the spatial variability in peak season CO<sub>2</sub> exchange characteristics across the Arctic tundra using a light response curve parameterization

Biogeosciences ◽

10.5194/bg-11-4897-2014 ◽

2014 ◽

Vol 11 (17) ◽

pp. 4897-4912 ◽

Cited By ~ 15

Author(s):

H. N. Mbufong ◽

M. Lund ◽

M. Aurela ◽

T. R. Christensen ◽

W. Eugster ◽

...

Keyword(s):

Spatial Variability ◽

Response Curve ◽

Dark Respiration ◽

Light Response ◽

Arctic Tundra ◽

Co2 Exchange ◽

The Arctic ◽

Model Parameters ◽

Light Saturation ◽

Light Response Curve

Abstract. This paper aims to assess the spatial variability in the response of CO2 exchange to irradiance across the Arctic tundra during peak season using light response curve (LRC) parameters. This investigation allows us to better understand the future response of Arctic tundra under climatic change. Peak season data were collected during different years (between 1998 and 2010) using the micrometeorological eddy covariance technique from 12 circumpolar Arctic tundra sites, in the range of 64–74° N. The LRCs were generated for 14 days with peak net ecosystem exchange (NEE) using an NEE–irradiance model. Parameters from LRCs represent site-specific traits and characteristics describing the following: (a) NEE at light saturation (Fcsat), (b) dark respiration (Rd), (c) light use efficiency (α), (d) NEE when light is at 1000 μmol m−2 s−1 (Fc1000), (e) potential photosynthesis at light saturation (Psat) and (f) the light compensation point (LCP). Parameterization of LRCs was successful in predicting CO2 flux dynamics across the Arctic tundra. We did not find any trends in LRC parameters across the whole Arctic tundra but there were indications for temperature and latitudinal differences within sub-regions like Russia and Greenland. Together, leaf area index (LAI) and July temperature had a high explanatory power of the variance in assimilation parameters (Fcsat, Fc1000 and Psat, thus illustrating the potential for upscaling CO2 exchange for the whole Arctic tundra. Dark respiration was more variable and less correlated to environmental drivers than were assimilation parameters. This indicates the inherent need to include other parameters such as nutrient availability, substrate quantity and quality in flux monitoring activities.

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Photosynthesis of Birch Genotypes (Betula L.) Under Varied Irradiance and CO2 Concentration

HortScience ◽

10.21273/hortsci.43.2.314 ◽

2008 ◽

Vol 43 (2) ◽

pp. 314-319 ◽

Cited By ~ 1

Author(s):

Mengmeng Gu ◽

James A. Robbins ◽

Curt R. Rom ◽

Hyun-Sug Choi

Keyword(s):

Water Deficit ◽

Co2 Concentration ◽

Photosynthetic Photon Flux Density ◽

Photon Flux ◽

Photon Flux Density ◽

Water Deficit Stress ◽

Growth Enhancement ◽

Light Saturation ◽

Saturation Point ◽

Light Saturation Point

Net CO2 assimilation (A) of four birch genotypes (Betula nigra L. ‘Cully’, B. papyrifera Marsh., B. alleghaniensis Britton, and B. davurica Pall.) was studied under varied photosynthetic photon flux density (PPFD) and CO2 concentrations (CO2) as indicators to study their shade tolerance and potential for growth enhancement using CO2 enrichment. Effect of water-deficit stress on assimilation under varied PPFD and (CO2) was also investigated for B. papyrifera. The light saturation point at 350 ppm (CO2) for the four genotypes varied from 743 to 1576 μmol·m−2·s−1 photon, and the CO2 saturation point at 1300 μmol·m−2·s−1 photon varied from 767 to 1251 ppm. Light-saturated assimilation ranged from 10.4 μmol·m−2·s−1 in B. alleghaniensis to 13.1 μmol·m−2·s−1 in B. davurica. CO2-saturated A ranged from 18.8 μmol·m−2·s−1 in B. nigra ‘Cully’ to 33.3 μmol·m−2·s−1 in B. davurica. Water-deficit stress significantly reduced the light saturation point to 366 μmol photon m−2·s−1 but increased the CO2 saturation point in B. papyrifera. Carboxylation efficiency was reduced 46% and quantum efficiency was reduced 30% by water-deficit stress in B. papyrifera.

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Growth and Photosynthetic Capacity of Basil Grown for Indoor Gardening under Constant or Increasing Daily Light Integrals

HortTechnology ◽

10.21273/horttech04442-19 ◽

2019 ◽

Vol 29 (6) ◽

pp. 880-888 ◽

Cited By ~ 1

Author(s):

Elisa Solis-Toapanta ◽

Celina Gómez

Keyword(s):

Leaf Area ◽

Photosynthetic Capacity ◽

Dry Weight ◽

Growth And Yield ◽

Growth Responses ◽

Light Saturation ◽

Saturation Point ◽

Shoot Dry Weight ◽

Light Saturation Point ◽

Over Time

In the quest to identify minimum daily light integrals (DLIs) that can sustain indoor gardening, we evaluated DLIs less than the recommended ranges for commercial production of basil (Ocimum basilicum). Experiments were conducted for 8 weeks to evaluate the effect of providing a constant vs. an increasing DLI over time (DLIInc) on growth and photosynthetic capacity of green (‘Genovese Compact’) and purple (‘Red Rubin’) basil grown hydroponically under a constant ambient temperature of 21 °C. Plants were grown under a 14 h·d–1 photoperiod and were subjected to the following DLI treatments: 4 (DLI4), 6 (DLI6), 8 (DLI8), or 10 (DLI10) mol·m–2·d‒1 (80, 119, 159, and 197 µmol·m‒2·s‒1, respectively); DLIInc was used as a fifth treatment and was achieved by transitioning hydroponic systems systematically to treatments with greater DLIs every 2 weeks. In general, regardless of cultivar, leaf area, leaf number, and overall growth [shoot fresh weight (SFW) and shoot dry weight (SDW)] were similar for plants grown under DLIInc to DLI4 and DLI6 during weeks 2, 4, and 6. However, plants grown under DLIInc produced the same leaf area as those grown under DLI10 at week 8. Nonetheless, across weeks, growth was significantly less under DLIInc compared with DLI10, but similar to that produced by DLI8 at week 8. Photosynthetic responses were significant only at week 8, for which leaves of plants grown under DLI8, DLI10, and DLIInc had 15% to 25% greater maximum gross carbon dioxide (CO2) assimilation (Amax) than plants grown under DLI4. The light saturation point of photosynthesis was unaffected by DLI, but showed a general increasing trend with greater DLIs. Overall, our results suggest that providing a constantly high DLI results in greater growth and yield than increasing the DLI over time. In addition, we found that changes in Amax and the light saturation point are not good indicators of the capacity of whole plants to make use of the available light for photosynthesis and growth. Instead, morphological and developmental traits regulated by DLI during the initial stages of production are most likely responsible for the growth responses measured in our study.

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Effects of light stress and light recovery on two maize (Zea mays L.) cultivars

Bangladesh Journal of Botany ◽

10.3329/bjb.v48i3.47912 ◽

2019 ◽

Vol 48 (3) ◽

pp. 513-520

Author(s):

Hongyu Zhang ◽

Ping Tian ◽

Nan Mel ◽

Pengxiang Sui ◽

Wenke Zhang ◽

...

Keyword(s):

Chlorophyll Fluorescence ◽

Quantum Efficiency ◽

Light Stress ◽

Light Saturation ◽

Saturation Point ◽

Chlorophyll Fluorescence Parameters ◽

Fluorescence Parameters ◽

Apparent Quantum Efficiency ◽

Weak Light ◽

Light Saturation Point

The responses of a density-tolerant (ZD909) and a density-intolerant (DY405) maize cultivar to weak light stress and light recovery were compared. Photosynthetic characteristics and chlorophyll fluorescence parameters were analyzed under three light treatments: natural light (control), 44% shading and 66% shading. The light-saturation point and light-compensation point of both the maize cultivars decreased, whereas the apparent quantum efficiency increased during the shade period and the decreasing degree of light-saturation point and light-compensation point and the increasing degree of apparent quantum efficiency of the ZD909 were both higher than those of DY405. The weak light stress in the spike stage had a greater influence on the photosynthetic characteristics and chlorophyll fluorescence parameters of DY405, which indicated DY405 was less able to adapt to a weak light environment compared with ZD909.

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Control of the Light Saturation Point for Photosynthesis in Tomato

Physiologia Plantarum ◽

10.1111/j.1399-3054.1974.tb03682.x ◽

1974 ◽

Vol 31 (3) ◽

pp. 153-158 ◽

Cited By ~ 4

Author(s):

C. D. MILES

Keyword(s):

Light Saturation ◽

Saturation Point ◽

Light Saturation Point

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Assessing the spatial variability in peak season CO<sub>2</sub> exchange characteristics across the Arctic tundra using a light response curve parameterization

Biogeosciences Discussions ◽

10.5194/bgd-11-6419-2014 ◽

2014 ◽

Vol 11 (5) ◽

pp. 6419-6460 ◽

Cited By ~ 2

Author(s):

H. N. Mbufong ◽

M. Lund ◽

M. Aurela ◽

T. R. Christensen ◽

W. Eugster ◽

...

Keyword(s):

Spatial Variability ◽

Response Curve ◽

Dark Respiration ◽

Light Response ◽

Arctic Tundra ◽

Co2 Exchange ◽

The Arctic ◽

Model Parameters ◽

Light Saturation ◽

Light Response Curve

Abstract. This paper aims to assess the functional and spatial variability in the response of CO2 exchange to irradiance across the Arctic tundra during peak season using light response curve (LRC) parameters. This investigation allows us to better understand the future response of Arctic tundra under climatic change. Data was collected using the micrometeorological eddy covariance technique from 12 circumpolar Arctic tundra sites, in the range of 64–74° N. The LRCs were generated for 14 days with peak net ecosystem exchange (NEE) using an NEE -irradiance model. Parameters from LRCs represent site specific traits and characteristics describing: (a) NEE at light saturation (Fcsat), (b) dark respiration (Rd), (c) light use efficiency (α), (d) NEE when light is at 1000 μmol m−2 s−1 (Fc1000), (e) potential photosynthesis at light saturation (Psat) and (f) the light compensation point (LCP). Parameterization of LRCs was successful in predicting CO2 flux dynamics across the Arctic tundra. Yet we did not find any trends in LRC parameters across the whole Arctic tundra but there were indications for temperature and latitudinal differences within sub-regions like Russia and Greenland. Together, LAI and July temperature had a high explanatory power of the variance in assimilation parameters (Fcsat, Fc1000 and Psat), thus illustrating the potential for upscaling CO2 exchange for the whole Arctic tundra. Dark respiration was more variable and less correlated to environmental drivers than was assimilation parameters. Thus, indicating the inherent need to include other parameters such as nutrient availability, substrate quantity and quality in flux monitoring activities.

Download Full-text