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

HortScience ◽  
2008 ◽  
Vol 43 (2) ◽  
pp. 314-319 ◽  
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.

scholarly journals Interaction of Light Intensity and CO2 Concentration Alters Biomass Partitioning in Chrysanthemum

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Maral Hosseinzadeh ◽  
Sasan Aliniaeifard ◽  
Aida Shomali ◽  
Fardad Didaran
Keyword(s):  
Light Intensity ◽  
Growth Management ◽  
Growth Yield ◽  
Dry Weight ◽  
Co2 Concentration ◽  
Photosynthetic Photon Flux Density ◽  
Biomass Partitioning ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Vegetative Organs

Abstract Biomass partitioning is one of the pivotal determinants of crop growth management, which is influenced by environmental cues. Light and CO2 are the main drivers of photosynthesis and biomass production in plants. In this study, the effects of CO2 levels: ambient 400 ppm (a[CO2]) and elevated to 1,000 ppm (e[CO2]) and different light intensities (75, 150, 300, 600 μmol·m−2·s−1 photosynthetic photon flux density – PPFD) were studied on the growth, yield, and biomass partitioning in chrysanthemum plants. The plants grown at higher light intensity had a higher dry weight (DW) of both the vegetative and floral organs. e[CO2] diminished the stimulating effect of more intensive light on the DW of vegetative organs, although it positively influenced inflorescence DW. The flowering time in plants grown at e[CO2] and light intensity of 600 μmol·m−2·s−1 occurred earlier than that of plants grown at a[CO2]. An increase in light intensity induced the allocation of biomass to inflorescence and e[CO2] enhanced the increasing effect of light on the partitioning of biomass toward the inflorescence. In both CO2 concentrations, the highest specific leaf area (SLA) was detected under the lowest light intensity, especially in plants grown at e[CO2]. In conclusion, elevated light intensity and CO2 direct the biomass toward inflorescence in chrysanthemum plants.

scholarly journals Photosynthetic Performance of Glyphosate Resistant and Glyphosate Susceptible Hairy Fleabane under Light Intensity

2018 ◽  
Vol 35 (0) ◽  
Author(s):  
D.R.O. SILVA ◽  
L. VARGAS ◽  
D. AGOSTINETTO ◽  
F.M. SANTOS
Keyword(s):  
Transpiration Rate ◽  
Weed Management ◽  
Co2 Concentration ◽  
Photosynthetic Photon Flux Density ◽  
Photosynthetic Performance ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Photosynthetic Parameters ◽  
Management History ◽  
Hairy Fleabane

ABSTRACT: Herbicide resistance can confer lower competitive abilities; however scarse information is available about the photosynthetic performance between glyphosate-resistant and -susceptible hairy fleabane biotypes coming from areas with similar weed management history. Thus, the goal was to evaluate the photosynthetic performance under different light intensities between glyphosate-resistant and -susceptible hairy fleabane biotypes, from RR soybean fields with a similar weed management history. The tested factors were glyphosate resistant and susceptible biotypes and 12 levels of photosynthetic photon flux density. Plants were cultivated in plastic cups, and at the stage of 10-12 leaves they were subjected to treatments with artificial lighting systems. The net photosynthetic rate, stomatal conductance, substomatal CO2 concentration, transpiration rate, instantaneous water use efficiency, light compensation point and quantum yield were evaluated. In all the evaluated photosynthetic parameters, biotype R showed superior characteristics compared to susceptible biotypes, with the exception of the transpiration rate, where there were no differences. The differences between biotypes may not be associated to glyphosate resistance or susceptibility, but to the evolutionary characteristics of the biotypes.

Effects of soyabean leaflet inclination on some factors related to photosynthesis

2002 ◽  
Vol 138 (4) ◽  
pp. 367-373 ◽  
Author(s):  
T. IKEDA ◽  
R. MATSUDA
Keyword(s):  
Carbon Dioxide Concentration ◽  
Plant Production ◽  
Physiological Adaptation ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Light Saturation ◽  
Saturation Point ◽  
Group Vi ◽  
Solar Tracking ◽  
Net Assimilation

Leaflet movement in soyabean (Glycine max (L.) Merr.) is considered to be an important physiological adaptation for intercepting sunlight for photosynthesis. Solar tracking may serve to increase plant production by maximizing light interception. The objective of this study was to determine the response of A (leaflet net assimilation rate), τ (stomatal conductance) and Ci (internal leaf carbon dioxide concentration) when penultimate fully expanded leaflet angles were changed. Soyabean (cv. Enrei, Maturity group VI) was planted at Niigata University, Japan, at two densities (25 and 16 plants/m2) in mid-May of 1992 and 1993. PFD (photon flux density), A, τ, and Ci were measured with a portable leaf photosynthesis instrument. The more towards vertical the leaflets were moved, the lower the PFD and A were. A measured at R5 showed no light saturation, but did show this at V13 and R3. While A measured at 09.00 h showed no saturation point, there was saturation at 12.00 h and 15.00 h at or less than 1500 μmol/m2/s. At R3 a high correlation (r = 0.89, P < 0.01) was found between PFD and A for naturally oriented leaflets, but not for horizontal ones. These results suggest that leaflet movement is an adaptation to optimize A.

Responses of Soybean (Glycine max) and Three C4Grass Weeds to CO2Enrichment During Drought

Weed Science ◽  
1986 ◽  
Vol 34 (2) ◽  
pp. 203-210 ◽  
Author(s):  
David T. Patterson
Keyword(s):  
Glycine Max ◽  
Water Stress ◽  
Leaf Area ◽  
Dry Weight ◽  
Growth Stimulation ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Growth Enhancement ◽  
Total Dry Weight

In controlled-environment chambers at 29/33 C day/night and 1000 μE·m-2·s-1photosynthetic photon flux density (PPFD), increasing the CO2concentration from 350 to 675 ppm (v/v) did not affect leaf area or total dry weight of well-watered plants of barnyardgrass [Echinochloa crus-galli(L.) Beauv. # ECHCG], goosegrass [Eleusine indica(L.) Gaertn. # ELEIN], or southern crabgrass [Digitaria ciliaris(Retz.) Koel. # DIGSP] after 30 days. However, the whole plant transpiration rate per unit leaf area decreased, and the water use efficiency increased, in response to CO2enrichment. In a subsequent experiment, with water availability limited by an imposed drought, CO2enrichment reduced the effects of water stress and significantly increased leaf area and total dry weight of the three C4grasses and soybean [Glycine max(L.) Merr. ‘Ransom’]. Growth enhancement in response to CO2enrichment was greater in soybean than in the C4grasses. By improving their water economy, CO2enrichment can increase the growth of both C3and C4plants under water stress. However, growth stimulation can be expected to be greater in C3plants.

scholarly journals Gas exchanges in peach palms as a function of the spad chlorophyll meter readings

2011 ◽  
Vol 33 (spe1) ◽  
pp. 267-274 ◽  
Author(s):  
Maria Luiza Sant'anna Tucci ◽  
Valéria Aparecida Modolo ◽  
Norma de Magalhães Erismann ◽  
Eduardo Caruso Machado
Keyword(s):  
Intercellular Co2 Concentration ◽  
Co2 Concentration ◽  
Co2 Assimilation ◽  
Photosynthetic Photon Flux Density ◽  
Linear Increase ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Gas Exchanges ◽  
Complementary Method ◽  
Spad Readings

The close relationship between the chlorophyll-meters readings and the total chlorophyll and nitrogen contents in leaves, has allowed their evaluation both in annual and perennial species. Besides, some physiological events such as the CO2 assimilation have also been estimated by chlorophyll meters. This work was carried out aiming to evaluate the gas exchanges of peach palms as a function of the chlorophyll SPAD-Meter readings. Three year-old peach palms from Yurimaguas, Peru were studied in Ubatuba, SP, Brazil, spaced 2 x 1 m in area under a natural gradient of organic matter which allowed four plots to be considered, according to the peach palms leaves colors, from light yellow to dark green. The SPAD readings and the stomatal frequency of leaflets were evaluated. The photosynthetic photon flux density (PPFD, μmol m-2 s-1), the leaf temperature (Tleaf, ºC), the CO2 assimilation (A, μmol m-2 s-1), the stomatal conductance (g s, mol m-2 s-1), the transpiration (E, mmol m-2 s-1) and the intercellular CO2 concentration (Ci, μmol mol-1) were evaluated with a portable infrared gas analyzer (LCA-4, ADC BioScientific Ltd., Great Amwell, U.K.). A linear increase in the CO2 assimilation as a function of the SPAD readings (y = -0.34 + 0.19x, R² = 0.99), indicates that they can be a rapid and cheap complementary method to evaluate in peach palms some important physiological events, such as CO2 assimilation.

Photosynthetic Characteristics of Sun Versus Shade Plants of Encelia farinosa as Affected by Photosynthetic Photon Flux Density, Intercellular CO2 Concentration, Leaf Water Potential, and Leaf Temperature

1995 ◽  
Vol 22 (5) ◽  
pp. 833 ◽  
Author(s):  
Hehui Zhang ◽  
MR Sharifi ◽  
PS Nobel
Keyword(s):  
Electron Transport ◽  
Intercellular Co2 Concentration ◽  
Co2 Concentration ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Photosynthetic Photon Flux ◽  
Sun And Shade ◽  
Shade Plants ◽  
Intercellular Co2

Limitations to photosynthesis were examined for Encelia farinosa Toney et A.Gray, a common C3 sub-shrub in arid regions of south-westem United States, for plants grown in full sunlight and those shaded to 40% of full sunlight. The initial slopes of CO2 assimilation (A) versus intercellular CO2 concentration curves were similar for sun and shade plants at low photosynthetic photon flux density (PPFD) but higher for sun plants as the PPFD increased, indicating a greater limitation by carboxylation capacity in shade plants. Sun plants had higher electron transport rates but a lower ratio of electron transport capacity to carboxylation capacity (Vmax); the ratio was inversely proportional to mesophyll conductance for both sun and shade plants. Dark respiration decreased with decreasing leaf water potential (Ψ1) in sun plants but remained unchanged in shade plants; day respiration was little affected by PPFD for both sun and shade plants. Stomatal conductance (gs) was similar for sun and shade plants under high soil-moisture conditions but higher in sun plants as Ψ1 decreased; for all data considered together, changes in the leaf-air vapour pressure difference accounted for 71% of the variation in gs. The lower A for shade plants of E. farinosa apparently resulted from a lower Vmax, as well as a lower gs when plants were under water stress.

scholarly journals Light-Mediated Reduction in Photosynthesis in Closed Greenhouses Can Be Compensated for by CO2 Enrichment in Tomato Production

Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2808
Author(s):  
Dennis Dannehl ◽  
Hans-Peter Kläring ◽  
Uwe Schmidt
Keyword(s):  
Co2 Enrichment ◽  
Net Photosynthesis ◽  
Co2 Concentration ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Technical Equipment ◽  
Tomato Production ◽  
Gas Exchange System ◽  
Mediated Reduction

Concepts of semi-closed greenhouses can be used to save energy, whereas their technical equipment often causes a decrease in the light received by the plants. Nevertheless, higher yields are achieved, which are presumably triggered by a higher CO2 concentration in the greenhouse and associated higher photosynthesis because of the technical cooling and the longer period of closed ventilation. Therefore, we examined the effects of photosynthetic photon flux density (PPFD) and CO2 concentration on plant photosynthesis and transpiration in tomato using a multiple cuvette gas exchange system. In a growth chamber experiment, we demonstrated that a light-mediated reduction in photosynthesis can be compensated or even overcompensated for by rising CO2 concentration. Increasing the CO2 concentration from 400 to 1000 µmol mol−1 within the PPFD range from 303 to 653 µmol m−2 s−1 resulted in an increase in net photosynthesis of 51%, a decrease in transpiration of 5 to 8%, and an increase in photosynthetic water use efficiency of 60%. Estimations showed that light reductions of 10% can be compensated for via increasing the CO2 concentration by about 100 µmol mol−1 and overcompensated for by about 40% if CO2 concentration is kept at 1000 instead of 400 µmol mol−1.

scholarly journals LED Illumination Spectrum Manipulation for Increasing the Yield of Sweet Basil (Ocimum basilicum L.)

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 344
Author(s):  
Md Momtazur Rahman ◽  
Mikhail Vasiliev ◽  
Kamal Alameh
Keyword(s):  
Growth Rate ◽  
Fold Increase ◽  
Photosynthetic Photon Flux Density ◽  
Ocimum Basilicum ◽  
Photon Flux ◽  
Photon Flux Density ◽  
White Led ◽  
Experimental Conditions ◽  
Sweet Basil ◽  
Optimal Illumination

Manipulation of the LED illumination spectrum can enhance plant growth rate and development in grow tents. We report on the identification of the illumination spectrum required to significantly enhance the growth rate of sweet basil (Ocimum basilicum L.) plants in grow tent environments by controlling the LED wavebands illuminating the plants. Since the optimal illumination spectrum depends on the plant type, this work focuses on identifying the illumination spectrum that achieves significant basil biomass improvement compared to improvements reported in prior studies. To be able to optimize the illumination spectrum, several steps must be achieved, namely, understanding plant biology, conducting several trial-and-error experiments, iteratively refining experimental conditions, and undertaking accurate statistical analyses. In this study, basil plants are grown in three grow tents with three LED illumination treatments, namely, only white LED illumination (denoted W*), the combination of red (R) and blue (B) LED illumination (denoted BR*) (relative red (R) and blue (B) intensities are 84% and 16%, respectively) and a combination of red (R), blue (B) and far-red (F) LED illumination (denoted BRF*) (relative red (R), blue (B) and far-red (F) intensities are 79%, 11%, and 10%, respectively). The photosynthetic photon flux density (PPFD) was set at 155 µmol m−2 s−1 for all illumination treatments, and the photoperiod was 20 h per day. Experimental results show that a combination of blue (B), red (R), and far-red (F) LED illumination leads to a one-fold increase in the yield of a sweet basil plant in comparison with only white LED illumination (W*). On the other hand, the use of blue (B) and red (R) LED illumination results in a half-fold increase in plant yield. Understanding the effects of LED illumination spectrum on the growth of plant sweet basil plants through basic horticulture research enables farmers to significantly improve their production yield, thus food security and profitability.

scholarly journals Plant buffering against the high-light stress-induced accumulation of CsGA2ox8 transcripts via alternative splicing to finely tune gibberellin levels and maintain hypocotyl elongation

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Bin Liu ◽  
Shuo Zhao ◽  
Pengli Li ◽  
Yilu Yin ◽  
Qingliang Niu ◽  
...  
Keyword(s):  
Alternative Splicing ◽  
Light Intensity ◽  
Intron Retention ◽  
Light Stress ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Rna Seq ◽  
Multiple Transcripts ◽  
Novel Transcript

AbstractIn plants, alternative splicing (AS) is markedly induced in response to environmental stresses, but it is unclear why plants generate multiple transcripts under stress conditions. In this study, RNA-seq was performed to identify AS events in cucumber seedlings grown under different light intensities. We identified a novel transcript of the gibberellin (GA)-deactivating enzyme Gibberellin 2-beta-dioxygenase 8 (CsGA2ox8). Compared with canonical CsGA2ox8.1, the CsGA2ox8.2 isoform presented intron retention between the second and third exons. Functional analysis proved that the transcript of CsGA2ox8.1 but not CsGA2ox8.2 played a role in the deactivation of bioactive GAs. Moreover, expression analysis demonstrated that both transcripts were upregulated by increased light intensity, but the expression level of CsGA2ox8.1 increased slowly when the light intensity was >400 µmol·m−2·s−1 PPFD (photosynthetic photon flux density), while the CsGA2ox8.2 transcript levels increased rapidly when the light intensity was >200 µmol·m−2·s−1 PPFD. Our findings provide evidence that plants might finely tune their GA levels by buffering against the normal transcripts of CsGA2ox8 through AS.

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