Nonlinear Relationship Between the Yield of Solar-Induced Chlorophyll Fluorescence and Photosynthetic Efficiency in Senescent Crops

It has been demonstrated that solar-induced chlorophyll fluorescence (SIF) is linearly related to the primary production of photosynthesis (GPP) in various ecosystems. However, it is unknown whether such linear relationships have been established in senescent crops. SIF and GPP can be expressed as the products of absorbed photosynthetically active radiation (APAR) with the SIF yield and photosystem II (PSII) operating efficiency, respectively. Thus, the relationship between SIF and GPP can be represented by the relationship between the SIF yield and PSII operating efficiency when the APAR has the same value. Therefore, we analyzed the relationship between the SIF yield and the PSII operating efficiency to address the abovementioned question. Here, diurnal measurements of the canopy SIF (760 nm, F760) of soybean and sweet potato were manually measured and used to calculate the SIF yield. The PSII operating efficiency was calculated from measurements of the chlorophyll fluorescence at the leaf level using the FluorImager chlorophyll fluorescence imaging system. Meanwhile, field measurements of the gas exchange and other physiological parameters were also performed using commercial-grade devices. The results showed that the SIF yield was not linearly related to the PSII operating efficiency at the diurnal scale, reflecting the nonlinear relationship between SIF and GPP. This nonlinear relationship mainly resulted from the heterogeneity and diurnal dynamics of the PSII operating efficiency and from the intrinsic diurnal changes in the maximum efficiency of the PSII photochemistry and the proportion of opened PSII centers. Intensifying respiration was another factor that complicated the response of photosynthesis to the variation in environmental conditions and negatively impacted the relationship between the SIF yield and the PSII operating efficiency. The nonlinear relationship between the SIF yield and PSII efficiency might yield errors in the estimation of GPP using the SIF measurements of senescent crops.

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The Relationship Between the Maximum Efficiency and the Flow of Centrifugal Pumps in Parallel Operation

Journal of Pressure Vessel Technology ◽

10.1115/1.4001141 ◽

2010 ◽

Vol 132 (3) ◽

Cited By ~ 2

Author(s):

Yi Wen ◽

Xiaochu Zhang ◽

Pu Wang

Keyword(s):

Centrifugal Pump ◽

Maximum Efficiency ◽

Operating Efficiency ◽

Parallel Operation ◽

Flow Ratio ◽

Centrifugal Pumps ◽

The Relationship

The maximum operating efficiency of a centrifugal pump is different when it is parallel operated with different pumps. To study the reduction in the maximum operating efficiency of pumps in parallel operation compared with their rated efficiency, 28 pairs of pumps with the same rated head and different rated flows were tested orthogonally in parallel operation. A determination of the pumps operating flow and head was done to calculate the maximum operating efficiency in different combinations. The results showed that the maximum operating efficiency of a pump in parallel operation was higher than 85% of rated efficiency when the flow ratio of two pumps was within 1.6. When the flow ratio was increased to 2.0, the maximum operating efficiency of the pump will sharply decline to 70% of rated efficiency or less. Therefore, the operating efficiency a pump can keep is 70% or more under the condition that the flow ratio between the pumps is less than 2.

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Chlorophyll fluorescence parameters allow the rapid detection and differentiation of plant responses in three different wheat pathosystems

Functional Plant Biology ◽

10.1071/fp15280 ◽

2016 ◽

Vol 43 (4) ◽

pp. 356 ◽

Cited By ~ 13

Author(s):

Olubukola O. Ajigboye ◽

Louise Bousquet ◽

Erik H. Murchie ◽

Rumiana V. Ray

Keyword(s):

Chlorophyll Fluorescence ◽

Powdery Mildew ◽

Fusarium Culmorum ◽

Maximum Efficiency ◽

Plant Responses ◽

Head Blight ◽

Chlorophyll Fluorescence Parameters ◽

Psii Photochemistry ◽

Oculimacula Yallundae ◽

Pathogen Dna

The present study was undertaken to identify chlorophyll fluorescence (CF) parameters that can quantify changes in PSII associated with plant responses in three different wheat pathosystems of foliar, stem-base and ear diseases. The pathosystems included powdery mildew caused by Blumeria graminis, eyespot caused by Oculimacula yallundae or Oculimacula acuformis and Fusarium head blight (FHB) caused by Fusarium culmorum, F. avenaceum or F. langsethiae. Fast CF transients (OJIP) were analysed with the JIP-test to determine changes in PSII photochemistry. Measurements on asymptomatic leaves showed that electron transport related parameters (ETo/RC, ψo and ϕEo) were important to identify varietal differences in resistance to powdery mildew during early stages of infection. The same parameters also allowed differentiation between F. langsethiae and other Fusarium spp. Where infections were caused by the necrotrophic pathogens, Oculimacula spp., F. culmorum or F. avenaceum, changes related to maximum efficiency of PSII photochemistry (Fvʹ/Fmʹ) as well as flux of dissipated (DIo/RC), trapped (TRo/RC), or absorbed (ABS/RC) energy per active reaction centers were significant in detecting biotic stress and the effectiveness of fungicide treatment for disease control. Our results demonstrated that Fvʹ/Fmʹ correlated significantly with visual disease and pathogen DNA of different wheat pathosystems. OJIP was shown as a sensitive technique that can be explored as diagnostic tool in future crop disease management and varietal breeding programs.

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Tissue culture as a source of replicates in non-model plants: variation in cold tolerance inArabidopsis lyratassp.petraea

10.1101/043695 ◽

2016 ◽

Author(s):

Tanaka Kenta ◽

Jessica Edwards ◽

Roger K Butlin ◽

Terry Burke ◽

Paul Quick ◽

...

Keyword(s):

Tissue Culture ◽

Chlorophyll Fluorescence ◽

Somaclonal Variation ◽

Cold Tolerance ◽

Cold Treatment ◽

Maximum Efficiency ◽

Operating Efficiency ◽

Environment Interaction ◽

Fluorescence Measurements ◽

Genotype Environment Interaction

Whilst genotype–environment interaction is increasingly receiving attention by ecologists and evolutionary biologists, such studies need genetically homogeneous replicates—a challenging hurdle in outcrossing plants. This could potentially be overcome by using tissue culture techniques. However, plants regenerated from tissue culture may show aberrant phenotypes and “somaclonal” variation. Here we examined the effects of tissue culturing by clonal growth on the response to cold treatment in the photosynthetic efficiency (chlorophyll fluorescence measurements for Fv/Fm, Fv′/Fm′ and ФPSII, representing maximum efficiency of photosynthesis for dark- and light-adapted leaves, and the actual electron transport operating efficiency, respectively), compared to half-sibling seedlings from three different families ofArabidopsis lyratassp.petraea. Somaclonal variation was limited and we could successfully detect within-family variation in change in chlorophyll fluorescence by cold shock with the help of tissue-culture derived replicates. Icelandic and Norwegian families exhibited higher chlorophyll fluorescence, suggesting higher cold tolerance, than a Swedish family. Although the main effect of tissue culture on Fv/Fm, Fv′/Fm′ and ФPSII was small, there were significant interactions between tissue culture and family, suggesting that the effect of tissue culture is genotype-specific. Tissue-cultured plantlets were less affected by cold treatment than seedlings, but to a different extent in each family. These interactive effects, however, were comparable to, or much smaller than the single effect of family. These results suggest that tissue culture is a useful method for obtaining genetically homogenous replicates for studying genotype‐environment interaction related to adaptively relevant phenotypes, such as cold tolerance, in non-model outcrossing plants.

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Exploring the scattering and reabsorption of chlorophyll fluorescence: implications for remote sensing of photosynthesis

10.5194/egusphere-egu2020-18194 ◽

2020 ◽

Author(s):

Karolina Sakowska ◽

Maria Pilar Cendrero-Mateo* ◽

Christiaan van der Tol ◽

Marco Celesti ◽

Giorgio Alberti ◽

...

Keyword(s):

Chlorophyll Fluorescence ◽

Heat Dissipation ◽

Structural Parameters ◽

Vegetation Indices ◽

Field Measurements ◽

Photosynthetic Performance ◽

Photochemical Quenching ◽

Spectral Vegetation Indices ◽

Leaf Level ◽

Scope Model

In recent years, technological progress in high-resolution field spectrometers have enabled the use of alternative tracer for constraining ecosystem-scale photosynthesis, i.e. sun-induced fluorescence (SIF). The principle underlying the use of SIF as a proxy of gross primary productivity (GPP) is based on the fact that the light energy absorbed by chlorophyll molecules can proceed into three different pathways: photochemistry, heat dissipation, and chlorophyll fluorescence. Since these processes directly compete for the same excitation energy, measurements of SIF and non-photochemical quenching (NPQ) are expected to provide information on photosynthetic performance.However, SIF signal measured at the leaf level or beyond is affected by several processes, including wavelength dependent scattering and reabsorption, which may need to be considered when linking SIF data and photosynthetic CO2 assimilation.To address this question, we conducted a multi-scale and multi-technique study that considered measurements of photosynthetic (GPP), optical (SIF, reflectance - R and transmittance - T), physiological (NPQ) and biophysical (the amount of absorbed photosynthetically active radiation - APAR) parameters of two soybean varieties: the MinnGold mutant, characterized by significantly reduced chlorophyll content (Chl), and the wild type, non-Chl deficient Eiko. We further used the &#8220;Soil-Canopy Observation Photosynthesis and Energy fluxes&#8221; (SCOPE) model to investigate the reabsorption and scattering of SIF. The measured leaf R, T and SIF and top-of-the-canopy R were used to retrieve biochemical and structural parameters of both varieties by inversion of the SCOPE model, while its forward mode was used to determine and correct for the scattering and reabsorption of SIF at both leaf and canopy level.Our study revealed that despite the large difference in Chl content (the ratio of Chl between MinnGold and Eiko was nearly 1:5), similar leaf and canopy photosynthesis rates were maintained in the Chl&#8208;deficient mutant. This phenomenon was captured neither by traditional spectral vegetation indices related to canopy greenness, nor by SIF measured in-situ. However, the modelling simulations revealed that when correcting for leaf and canopy scattering and reabsorption processes both varieties presented similar SIF yield (SIF/APAR). Furthermore, field measurements showed that APAR and NPQ in MinnGold were lower than in Eiko. This together explains the similar measured GPP and simulated SIF yield between the two varieties, and indicates that interpretation and application of SIF as a GPP tracer requires understanding and quantification of all these processes.

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Diurnal and Seasonal Variations in Chlorophyll Fluorescence Associated with Photosynthesis at Leaf and Canopy Scales

Remote Sensing ◽

10.3390/rs11050488 ◽

2019 ◽

Vol 11 (5) ◽

pp. 488 ◽

Cited By ~ 17

Author(s):

Petya Campbell ◽

Karl Huemmrich ◽

Elizabeth Middleton ◽

Lauren Ward ◽

Tommaso Julitta ◽

...

Keyword(s):

Chlorophyll Fluorescence ◽

Zea Mays L ◽

Electron Transport Rate ◽

Light Conditions ◽

Linear Relationships ◽

Leaf Level ◽

Seasonal And Diurnal Variation ◽

Use Efficiency ◽

Natural Dynamics ◽

The Relationship

There is a critical need for sensitive remote sensing approaches to monitor the parameters governing photosynthesis, at the temporal scales relevant to their natural dynamics. The photochemical reflectance index (PRI) and chlorophyll fluorescence (F) offer a strong potential for monitoring photosynthesis at local, regional, and global scales, however the relationships between photosynthesis and solar induced F (SIF) on diurnal and seasonal scales are not fully understood. This study examines how the fine spatial and temporal scale SIF observations relate to leaf level chlorophyll fluorescence metrics (i.e., PSII yield, YII and electron transport rate, ETR), canopy gross primary productivity (GPP), and PRI. The results contribute to enhancing the understanding of how SIF can be used to monitor canopy photosynthesis. This effort captured the seasonal and diurnal variation in GPP, reflectance, F, and SIF in the O2A (SIFA) and O2B (SIFB) atmospheric bands for corn (Zea mays L.) at a study site in Greenbelt, MD. Positive linear relationships of SIF to canopy GPP and to leaf ETR were documented, corroborating published reports. Our findings demonstrate that canopy SIF metrics are able to capture the dynamics in photosynthesis at both leaf and canopy levels, and show that the relationship between GPP and SIF metrics differs depending on the light conditions (i.e., above or below saturation level for photosynthesis). The sum of SIFA and SIFB (SIFA+B), as well as the SIFA+B yield, captured the dynamics in GPP and light use efficiency, suggesting the importance of including SIFB in monitoring photosynthetic function. Further efforts are required to determine if these findings will scale successfully to airborne and satellite levels, and to document the effects of data uncertainties on the scaling.

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The Relationship between Chlorophyll Fluorescence Parameter (Fv/Fm) and Frequency Component of Plant Bioelectric Potential in Spraying Chemical Herbicides

IEEJ Transactions on Sensors and Micromachines ◽

10.1541/ieejsmas.132.154 ◽

2012 ◽

Vol 132 (6) ◽

pp. 154-158

Author(s):

Shin-ichi Shibata ◽

Fumitake Satou ◽

Haruhiko Kimura ◽

Takashi Oyabu

Keyword(s):

Chlorophyll Fluorescence ◽

Frequency Component ◽

Bioelectric Potential ◽

Chlorophyll Fluorescence Parameter ◽

Fluorescence Parameter ◽

The Relationship

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The spatial heterogeneity of the relationship between gross primary production and sun-induced chlorophyll fluorescence regulated by climate conditions during 2007-2018

Global Ecology and Conservation ◽

10.1016/j.gecco.2021.e01721 ◽

2021 ◽

pp. e01721

Author(s):

Yonglin Wang ◽

Lei Zhou ◽

Jie Zhuang ◽

Leigang Sun ◽

Yonggang Chi

Keyword(s):

Chlorophyll Fluorescence ◽

Primary Production ◽

Spatial Heterogeneity ◽

Gross Primary Production ◽

Climate Conditions ◽

The Relationship

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Fecundity Comparisons for Various Stocks of Lake Whitefish, Coregonus clupeaformis

Journal of the Fisheries Research Board of Canada ◽

10.1139/f75-048 ◽

1975 ◽

Vol 32 (3) ◽

pp. 404-407 ◽

Cited By ~ 7

Author(s):

M. C. Healey ◽

C. W. Nicol

Keyword(s):

Northwest Territories ◽

Lake Erie ◽

Fork Length ◽

Nonlinear Relationship ◽

Coregonus Clupeaformis ◽

Lake Whitefish ◽

Limited Data ◽

Relative Fecundity ◽

Great Slave Lake ◽

The Relationship

We found no significant differences in slope or intercept for the regression of loge fecundity on loge fork length among samples of whitefish from four lakes near Yellowknife in the Northwest Territories. The equation describing the relationship between fecundity and fork length for these populations was:[Formula: see text]Five other populations for which length–fecundity relationships could be calculated had length exponents ranging from 3.20 to 4.38, suggesting a nonlinear relationship between weight and fecundity. Six of the nine populations as well as four others for which limited data were available all had similar relative fecundities. Fish from Buck Lake in Alberta and from Lake Erie had high relative fecundities while fish from Great Slave Lake had low relative fecundity.

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