High-throughput chlorophyll fluorescence screening of Setaria viridis for mutants with altered CO2 compensation points

2018 ◽  
Vol 45 (10) ◽  
pp. 1017 ◽  
Author(s):  
Robert A. Coe ◽  
Jolly Chatterjee ◽  
Kelvin Acebron ◽  
Jacqueline Dionora ◽  
Reychelle Mogul ◽  
...  
Keyword(s):  
High Throughput ◽  
Photosynthetic Efficiency ◽  
Co2 Concentration ◽  
Compensation Point ◽  
Wild Type Plant ◽  
Setaria Viridis ◽  
Photosynthetic Pathway ◽  
Ambient Conditions ◽  
Co2 Compensation Point ◽  
A Value

To assist with efforts to engineer a C4 photosynthetic pathway into rice, forward-genetic approaches are being used to identify the genes modulating key C4 traits. Currently, a major challenge is how to screen for a variety of different traits in a high-throughput manner. Here we describe a method for identifying C4 mutant plants with increased CO2 compensation points. This is used as a signature for decreased photosynthetic efficiency associated with a loss of C4 function. By exposing plants to a CO2 concentration close to the CO2 compensation point of a wild-type plant, individuals can be identified from measurements of chlorophyll a fluorescence. We use this method to screen a mutant population of the C4 monocot Setaria viridis (L.)P.Beauv. generated using N-nitroso-N-methylurea (NMU). Mutants were identified at a frequency of 1 per 157 lines screened. Forty-six candidate lines were identified and one line with a heritable homozygous phenotype selected for further characterisation. The CO2 compensation point of this mutant was increased to a value similar to that of C3 rice. Photosynthesis and growth was significantly reduced under ambient conditions. These data indicate that the screen was capable of identifying mutants with decreased photosynthetic efficiency. Characterisation and next-generation sequencing of all the mutants identified in this screen may lead to the discovery of novel genes underpinning C4 photosynthesis. These can be used to engineer a C4 photosynthetic pathway into rice.

scholarly journals Estimating the interconversion between CO2 and organic matter in the environment using mathematical models and some considerations

2020 ◽  
Vol 17 (1) ◽  
pp. 56-67
Author(s):  
Tomás Aquino Portes
Keyword(s):  
Organic Chemistry ◽  
Organic Matter ◽  
Mathematical Models ◽  
Chemical Reactions ◽  
Co2 Concentration ◽  
Compensation Point ◽  
Photosynthetic Organisms ◽  
Co2 Compensation Point ◽  
The Earth ◽  
Organic Products

The aims was to use mathematical models to analyze the interconversion between the amount of organic matter produced and the consequent variation in the concentration of CO2 in the atmosphere and to discuss, supported by the data presented and the literature, possible changes in the Earth's environment. Scientific findings and evidence indicate that the concentrations of CO2 and O2 varied throughout the existence of the Earth. These variations were a consequence of the existing environment in different Eras, resulting in changes in all other processes that depended on these gases. Chemical reactions occurred and organic products such as petroleum arose abiotically. These products gave origin to organic chemistry and drastically reduced the concentration of CO2 and elevated O2 in the atmosphere. In the current plants, for each O2 produced in the photochemical step of photosynthesis, one CO2 is assimilated in the biochemical step. Supported by this relationship and by the results presented in this work, it can be inferred that the first photosynthetic organisms originated on Earth when the concentration of CO2 was possibly at a concentration below 1000 ppm. Biochemistry started with these organisms. The results suggest that the reduction in CO2 concentration was linear in relation to the age of the Earth, before the origin of photosynthetic organisms. This relationship changed with origin of these organisms, due to the major changes that occurred in the environment. There is evidence that in certain periods, CO2 concentrations have been reduced below the CO2 compensation point for certain plants resulting in the extinction of these plants and the organisms that depended on them.

scholarly journals Evaluation of ambient mass spectrometry tools for assessing inherent postharvest pepper quality

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Tyler J. Mason ◽  
Harmonie M. Bettenhausen ◽  
Jacqueline M. Chaparro ◽  
Mark E. Uchanski ◽  
Jessica E. Prenni
Keyword(s):  
Mass Spectrometry ◽  
High Throughput ◽  
High Throughput Screening ◽  
Direct Analysis ◽  
Quality Characteristics ◽  
Ambient Mass Spectrometry ◽  
Postharvest Quality ◽  
Ionization Mass ◽  
Ambient Conditions ◽  
Assess Quality

AbstractHorticulturists are interested in evaluating how cultivar, environment, or production system inputs can affect postharvest quality. Ambient mass spectrometry approaches enable analysis of minimally processed samples under ambient conditions and offer an attractive high-throughput alternative for assessing quality characteristics in plant products. Here, we evaluate direct analysis in real time (DART-MS) mass spectrometry and rapid evaporative ionization-mass spectrometry (REIMS) to assess quality characteristics in various pepper (Capsicum annuum L.) cultivars. DART-MS exhibited the ability to discriminate between pod colors and pungency based on chemical fingerprints, while REIMS could distinguish pepper market class (e.g., bell, lunchbox, and popper). Furthermore, DART-MS analysis resulted in the putative detection of important bioactive compounds in human diet such as vitamin C, p-coumaric acid, and capsaicin. The results of this study demonstrate the potential for these approaches as accessible and reliable tools for high throughput screening of pepper quality.

The influence of red and blue light on the rate of photosynthesis and the CO2 compensation point at various oxygen concentrations

1970 ◽  
Vol 48 (6) ◽  
pp. 1251-1257 ◽  
Author(s):  
N. P. Voskresenskaya ◽  
G. S. Grishina ◽  
S. N. Chmora ◽  
N. M. Poyarkova
Keyword(s):  
Nicotiana Tabacum ◽  
Blue Light ◽  
Photosynthetic Rate ◽  
Prolonged Exposure ◽  
Red Light ◽  
Compensation Point ◽  
Gas Analyzer ◽  
Co2 Compensation Point ◽  
Rate Of Photosynthesis ◽  
Light Inhibition

Apparent photosynthesis of attached leaves of Phaseolus vulgaris, Vicia faba, Pisum sativum, and Nicotiana tabacum at various intensities of blue and red light was measured by infrared CO2 gas analyzer in a closed system. Simultaneously the CO2 compensation point was measured.It was found that light-limited photosynthetic rate in blue light was equal to or more than that in red light. Inhibition of photosynthesis, which sometimes occurred at light-saturated intensities of blue light, could be avoided by addition of red light, prolonged exposure of the plants to blue light, or by lowering the O2 concentration. Accordingly, the increase of photosynthetic rate due to change of O2 concentration from 21 to 3% O2 is higher in blue light only when photosynthesis is inhibited by blue light at 21% O2. The data on the action of blue and red light on the CO2 compensation point seems to exclude the activation of photorespiration by blue light.The possible effects of blue light on apparent photosynthesis are discussed on the basis of the results presented.

scholarly journals Measurement and modelling of the dynamics of NH<sub>3</sub> surface-atmosphere exchange over the Amazonian rainforest

2020 ◽  
Author(s):  
Robbie Ramsay ◽  
Chiara F. Di Marco ◽  
Mathew R. Heal ◽  
Matthias Sörgel ◽  
Paulo Artaxo ◽  
...  
Keyword(s):  
Tropical Rainforest ◽  
Pearson Correlation ◽  
Single Layer ◽  
Vapour Pressure Deficit ◽  
Compensation Point ◽  
Leaf Wetness ◽  
Regional Modelling ◽  
Surface Exchange ◽  
A Value ◽  
Amazonian Rainforest

Abstract. Local and regional modelling of NH3 surface exchange is required to quantify nitrogen deposition to, and emissions from, the biosphere. However, measurements and model parameterisations for many remote ecosystems – such as tropical rainforest – remain sparse. Using one month of hourly measurements of NH3 fluxes and meteorological parameters over a remote Amazon rainforest site (Amazon Tall Tower Observatory, ATTO), six model parameterisations based on a bi-directional, single-layer, canopy compensation point resistance model were developed to simulate observations of NH3 surface exchange. Canopy resistance was linked to either relative humidity at the canopy level (RHz′0), vapour pressure deficit, or a parameter value based on leaf wetness measurements. The ratio of apoplastic NH4+ to H+ concentration, Γs, during this campaign was inferred to be 38.5 ± 15.8. The parameterisation that reproduced the observed net exchange of NH3 most accurately was the model that used a cuticular resistance (Rw) parameterisation based on leaf wetness measurements and a value of Γs = 50 (Pearson correlation r = 0.71). Conversely, the model that performed the worst at replicating measured NH3 fluxes used an Rw value modelled using (RHz′0) and the inferred value of Γs = 38.5 (r = 0.45). The results indicate that a single layer, canopy compensation point model is appropriate for simulating NH3 fluxes from tropical rainforest during the Amazonian dry season, and confirmed that a direct measurement of (a non-binary) leaf wetness parameter improves the ability to estimate Rw. Current inferential methods for determining Γs were noted as having difficulties in the humid conditions present at a rainforest site.

scholarly journals Launch Velocities in Successful Golf Putting: An Analytical Analysis

2017 ◽  
Vol 5 (2) ◽  
pp. 24
Author(s):  
John F. Mahoney ◽  
Daniel P. Connaughton
Keyword(s):  
Critical Value ◽  
Theoretical Studies ◽  
Newtonian Mechanics ◽  
Ambient Conditions ◽  
Analytical Analysis ◽  
Bouncing Ball ◽  
Golf Putting ◽  
A Value ◽  
Special Case

Background: This study is concerned with the special case of a putted ball intersecting a standard golf hole at its diameter. The velocity of the ball at the initial rim of the hole is termed the launch velocity and depending upon its value the ball may either be captured or it may escape capture by jumping over the hole. The critical value of the launch velocity (V) is such that lesser values result in capture while greater values produce escape. Purpose: Since the value of the V entered prominently in some theoretical studies of putting, the aim of the current study is to provide an original re-evaluation of V and to contrast our results with existing results. Method: This analytical analysis relies on trigonometry in conjunction with Newtonian mechanics and the mathematics of projectiles. The results of a recent study into the mathematics of a bouncing ball which included the notions of restitution and friction were also employed in the analysis. Results: If bouncing and slipping do not occur when the ball hits the far rim of the hole our analysis produces a value of V of 1.356 m/s. When bouncing and slipping are present we find that V is at least 1.609 m/s but increases beyond this value as slipping and friction become greater. Useful relations which relate the dynamics and geometry of the ball to V are provided. Conclusion: Since ambient conditions may influence the extent of bounce and slippage we conjecture that the value of V is not unique.

Assimilate Source-Sink Relationships in Capsicum annuum L. III. The Effects of Fruit Excision on Photosynthesis and Leaf and Stem Carbohydrates.

1978 ◽  
Vol 5 (1) ◽  
pp. 1 ◽  
Author(s):  
AJ Hall ◽  
FL Milthorpe
Keyword(s):  
Control Mechanism ◽  
Dark Respiration ◽  
Soluble Sugars ◽  
Co2 Concentration ◽  
Co2 Uptake ◽  
Factors Affecting ◽  
Co2 Compensation Point ◽  
Time Period ◽  
Internal Co2 ◽  
Source Sink

Removal of the rapidly growing fruit from a Capsicum plant reduced the rate of net CO2 uptake by its leaves by up to 30% during the time period explored (0.5 - 7 days). This reduction was associated with increases in both the leaf (to about 200%) and intracellular (to about 30%) resistances, these changes having about equal effects on reducing the rate of CO2 uptake. Changes in photorespiration, dark respiration and CO2 compensation point were very small. The rate of CO2 uptake and the associated resistances were also changed by modifying the light regime and other factors affecting the source-sink balance. Changes in the leaf resistance were not attributable to variations in the internal CO2 concentration or in the water economy of the leaf; its control mechanism remains unexplained. The concentration of soluble sugars in the source leaf was completely unaffected but that of polysaccharides was changed by defruiting and by 50% defoliation. However, variations in the intracellular resistance were not closely related to these changes and there is yet no evidence of the nature of its control mechanism. Changes in both soluble sugars and polysaccharides in the stem were more pronounced than in the leaves.

scholarly journals Impact of CO2 concentration and ambient conditions on microalgal growth and nutrient removal from wastewater by a photobioreactor

2019 ◽  
Vol 662 ◽  
pp. 662-671 ◽  
Author(s):  
Fares Almomani ◽  
Ahmed Al Ketife ◽  
Simon Judd ◽  
Mohamed Shurair ◽  
Rahul R. Bhosale ◽  
...  
Keyword(s):  
Nutrient Removal ◽  
Co2 Concentration ◽  
Ambient Conditions

scholarly journals A cyanobacterial photorespiratory bypass model to enhance photosynthesis by rerouting photorespiratory pathway in C3 plants

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ghazal Khurshid ◽  
Anum Zeb Abbassi ◽  
Muhammad Farhan Khalid ◽  
Mahnoor Naseer Gondal ◽  
Tatheer Alam Naqvi ◽  
...  
Keyword(s):  
Kinetic Model ◽  
Inorganic Phosphate ◽  
Elevated Level ◽  
Photosynthetic Efficiency ◽  
C3 Plants ◽  
Simultaneous Increase ◽  
Photosynthetic Pathway ◽  
Bisphosphate Carboxylase ◽  
Toxic Compound ◽  
Overall Efficiency

AbstractPlants employ photosynthesis to produce sugars for supporting their growth. During photosynthesis, an enzyme Ribulose 1,5 bisphosphate carboxylase/oxygenase (Rubisco) combines its substrate Ribulose 1,5 bisphosphate (RuBP) with CO2 to produce phosphoglycerate (PGA). Alongside, Rubisco also takes up O2 and produce 2-phosphoglycolate (2-PG), a toxic compound broken down into PGA through photorespiration. Photorespiration is not only a resource-demanding process but also results in CO2 loss which affects photosynthetic efficiency in C3 plants. Here, we propose to circumvent photorespiration by adopting the cyanobacterial glycolate decarboxylation pathway into C3 plants. For that, we have integrated the cyanobacterial glycolate decarboxylation pathway into a kinetic model of C3 photosynthetic pathway to evaluate its impact on photosynthesis and photorespiration. Our results show that the cyanobacterial glycolate decarboxylation bypass model exhibits a 10% increase in net photosynthetic rate (A) in comparison with C3 model. Moreover, an increased supply of intercellular CO2 (Ci) from the bypass resulted in a 54.8% increase in PGA while reducing photorespiratory intermediates including glycolate (− 49%) and serine (− 32%). The bypass model, at default conditions, also elucidated a decline in phosphate-based metabolites including RuBP (− 61.3%). The C3 model at elevated level of inorganic phosphate (Pi), exhibited a significant change in RuBP (+ 355%) and PGA (− 98%) which is attributable to the low availability of Ci. Whereas, at elevated Pi, the bypass model exhibited an increase of 73.1% and 33.9% in PGA and RuBP, respectively. Therefore, we deduce a synergistic effect of elevation in CO2 and Pi pool on photosynthesis. We also evaluated the integrative action of CO2, Pi, and Rubisco carboxylation activity (Vcmax) on A and observed that their simultaneous increase raised A by 26%, in the bypass model. Taken together, the study potentiates engineering of cyanobacterial decarboxylation pathway in C3 plants to bypass photorespiration thereby increasing the overall efficiency of photosynthesis.

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