scholarly journals Physiological Characteristics of Photosynthesis in Yellow-Green, Green and Dark-Green Chinese Kale (Brassica oleracea L. var. alboglabra Musil.) under Varying Light Intensities

Plants ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 960
Author(s):  
Kuan-Hung Lin ◽  
Feng-Chi Shih ◽  
Meng-Yuan Huang ◽  
Jen-Hsien Weng
Keyword(s):  
Electron Transport ◽  
Energy Dissipation ◽  
Light Intensity ◽  
Thermal Energy ◽  
Electron Transport Rate ◽  
Transport Rate ◽  
Physiological Characteristics ◽  
Chinese Kale ◽  
Thermal Energy Dissipation ◽  
Dark Green

The objective of this work was to study physiological characteristics and photosynthetic apparatus in differentially pigmented leaves of three Chinese kale cultivars. Chlorophyll (Chl) fluorescence and photochemical reflectance index (PRI) measurements in green, yellow-green, and dark-green cultivars in response to varying light intensities. As light intensity increased from 200 to 2000 photosynthetic photon flux density (PPFD), fraction of light absorbed in photosystem (PS) II and PRI values in all plants were strongly lowered, but fraction of light absorbed in PSII dissipated via thermal energy dissipation and non-photochemical quenching (NPQ) values in all plants wereremarkably elevated.When plants were exposed to 200 PPFD, the values of fraction of light absorbed in PSII, utilized in photosynthetic electron transport(p), andfraction of light absorbed excitation energy in PSII dissipated via thermal energy dissipation (D), remained stable regardless of the changes in levels of Chla + b. Under 800 and 1200 PPFD, the values of p and electron transport rate (ETR) decreased, but D and NPQ increased as Chla + bcontent decreased, suggesting that decrease inChla + bcontent led to lower PSII efficiency and it became necessary to increase dissipate excess energy. On the contrary, in 2000 PPFD, leaves with lower Chla + bcontent had relatively higher p and electron transport rate (ETR) values and lower D level, as well as tended to increase more in NPQ but decrease more in PRI values. The consistent relations between PRI and NPQ suggest that NPQ is mainly consisted ofthe xanthophyll cycle-dependentenergy quenching.Yellow-green cultivar showed lower Chla + bcontent but high carotenoids/Chla + b ratio and had high light protection ability under high PPFD. The precise management of photosynthetic parameters in response to light intensity can maximize the growth and development of Chinese kale plants.

scholarly journals Novel Remote Sensing Index of Electron Transport Rate Predicts Primary Production and Crop Health in L. sativa and Z. mays

2020 ◽  
Vol 12 (11) ◽  
pp. 1718
Author(s):  
Oded Liran ◽  
Ofer M. Shir ◽  
Shai Levy ◽  
Ariel Grunfeld ◽  
Yuval Shelly
Keyword(s):  
Remote Sensing ◽  
Electron Transport ◽  
Light Intensity ◽  
Vegetation Index ◽  
Photosynthetic Activity ◽  
Electron Transport Rate ◽  
Photosynthetic Performance ◽  
Field Conditions ◽  
Transport Rate ◽  
Response Curves

Photosynthesis performance can be assessed quantitatively with light response curves. These curves record the Electron Transport Rate (ETR) as a function of light intensity. Then, statistical fit on these curves parameterize light use efficiency, maximum photosynthetic activity and the reaction of the apparatus to stress. While this technique is performed with portable fluorometers in field conditions, it is difficult to scale it to the canopy level. The Fraunhofer line discrimination technique, which detects fluorescence signals emitted during photosynthesis, is a promising method to assess photosynthetic performance of canopies. In this study, we define a remote sensing ETR index based on a combination of three parameters: sun-induced fluorescence, normalized differential vegetation index and light intensity. Two representatives of C3 and C4 photosynthesis, L. sativa and Z. mays, experienced a fertilization concentrations gradient. ETR increased with light intensity in both crops. In L. sativa, ETR assumed a linear relationship between the photosynthetic activity and light intensity, with a correlation of R2 = 0.99 to the portable fluorometer. Additional parametrization revealed a resilience of its reaction centers to photoinhibition in maximum light intensities. When Z. mays experienced open field conditions, ETR correlated with the plant’s status. While the results of this study are promising, the index still requires validation in terms of temporal track and spatial variability.

Thermal-Energy Dissipation

1982 ◽  
Vol 70 (4) ◽  
pp. 475-480 ◽  
Author(s):  
Kenneth H. Cohn ◽  
James W. May
Keyword(s):  
Energy Dissipation ◽  
Thermal Energy ◽  
Thermal Energy Dissipation

Thermal Energy Dissipation by SiO2-Coated Plasmonic-Superparamagnetic Nanoparticles in Alternating Magnetic Fields

2013 ◽  
Vol 25 (22) ◽  
pp. 4603-4612 ◽  
Author(s):  
Georgios A. Sotiriou ◽  
Michelle A. Visbal-Onufrak ◽  
Alexandra Teleki ◽  
Eduardo J. Juan ◽  
Ann M. Hirt ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Magnetic Fields ◽  
Thermal Energy ◽  
Superparamagnetic Nanoparticles ◽  
Thermal Energy Dissipation ◽  
Alternating Magnetic Fields

scholarly journals Updating the steady state model of C4 photosynthesis

2021 ◽  
Author(s):  
Susanne von Caemmerer
Keyword(s):  
Steady State ◽  
Electron Transport ◽  
Electron Transport Rate ◽  
Transport Rate ◽  
Initial Slope ◽  
Carboxylase Activity ◽  
Quantitative Correlation ◽  
Steady State Model ◽  
State Models

AbstractC4 plants play a key role in world agriculture. For example, C4 crops such as maize and sorghum are major contributors to both first and third world food production and the C4 grasses sugarcane; miscanthus and switchgrass are major plant sources of bioenergy. In the challenge to manipulate and enhance C4 photosynthesis, steady state models of leaf photosynthesis provide and important tool for gas exchange analysis and thought experiments that can explore photosynthetic pathway changes. Here the C4 photosynthetic model by von Caemmerer and Furbank (1999) has been updated with new kinetic parameterisation and temperature dependencies added. The parameterisation was derived from experiments on the C4 monocot, Setaria viridis, which for the first time provides a cohesive parametrisation. Mesophyll conductance and its temperature dependence have also been included, as this is an important step in the quantitative correlation between the initial slope of the CO2 response curve of CO2 assimilation and in vitro PEP carboxylase activity. Furthermore, the equations for chloroplast electron transport have been updated to include cyclic electron transport flow and equations have been added to calculate electron transport rate from measured CO2 assimilation rates.HighlightThe C4 photosynthesis model by von Caemmerer and Furbank (1999) has been updated. It now includes temperature dependencies and equations to calculate electron transport rate from measured CO2 assimilation rates.

scholarly journals Mefenpyr-diethyl as a safener for haloxyfop-methyl in bahiagrass

2021 ◽  
Author(s):  
Roque de Carvalho Dias ◽  
Leandro Bianchi ◽  
Vitor Muller Anunciato ◽  
Leandro Tropaldi ◽  
Paulo Vinicius da Silva ◽  
...  
Keyword(s):  
Electron Transport ◽  
Protective Effect ◽  
Plant Height ◽  
Electron Transport Rate ◽  
Transport Rate ◽  
Low Doses ◽  
Protective Response ◽  
Randomized Design ◽  
Dry Biomass ◽  
Completely Randomized Design

Abstract Mefenpyr-diethyl is a foliar-acting safener of the pyrazoline chemical group, and after its absorption, the metabolization and detoxification of herbicides occur in treated plants. Studies have demonstrated the protective effect of this safener for the herbicide fenoxaprop-P-ethyl in grass. Thus, this work aimed to evaluate whether a tank mixture of mefenpyr-diethyl has a protective response to haloxyfop-methyl in non-perennial bahiagrass. The experiment had a completely randomized design and was carried out in a greenhouse, using five replications with a 10x2 factorial scheme and ten doses of haloxyfop-methyl (0.00, 0.24, 0.49, 0.97, 1.95, 3.90, 7.79, 15.59, 31.28, and 62.35 g a.i. ha-1) in the presence or absence of a tank mixture of mefenpyr-diethyl (50 g a.i. ha-1). Phytotoxicity and electron transport rate (ETR) were evaluated at 7, 14, 21, and 28 days after application (DAA), in addition to plant height and dry biomass at 28 DAA. In general, phytotoxicity increased due to the higher levels of the herbicide haloxyfop-methyl. The application of mefenpyr-diethyl, in turn, provided lower levels of phytotoxicity, as well as lower reductions in ETR, height, and dry biomass when compared to untreated plants. These results show the safener action of a tank mixture of mefenpyr-diethyl on low doses of haloxyfop-methyl in non-perennial bahiagrass.

Wide variation of winter-induced sustained thermal energy dissipation in conifers: a common-garden study

Oecologia ◽  
2021 ◽  
Author(s):  
A. Walter-McNeill ◽  
M. A. Garcia ◽  
B. A. Logan ◽  
D. M. Bombard ◽  
J. S. Reblin ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Thermal Energy ◽  
Common Garden ◽  
Thermal Energy Dissipation
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