scholarly journals Response of Photosynthetic Performance to Drought Duration and Re-Watering in Maize

Agronomy ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 533
Author(s):  
Yuying Jia ◽  
Wanxin Xiao ◽  
Yusheng Ye ◽  
Xiaolin Wang ◽  
Xiaoli Liu ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Electron Transport ◽  
Energy Dissipation ◽  
Quantum Yield ◽  
Photosynthetic Electron Transport ◽  
Photosynthetic Performance ◽  
Electron Acceptors ◽  
Drought Duration ◽  
Acceptor Side ◽  
Antioxidase Activity

The drought tolerance and capacity to recover after drought are important for plant growth and yield. In this study, two maize lines with different drought resistance were used to investigate the effects of different drought durations and subsequent re-watering on photosynthetic capacity, electron transfer and energy distribution, and antioxidative defense mechanisms of maize. Under short drought, maize plants decreased stomatal conductance and photosynthetic electron transport rate, and increased NPQ (Non-photochemical quenching) to dissipate excess excitation energy in time and protect the photosynthetic apparatus. With the increased drought duration, NPQ, antioxidase activity, PItotal (total performance index), ∆I/Io, ψEo (quantum yield for electron transport), φEo (efficiency/probability that an electron moves further than QA−), δRo (efficiency/probability with which an electron from the intersystem electron carriers is transferred to reduce end electron acceptors at the PSI acceptor side) and φRo (the quantum yield for the reduction of the end electron acceptors at the PSI acceptor side) were significantly reduced, while Y(NO) (quantum yield of nonregulated energy dissipation) and MDA (malondialdehyde) began to quickly increase. The photosynthetic rate and capacity of photosynthetic electron transport could not recover to the level of the plants subjected to normal water status after re-watering. These findings indicated that long drought damaged the PSI (photosystem I) and PSII (photosystem II) reaction center and decreased the electron transfer efficiency, and this damage could not be recovered by re-watering. Different drought resistance and recovery levels of photosynthetic performance were achieved by different maize lines. Compared with D340, D1798Z had higher NPQ and antioxidase activity, which was able to maintain functionality for longer in response to progressive drought, and it could also recover at more severe drought after re-watering, which indicated its higher tolerance to drought. It was concluded that the capacity of the energy dissipation and antioxidant enzyme system is crucial to mitigate the effects caused by drought, and the capacity to recover after re-watering was dependent on the severity and persistence of drought, adaptability, and recovery differences of the maize lines. The results provide a profound insight to understand the maize functional traits’ responses to drought stresses and re-watering.

Outdoor cultivation of Ulva lactuca in a recently developed ring-shaped photobioreactor: effects of elevated CO2 concentration on growth and photosynthetic performance

2019 ◽  
Vol 62 (2) ◽  
pp. 179-190 ◽  
Author(s):  
Stefan Sebök ◽  
Werner B. Herppich ◽  
Dieter Hanelt
Keyword(s):  
Electron Transport ◽  
Energy Dissipation ◽  
Algal Growth ◽  
Photosynthetic Electron Transport ◽  
Photosynthetic Performance ◽  
Ulva Lactuca ◽  
Marine Macroalgae ◽  
Quantum Yields ◽  
Ps Ii ◽  
Cultivation Vessel

Abstract Land-based cultivation of marine macroalgae may open up the possibility to produce high quality algal biomass as required in various application areas all year round. In this context, the potential of a recently developed ring-shaped cultivation system with algae moving in a circular way, simulating the movement pattern in a standard tank cultivation vessel was evaluated using the green alga Ulva lactuca. Plants were cultivated under outdoor conditions at ambient (37 μmol CO2 kg−1 seawater) and increased CO2 concentration (152 μmol CO2 kg−1 seawater). Biomass growth and photosynthetic performance of algae were analyzed over a test period of 7 d. Elevated CO2 concentration significantly stimulated algal growth and also helped to compensate the effects of environmental stress conditions. This was indicated by the predominant stability of photosynthetic competence and represented by maximum photosynthetic electron transport rates, efficiency of light-harvesting and photon fluence rates (PFR) saturating photosynthetic electron transport at low PFR. At high PFR, no difference in photosynthetic competence was detected between algae cultivated at the high CO2-concentration and those grown at ambient CO2. Under elevated CO2 concentrations, photochemical energy dissipation decreased more distinctly at low PFR. This may reflect a declining energy demand necessary to maintain photosynthetic capacity. Under elevated CO2, the apparent changes in the quantum yields of regulated and unregulated non-photochemical energy dissipation of PS II at high PFR possibly reflected the enhanced capacity of photoprotection under the prevailing environmental conditions.

On the Mechanism of Benzoquinone Penetration and Photoreduction by Whole Cells

1971 ◽  
Vol 26 (6) ◽  
pp. 585-588 ◽  
Author(s):  
H. Gimmler ◽  
M. Avron
Keyword(s):  
Electron Transport ◽  
Cell Membrane ◽  
Photosynthetic Electron Transport ◽  
Electron Acceptors ◽  
Electron Donors ◽  
Porphyridium Cruentum ◽  
Whole Cells ◽  
Time Treatment ◽  
Short Time

Short time treatment of intact Porphyridium cruentum cells with benzoquinone results in changes of the cell membranes, which lead to a higher permeability. This increased permeability allows the measurements of photosynthetic electron transport reactions with various electron donors, ac. ceptors and mediators, which cannot enter untreated cells. The capacity of benzoquinone to act as a Hill - reagent in vivo is interpreted as due to a double action of this compound: changing the permeability of the cells by reacting with the cell membrane coupled with the ability of the unreacted molecules to serve as electron acceptors.

Kinetics of the photochemical reactions of the croconate dianion in aqueous solution

1992 ◽  
Vol 70 (1) ◽  
pp. 135-143 ◽  
Author(s):  
B Zhao ◽  
M. H. Back
Keyword(s):  
Aqueous Solution ◽  
Electron Transfer ◽  
Quantum Yield ◽  
Rate Constants ◽  
Photochemical Reactions ◽  
Electron Acceptors ◽  
Basic Solution ◽  
Hydroxyl Ion ◽  
Kinetics Of

The kinetics of the photochemical reactions of the dianion of croconic acid (1,2-dihydroxycyclopentenetrione) have been studied in aqueous solution in the presence of electron acceptors. In neutral solutions the quantum yield for disappearance of croconate dianion was small (< 10−3) but was substantially increased in basic solution and in the presence of electron acceptors. At pH 12 in the presence of 4-nitrobenzylbromide and biacetyl a quantum yield of 1 was obtained. The kinetics of the rate of disappearance of croconate dianion as a function of pH and concentration of acceptor showed that the excited dianion is oxidized by acceptors and reacts with hydroxyl ion. A mechanism is proposed that, by assuming reasonable values for the rate constants involved, is shown to be consistent with the results. Keywords: photolysis, kinetics, croconate dianion, electron transfer.

Light-induced Electron Transfer from Tris(2,2′-bipyridine)ruthenium(II)2+ to a Nickeldithiolene in Homogeneous and Heterogeneous Systems

1982 ◽  
Vol 37 (11) ◽  
pp. 1253-1258 ◽  
Author(s):  
Rudolf Frank ◽  
Hermann Rau
Keyword(s):  
Electron Transfer ◽  
Electron Transport ◽  
Quantum Yield ◽  
Anionic Surfactants ◽  
Ruthenium Complex ◽  
Direct Electron Transfer ◽  
Heterogeneous Systems ◽  
Micelle Formation ◽  
Homogeneous System ◽  
Compartment System

We have investigated the reduction of Nickel-tetraphenyldithiolene by 2-aminonaphthalene with Ru(bipy)32+ as a photocatalyst and found a quantum yield of approximately 1 % for the conditions of our homogeneous system. The lifetime of Ru(bipy)32+ is increased from 600 to 800 ns when micelle formation in aqueous solutions of anionic surfactants takes place. No such change.in lifetime is found in nonionic micelles. In a three compartment system the light driven electron transport from one aqueous compartment containing the Ru(bipy)32+/EDTA system through a membrane containing Ni-dithiolene in an organic solvent to tbe second aqueous compartment containing Na3[Fe(CN)6] is investigated. It is shown that direct electron transfer from the excited ruthenium complex to Ni-dithiolene across the phase boundary can be effected by the action of an anionic surfactant.

scholarly journals Action of Some Organomercury Compounds on Photosynthesis in Spinach Chloroplasts

2013 ◽  
Vol 20 (3) ◽  
pp. 489-498 ◽  
Author(s):  
František Šeršeň ◽  
Katarína Kráľová
Keyword(s):  
Photosynthetic Apparatus ◽  
Photosynthetic Electron Transport ◽  
Aqueous Solubility ◽  
Electron Acceptors ◽  
Dmso Solution ◽  
Spinach Chloroplasts ◽  
Acceptor Side ◽  
Methylmercuric Chloride ◽  
Organomercury Compounds ◽  
Sites Of Action

Abstract The effects of five organomercury compounds (methylmercuric chloride, phenylmercuric acetate, phenylmercuric borate, phenylmercuric citrate and diphenylmercury) on photosynthetic electron transport (PET) in spinach chloroplasts were investigated. The IC50 values of organomercury compounds related to PET inhibition in spinach chloroplasts varied in the range from 468 mmol dm-3 to 942 mmol dm-3 and were approximately by one order higher than the corresponding value determined for HgCl2 applied also in DMSO solution (IC50 = 58 mmol dm-3). Due to extremely low aqueous solubility of diphenylmercury, the corresponding IC50 value could not be determined. Using EPR spectroscopy as probable sites of action of organomercury compounds in photosynthetic apparatus ferredoxin on the acceptor side of PS 1 and the quinone electron acceptors QA or QB on the reducing side of PS 2 were suggested.

Examination of pre-industrial and future [CO2] reveals the temperature-dependent CO2 sensitivity of light energy partitioning at PSII in eucalypts

2010 ◽  
Vol 37 (11) ◽  
pp. 1041 ◽  
Author(s):  
Barry A. Logan ◽  
Carolyn R. Hricko ◽  
James D. Lewis ◽  
Oula Ghannoum ◽  
Nathan G. Phillips ◽  
...  
Keyword(s):  
Electron Transport ◽  
Energy Dissipation ◽  
Fluorescence Emission ◽  
Photosynthetic Electron Transport ◽  
Co2 Assimilation ◽  
Energy Partitioning ◽  
O2 Evolution ◽  
Tree Seedlings ◽  
Temperature Dependent ◽  
Photosynthetic O2 Evolution

We grew faster-growing Eucalyptus saligna Sm. and slower-growing Eucalyptus sideroxylon A. Cunn ex Woolls tree seedlings in sunlit glasshouses at all combinations of 290 µL L–1 (pre-industrial), 400 µL L–1 (modern) or 650 µL L–1 (future) global atmospheric CO2 ([CO2]), and ambient or ambient + 4°C temperature. To assess photosynthetic performance, we simultaneously measured light-saturated CO2 assimilation (Asat) and chlorophyll fluorescence emission along with the capacity for photosynthetic O2 evolution and leaf pigment composition. Photosynthetic response to [CO2] was similar between species. Increasing [CO2] but not temperature increased Asat. The response of photosynthetic electron transport to [CO2] was temperature-dependent and manifested through adjustments in energy partitioning at PSII. Increasing [CO2] resulted in greater PSII operating efficiencies at the elevated temperature. We observed no associated acclimatory adjustments in the capacity for photosynthetic O2 evolution or changes in leaf chlorophyll content. Photoprotective energy dissipation responded to increasing [CO2] and temperature. Across species and treatments, increased energy partitioning to electron transport was always associated with decreased partitioning to energy dissipation. Our results suggest that in response to increasing [CO2] and temperature, E. saligna and E. sideroxylon meet increased demands for the products of electron transport via adjustments in energy partitioning, not through acclimation of the capacity for photosynthetic electron transport or light absorption.

Environmental Effects on the Relationship Between the Quantum Yields of Carbon Assimilation and in vivo PsII Electron Transport in Maize

1991 ◽  
Vol 18 (3) ◽  
pp. 267 ◽  
Author(s):  
JP Krall ◽  
GE Edwards
Keyword(s):  
Electron Transport ◽  
Energy Dissipation ◽  
Quantum Yield ◽  
High Energy ◽  
Co2 Assimilation ◽  
Quantum Yields ◽  
Photon Flux ◽  
Ps Ii ◽  
C4 Species ◽  
The Relationship

The partitioning of light energy absorbed by photosystem (PS) II in the C4 species maize was investigated under various photosynthetic photon flux densities (PPFD), temperatures, and intercellular CO2 concentrations. The relationship between the quantum yield of PSII electron transport (�e) and the quantum yield of CO2 assimilation (ΦCO2) was generally found to be linear, with similar slopes. This indicates that PSII electron transport is tightly coupled to CO2 assimilation such that measurements of �e may be used to estimate photosynthetic rates in maize. Coefficients of quenching of PSII chlorophyll fluorescence indicated that, under excessive PPFD or when CO2 assimilation was decreased due to suboptimal or supraoptimal temperature or low Ci, the energy in excess of that needed to drive the reduced rate of PSII electron transport was dissipated via a mechanism known to be correlated to the trans-thylakoid proton gradient (high energy quenching, qE) and a mechanism believed to arise in the PSII antenna chlorophyll (qN(slow)). At suboptimal temperature the energy dissipation was principally at the antenna level and qE was low, while at supraoptimal temperature the reverse was true. The results are discussed relative to coupling of PSII activity to CO2 fixation and mechanisms of energy dissipation in this C4 species.

Photochemistry, energy dissipation and cold-hardening in Eucalyptus nitens and E. pauciflora

1998 ◽  
Vol 25 (5) ◽  
pp. 581 ◽  
Author(s):  
Mark J. Hovenden ◽  
Charles R. Warren
Keyword(s):  
Electron Transport ◽  
Energy Dissipation ◽  
Low Temperatures ◽  
Heat Dissipation ◽  
Photosynthetic Electron Transport ◽  
Thermal Dissipation ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Eucalyptus Nitens ◽  
Dissipation Processes

The allocation of absorbed photon energy to thermal energy dissipation and photosynthetic electron transport was investigated as a function of photosynthetic photon flux density (PPFD) and temperature in two species of subalpine eucalypt, Eucalyptus nitens (Deane et Maiden) Maiden and E. pauciflora Sieb. ex Spreng. The proportion of absorbed light utilised in photosynthetic electron transport decreased with increasing PPFD, and the decrease was more pronounced the lower the temperature. The proportion diverted into dissipation processes increased with increasing PPFD to a maximum where it reached a plateau. This maximum increased with decreasing temperature. Exposure to a succession of cold (4˚C) nights increased the photochemical quantum yield of photosystem II and decreased the allocation of excitation energy to thermal dissipation processes in conditions of excess light, particularly at low temperatures. Consequently, the photosynthetic electron transport rate (ETR) was higher and heat dissipation rate (HDR) was lower in hardened plants than in non-hardened plants at low temperatures. At 20˚C, ETR was generally higher than HDR in all plants, but as the temperature decreased, HDR became the dominant process. The PPFD at which HDR exceeded ETR decreased with decreasing temperature, and at low temperatures was always lower in non-hardened plants than hardened plants, although quite similar between species.

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