Photochemistry and xanthophyll cycle-dependent energy dissipation in differently oriented cladodes of Opuntia stricta during the winter

1998 ◽  
Vol 25 (1) ◽  
pp. 95 ◽  
Author(s):  
David H. Barker ◽  
Barry A. Logan ◽  
William W. Adams III ◽  
Barbara Demmig-Adams
Keyword(s):  
Energy Dissipation ◽  
Excitation Energy ◽  
Xanthophyll Cycle ◽  
Photosynthetic Apparatus ◽  
High Rate ◽  
Psii Efficiency ◽  
Thermal Energy Dissipation ◽  
Dramatic Decline ◽  
Absorption Of Light ◽  
Cycle Dependent

The photosynthetic and energy dissipation responses of four differently oriented photosynthetic surfaces (cladodes) from the cactus Opuntia stricta (Haw.) Haw. were studied in the field during the winter in Australia. Even under very low PFD (i.e. -2 s-1) all surfaces experienced a dramatic decline in photosystem II (PSII) efficiency during the morning period when temperatures were below freezing. However, light energy absorbed during the warmer afternoon period was more efficiently utilised for photochemistry with less diversion through the thermal energy dissipation pathway. Low temperature presumably reduced the proportion of excitation energy that could be utilised photosynthetically, resulting in a high rate of energy dissipation with a concomitant decline in PSII efficiency. A lag in the diurnal de-acidification of malic acid, and therefore the availability of endogenous CO2, may have also contributed to the low rate of photochemistry during the morning period. We interpret the increase in energy dissipation and decline in PSII efficiency as a controlled response of PSII that is dependent upon the de-epoxidised components of the xanthophyll cycle under conditions when the absorption of light exceeds the capacity of the photosynthetic apparatus to process the excitation energy through photochemistry.

Xanthophyll cycle, light energy dissipation and photosystem II down-regulation in senescent leaves of wheat plants grown in the field

2001 ◽  
Vol 28 (10) ◽  
pp. 1023 ◽  
Author(s):  
Congming Lu ◽  
Qingtao Lu ◽  
Jianhua Zhang ◽  
Qide Zhang ◽  
Tingyun Kuang
Keyword(s):  
Energy Dissipation ◽  
Photosystem Ii ◽  
Excitation Energy ◽  
Xanthophyll Cycle ◽  
Light Energy ◽  
Photochemical Quenching ◽  
Down Regulation ◽  
Psii Efficiency ◽  
Psii Photochemistry ◽  
Assimilation Capacity

Photosynthesis, the xanthophyll cycle, light energy dissipation and down-regulation of photosystem II (PSII) in senescent leaves of wheat plants grown in the field were investigated. With the progress of senescence, maximal efficiency of PSII photochemistry decreased only slightly early in the morning but substantially at midday. Actual PSII efficiency, photochemical quenching, efficiency of excitation capture by open PSII centres, and the I–P phase of fluorescence induction curves decreased significantly and such decreases were much more evident at midday than in the morning. At the same time, non-photochemical quenching, thermal dissipation and de-epoxidation status of the xanthophyll cycle increased, with much greater increases at midday than in the morning. These results suggest that the xanthophyll cycle played a role in photoprotection of PSII in senescent leaves by dissipating excess excitation energy. Taking into account the substantial decrease in photosynthetic capacity in senescent leaves, our data seem to support the view that the decrease in actual PSII efficiency in senescent leaves may represent a mechanism to down-regulate photosynthetic electron transport to match the decreased CO2 assimilation capacity and avoid photodamage of PSII from excess excitation energy.

Effects of lincomycin on PSII efficiency, non-photochemical quenching, D1 protein and xanthophyll cycle during photoinhibition and recovery

2004 ◽  
Vol 31 (8) ◽  
pp. 803 ◽  
Author(s):  
Kristine Mueh Bachmann ◽  
Volker Ebbert ◽  
William W. Adams III ◽  
Amy S. Verhoeven ◽  
Barry A. Logan ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Thermal Energy ◽  
Xanthophyll Cycle ◽  
D1 Protein ◽  
Light Treatment ◽  
High Light ◽  
Low Light ◽  
Psii Efficiency ◽  
High Light Treatment ◽  
Thermal Energy Dissipation

Leaves of Parthenocissus quinquefolia (L.) Planch. (Virginia creeper) were treated with lincomycin (an inhibitor of chloroplast-encoded protein synthesis), subjected to a high-light treatment and allowed to recover in low light. While lincomycin-treated leaves had similar characteristics as controls after a 1 h exposure to high light, total D1 levels in lincomycin-treated leaves were half those in controls at the end of the recovery period. In addition, lincomycin delayed recovery of maximal PSII efficiency of open centers (ratio of variable to maximal chlorophyll fluorescence, F v / F m) and of estimated PSII photochemistry rate upon return to low light subsequent to the high-light treatment. Furthermore, lincomycin treatment slowed the removal of zeaxanthin (Z) and antheraxanthin (A) during recovery in low light, and the level of thermal energy dissipation (non-photochemical fluorescence quenching, NPQ) remained elevated. In lincomycin-treated leaves infiltrated with the uncoupler nigericin immediately after high-light exposure, thermal energy dissipation, sustained with lincomycin alone, declined quickly to control levels. In summary, lincomycin treatment affected not only D1 protein turnover but also xanthophyll-cycle operation and thermal-energy dissipation. The latter effect was apparently a result of the maintenance of a high trans-thylakoid proton gradient. Similar effects were also seen subsequent to short-term exposures to high light in lincomycin-treated Spinacia oleracea L. (spinach) leaves. In contrast, lincomycin treatments under low-light levels did not induce Z formation or NPQ. These results suggest that lincomycin has the potential to lower PSII efficiency (F v / F m) through inhibition of NPQ relaxation and Z + A removal subsequent to high-light exposures.

Xanthophyll Cycle-Dependent Energy Dissipation and Flexible Photosystem II Efficiency in Plants Acclimated to Light Stress

1995 ◽  
Vol 22 (2) ◽  
pp. 249 ◽  
Author(s):  
B Demmig-Adams ◽  
WW Iii Adams ◽  
BA Logan ◽  
AS Verhoeven
Keyword(s):  
Energy Dissipation ◽  
Photosystem Ii ◽  
Xanthophyll Cycle ◽  
Light Stress ◽  
Photon Flux ◽  
Growth Environment ◽  
Psii Efficiency ◽  
Cycle Dependent ◽  
Shade Leaves ◽  
Sun Leaves

The effect of an acclimation to light stress during the growth of leaves on their response to high photon flux densities (PFDs) was characterised by quantifying changes in photosystem II (PSII) characteristics and carotenoid composition. During brief experimental exposures to high PFDs sun leaves exhibited: (a) much higher levels of antheraxanthin + zeaxanthin than shade leaves, (b) a greater extent of energy dissipation in the light-harvesting antennae, and (c) a greater decrease of intrinsic PSII efficiency that was rapidly reversible. During longer experimental exposures to high PFD, deep-shade leaves but not the sun leaves showed slowly developing secondary decreases in intrinsic PSII efficiency. Recovery of these secondary responses was also slow and inhibited by lincomycin, an inhibitor of chloroplast-encoded protein synthesis. In contrast, under field conditions all changes in intrinsic PSII efficiency in open sun-exposed habitats as well as understory sites with intense sunflecks appeared to be caused by xanthophyll cycle-dependent energy dissipation. Furthermore, comparison of leaves with different maximal rates of electron transport revealed that all leaves compensated fully for these differences by dissipating very different amounts of absorbed light via xanthophyll cycle-dependent energy dissipation, thereby all maintaining a similarly low PSII reduction state. It is our conclusion that an increased capacity for xanthophyll cycle-dependent energy dissipation is a key component of the acclimation of leaves to a variety of different forms of light stress, and that the response of leaves to excess light experienced in the growth environment is thus likely to be qualitatively different from that to sudden experimental exposures to PFDs exceeding the growth PFD.

Water relations, chlorophyll fluorescence, and membrane permeability during desiccation in bryophytes from xeric, mesic, and hydric environments

1998 ◽  
Vol 76 (11) ◽  
pp. 1923-1929 ◽  
Author(s):  
Vicente I Deltoro ◽  
Angeles Calatayud ◽  
Cristina Gimeno ◽  
Eva Barreno
Keyword(s):  
Chlorophyll Fluorescence ◽  
Energy Dissipation ◽  
Water Content ◽  
Thermal Energy ◽  
Membrane Damage ◽  
Photosynthetic Apparatus ◽  
Fluorescence Emission ◽  
Conocephalum Conicum ◽  
Thermal Energy Dissipation ◽  
Fluorescence Characteristics

The interactions among water content, chlorophyll a fluorescence emission, and potassium leakage were analyzed during dehydration in desiccation-tolerant bryophytes from xeric habitats (Hedwigia ciliata (Hedw.) P. Beauv., Hypnum cupressiforme Hedw., Leucodon sciuroides (Hedw.) Schwaegr., Orthotrichum cupulatum Brid., Pleurochaete squarrosa (Brid.) Lindb., Porella platyphylla (L.) Pfeiff., and Tortula ruralis (Hedw.) Gaertn., Meyer & Scherb.) and desiccation-intolerant bryophytes from mesic and hydric environments (Barbula ehrenbergii (Lor.) Fleisch., Cinclidotus aquaticus (Hedw.) B. & S., Conocephalum conicum (L.) Underw., Lunularia cruciata (L.) Dum. ex Lindb., Palustriella commutata (Hedw.) Ochyra, Philonotis calcarea (B. & S.) Schimp., and Rhynchostegium riparioides (Hedw.) Card.). Their fluorescence characteristics at low water content were low efficiency of photosynthetic quantum conversion, closed photosystem II reaction centers, and strong nonphotochemical quenching only in desiccation-tolerant species. Full restoration of fluorescence parameters upon rewatering in species from xeric environments indicated that the photosynthetic apparatus was fully functional after desiccation. Species from hydric and mesic habitats were unable to restore photochemical activity. This might be a consequence of photoinhibition but also of membrane damage, as indicated by the large leakage of potassium. It is suggested that the capacity to enhance thermal energy dissipation during dehydration might have evolved in species from xeric environments as an adaptation to the utilization of an erratic supply of water. This protective strategy would lower the probability of photodamage during water loss and thus maintain the photosynthetic apparatus in a quickly recuperable state.Key words: bryophytes, chlorophyll fluorescence, dehydration, desiccation tolerance, thermal energy dissipation.

scholarly journals Mechanisms shaping the synergism of zeaxanthin and PsbS in photoprotective energy dissipation in the photosynthetic apparatus of plants

2021 ◽  
Author(s):  
Renata Welc ◽  
Rafal Luchowski ◽  
Dariusz Kluczyk ◽  
Monika Zubik ◽  
Wojciech Grudzinski ◽  
...  
Keyword(s):  
Excitation Energy ◽  
Xanthophyll Cycle ◽  
Molecular Mechanisms ◽  
Molecular Spectroscopy ◽  
Imaging Techniques ◽  
Photophysical Properties ◽  
Photosynthetic Apparatus ◽  
Strong Light ◽  
Thylakoid Membrane Proteins ◽  
Photo Damage

AbstractSafe operation of photosynthesis is vital to plants and is ensured by the activity of numerous processes protecting chloroplasts against photo-damage. The harmless dissipation of excess excitation energy is believed to be the main photoprotective mechanism and is most effective with the simultaneous presence of PsbS protein and zeaxanthin, a xanthophyll accumulated in strong light as a result of the xanthophyll cycle activity. Here we address the problem of specific molecular mechanisms underlying the synergistic effect of zeaxanthin and PsbS. The experiments were conducted with Arabidopsis thaliana, the wild-type and the mutants lacking PsbS (npq4) and affected in the xanthophyll cycle (npq1), with the application of multiple molecular spectroscopy and imaging techniques. Research results lead to the conclusion that PsbS interferes with the formation of tightly packed aggregates of thylakoid membrane proteins, thus enabling the incorporation of xanthophyll cycle pigments into such structures. It was found that xanthophylls trapped within supramolecular structures, most likely in the interfacial protein region, determine their photophysical properties. The structures formed in the presence of violaxanthin are characterized by minimized dissipation of excitation energy. In contrast, the structures formed in the presence of zeaxanthin show enhanced excitation quenching, thus protecting the system against photo-damage.

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