Journal articles: 'Photo-acclimation'

1

Hojo, Masaya, Masao Tasaka, and Toshiharu Shikanai. "Physiological requirements of the nonmevalonate pathway for photo-acclimation in Arabidopsis." Plant Biotechnology 22, no. 1 (2005): 39–45. http://dx.doi.org/10.5511/plantbiotechnology.22.39.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Tanno, Yuri, Shota Kato, Senji Takahashi, Shun Tamaki, Shinichi Takaichi, Yutaka Kodama, Kintake Sonoike, and Tomoko Shinomura. "Light dependent accumulation of β-carotene enhances photo-acclimation of Euglena gracilis." Journal of Photochemistry and Photobiology B: Biology 209 (August 2020): 111950. http://dx.doi.org/10.1016/j.jphotobiol.2020.111950.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Watson, Tim L., Dugald C. Close, Neil J. Davidson, and Noel W. Davies. "Pigment dynamics during cold-induced photoinhibition of Acacia melanoxylon." Functional Plant Biology 31, no. 5 (2004): 481. http://dx.doi.org/10.1071/fp03209.

Full text

Abstract:

Long-term acclimation of photo- and pigment-chemistry was investigated in a naturally-regenerating stand of Acacia melanoxylon R.Br. ex Ait. A pronounced decrease in photochemical efficiency of A. melanoxylon saplings was observed between autumn and winter in both thinned and unthinned treatments, but the decrease was more severe in the thinned treatment. Associated pigment changes in the unthinned treatment included a decrease in total chlorophyll content and a rise in chlorophyll a : b. Similar acclimation occurred in the thinned treatment with additional increase in zeaxanthin per unit chlorophyll observed. Saplings in the thinned treatment were exposed to lower minimum temperatures, more hours of frost and higher light intensities in the mid- to lower-crown. Growth chamber studies of the short-term acclimation of photo- and pigment-chemistry were conducted in a low / high light and cold / warm temperature factorial experiment. Photochemical efficiency and quantum yield adjusted within one day and then remained constant for 10 d in response to the imposed treatments. Chlorophyll concentration had decreased in all treatments by day 2 in the growth chambers, and subsequently increased in warm, but not in cold, treatments, irrespective of light level by day 10 in the growth chambers. The concentration of lutein-5,6-epoxide decreased in response to the cold-high light treatment and increased in response to other treatments by day 10 in the growth chambers, consistent with a function in sustained photoprotection in leaves of shade-adapted species. Our experiments indicated that A. melanoxylon is susceptible to cold-induced photoinhibition under cool temperatures (2–8°C) and moderate light intensities (450 μmol m–2 s–1).

APA, Harvard, Vancouver, ISO, and other styles

4

Bahamondes Dominguez, Angela A., Anna E. Hickman, Robert Marsh, and C. Mark Moore. "Constraining the response of phytoplankton to zooplankton grazing and photo-acclimation in a temperate shelf sea with a 1-D model – towards S2P3 v8.0." Geoscientific Model Development 13, no. 9 (September 4, 2020): 4019–40. http://dx.doi.org/10.5194/gmd-13-4019-2020.

Full text

Abstract:

Abstract. An established one-dimensional Shelf Sea Physics and Primary Production (S2P3) model has been developed into three different new models: S2P3-NPZ which includes a nutrient–phytoplankton–zooplankton (NPZ) framework, where the grazing rate is no longer fixed but instead varies over time depending on different functions chosen to represent the predator–prey relationship between zooplankton and phytoplankton; S2P3-Photoacclim which includes a representation of the process of photo-acclimation and flexible stoichiometry in phytoplankton; and S2P3 v8.0 which combines the NPZ framework and the variable stoichiometry of phytoplankton at the same time. These model formulations are compared to buoy and conductivity–temperature–depth (CTD) observations, as well as zooplankton biomass and in situ phytoplankton physiological parameters obtained in the central Celtic Sea (CCS). Models were calibrated by comparison to observations of the timing and magnitude of the spring phytoplankton bloom, magnitude of the spring zooplankton bloom, and phytoplankton physiological parameters obtained throughout the water column. A sensitivity study was also performed for each model to understand the effects of individual parameters on model dynamics. Results demonstrate that better agreement with biological observations can be obtained through the addition of representations of photo-acclimation, flexible stoichiometry, and grazing provided these can be adequately constrained.

APA, Harvard, Vancouver, ISO, and other styles

5

Tuya, Fernando, Séfora Betancor, Federico Fabbri, Fernando Espino, and Ricardo Haroun. "Photo-physiological performance and short-term acclimation of two coexisting macrophytes (Cymodocea nodosa and Caulerpa prolifera) with depth." Scientia Marina 80, no. 2 (June 9, 2016): 247–59. http://dx.doi.org/10.3989/scimar.04391.07a.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Titlyanov, E. A., T. V. Titlyanova, K. Yamazato, and R. van Woesik. "Photo-acclimation dynamics of the coral Stylophora pistillata to low and extremely low light." Journal of Experimental Marine Biology and Ecology 263, no. 2 (August 2001): 211–25. http://dx.doi.org/10.1016/s0022-0981(01)00309-4.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Hu, Qian, Matthew Turnbull, and Ian Hawes. "Salinity restricts light conversion efficiency during photo-acclimation to high irradiance in Stuckenia pectinata." Environmental and Experimental Botany 165 (September 2019): 83–91. http://dx.doi.org/10.1016/j.envexpbot.2019.05.022.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Straka, Levi, and Bruce E. Rittmann. "Light attenuation changes with photo-acclimation in a culture of Synechocystis sp. PCC 6803." Algal Research 21 (January 2017): 223–26. http://dx.doi.org/10.1016/j.algal.2016.11.024.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Arora, Rajeev, and Lisa J. Rowland. "Physiological Research on Winter-hardiness: Deacclimation Resistance, Reacclimation Ability, Photoprotection Strategies, and a Cold Acclimation Protocol Design." HortScience 46, no. 8 (August 2011): 1070–78. http://dx.doi.org/10.21273/hortsci.46.8.1070.

Full text

Abstract:

Freezing is a major environmental stress during an annual cycle of overwintering, temperate-zone perennials. The timing and extent of seasonal cold acclimation (development of freezing tolerance in the fall) and deacclimation (loss of acquired freezing tolerance in response to warm temperatures) are of critical importance for winter survival, particularly in view of the climate change, i.e., unpredictable extreme weather occurrences. For example, plants may acclimate inadequately if exposed to a milder fall climate and may be damaged by sudden frosts. Alternatively, they may deacclimate prematurely as a result of unseasonable, midwinter warm spells and be injured by the cold that follows. Efficient cold acclimation ability, high deacclimation resistance, and efficient reacclimation capacity are, therefore, important components of winter survival in overwintering perennials. These components should be evaluated separately for a successful breeding program focused on improving winter-hardiness. Another layer of complexity that should be carefully considered is that endodormant status (shallow versus deep) of the reproductive/vegetative apices can significantly impact these components of winter-hardiness. Winter survival, especially by woody evergreens, requires tolerance of light stress, which can result in photo-oxidative damage at cold temperatures when biochemistry of photosynthesis is somewhat compromised but light harvesting is unaffected. Accumulation of Elips (early light-induced proteins) in overwintering evergreens during winter represents a relatively novel strategy to cope with such light stress, and investigations on the precise cellular mechanism and genetic control of this strategy deserve research in the future. Investigations into the mechanisms for cold acclimation use laboratory-based, artificial acclimation protocols that often do not closely approximate conditions that plants are typically exposed to in nature. To draw meaningful conclusions about the biology of cold acclimation and ultimately improve freeze resistance under field conditions, one should also include in cold acclimation regimens parameters such as exposure to subfreezing temperatures and realistic diurnal temperature fluctuations and light levels to simulate natural conditions. One of the main objectives of this article is to highlight two areas of research that we believe are important in the context of plant cold-hardiness but, so far, have not received much attention. These are: 1) to understand the biology of deacclimation resistance and reacclimation capacity, two important components of freeze-stress resistance (winter-hardiness) in woody perennials; and 2) to investigate the cellular basis for various strategies used by broad-leaved evergreens for photoprotection during winter. Our emphasis, in this context, is on a family of proteins, called Elips. The second objective of this article is to draw attention of the cold-hardiness research community to the importance of using realistic cold acclimation protocols in controlled environments that will approximate natural/field conditions to be better able to draw meaningful conclusions about the biology of cold acclimation and ultimately improve freeze resistance. Results from our work with Rhododendron (deciduous azaleas and broad-leaved evergreens), blueberry, and that of other researchers are discussed to support these objectives.

APA, Harvard, Vancouver, ISO, and other styles

10

Titlyanov, E. A., T. V. Titlyanova, K. Yamazato, and R. van Woesik. "Photo-acclimation of the hermatypic coral Stylophora pistillata while subjected to either starvation or food provisioning." Journal of Experimental Marine Biology and Ecology 257, no. 2 (March 2001): 163–81. http://dx.doi.org/10.1016/s0022-0981(00)00308-7.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Pierangelini, Mattia, Slobodanka Stojkovic, Philip T. Orr, and John Beardall. "Photo-acclimation to low light—Changes from growth to antenna size in the cyanobacterium Cylindrospermopsis raciborskii." Harmful Algae 46 (June 2015): 11–17. http://dx.doi.org/10.1016/j.hal.2015.04.004.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Malea, Lamprini, Konstantinia Nakou, Apostolos Papadimitriou, Athanasios Exadactylos, and Sotiris Orfanidis. "Physiological Responses of the Submerged Macrophyte Stuckenia pectinata to High Salinity and Irradiance Stress to Assess Eutrophication Management and Climatic Effects: An Integrative Approach." Water 13, no. 12 (June 20, 2021): 1706. http://dx.doi.org/10.3390/w13121706.

Full text

Abstract:

Stuckenia pectinata, a submerged macrophyte of eutrophic to hyper-eutrophic fresh to brackish waters, faces management and climatic-forced increment of salinity and irradiance in Vistonis Lake (Greece) that may endanger its existence and the ecosystem functioning. A pre-acclimated clone under low irradiance and salinity conditions was treated to understand the effects of high salinity and irradiance on a suite of subcellular (chlorophyll a fluorescence kinetics and JIP-test, and chlorophyll content) to organismal (relative growth rate—RGR) physiological parameters. The responses to high irradiance indicated the plant’s great photo-acclimation potential to regulate the number and size of the reaction centers and the photosynthetic electron transport chain by dissipation of the excess energy to heat. A statistically significant interaction (p < 0.01) of salinity and irradiance on Chl a, b content indicated acclimation potential through adjusting the Chl a, b contents. However, no significant (p > 0.05) difference was observed on Chl a/b ratio and the RGR, indicating the species’ potential to become acclimatized by reallocating resources to compensate for growth. Thus, the regulation of photosynthetic pigment content and photosystem II performance consisted of the primary growth strategy to present and future high salinity and irradiance stressful conditions due to eutrophication management and the ongoing climatic changes.

APA, Harvard, Vancouver, ISO, and other styles

13

Savitch, Leonid V., Angelo Massacci, Gordon R. Gray, and Norman P. A. Huner. "Acclimation to low temperature or high light mitigates sensitivity to photoinhibition: roles of the Calvin cycle and the Mehler reaction." Functional Plant Biology 27, no. 3 (2000): 253. http://dx.doi.org/10.1071/pp99112.

Full text

Abstract:

Winter wheat (Triticum aestivum L cv. Monopol) plants grown under either control (20˚C, 250 PFD), low temperature (5˚C, 250 PFD) or high light conditions (20˚C, 800 PFD) were compared in order to assess the roles of the Calvin cycle and the Mehler reaction in the differential sensitivity to chronic photoinhibition. Despite similar photosynthetic responses to irradiance, the partial pressure of CO2 [p(CO2)] and photoinhibition, photosynthetic acclimation to cold temperature appears to be quite distinct from acclimation to high light. First, the lower ratio of Rubisco oxygenation/Rubisco carboxylation and the reduced effects of p(CO2) on number of electrons per mole of CO2 fixed in cold-acclimated compared to high light-grown wheat indicate that photorespiration is differentially suppressed in cold-acclimated Monopol. Second, inhibition of the Calvin cycle by glyceraldehyde during photo-inhibition indicated that the sensitivity of high light-acclimated Monopol to photoinhibition was more dependent on Rubisco activity than the sensitivity of cold-acclimated plants to photoinhibition. Third, cold-acclimated Monopol exhibited higher electron transport rates in the presence of either ambient CO2, 2 kPa O2 or N2, 2 kPa O2 (either 77% or 68%, respectively) relative to controls compared to high light-acclimated plants exposed to similar gaseous environments (either 57% or 38%, respectively). Last, the activation state of NADP–malate dehydrogenase indicated that the stroma is highly reduced during cold acclimation relative to either controls or high light-grown Monopol. Thus, in cold-acclimated wheat, the Mehler reaction appears to play an important role while photorespiration plays a minimal role in mitigating the sensitivity to photoinhibition. In contrast, both photorespiration and the Mehler reac-tion appear to mitigate the sensitivity to photoinhibition in high light-grown Monopol. This is consistent with the differential sensitivity to methylviologen and the differential SOD activity observed between cold-acclimated and high light-grown Monopol.

APA, Harvard, Vancouver, ISO, and other styles

14

Ross, ON, and RJ Geider. "New cell-based model of photosynthesis and photo-acclimation: accumulation and mobilisation of energy reserves in phytoplankton." Marine Ecology Progress Series 383 (May 14, 2009): 53–71. http://dx.doi.org/10.3354/meps07961.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Shi, Qin, Yunlong Yin, Zhiquan Wang, Wencai Fan, and Jianfeng Hua. "Physiological Acclimation of Taxodium Hybrid ‘Zhongshanshan 118’ Plants to Short-term Drought Stress and Recovery." HortScience 51, no. 9 (September 2016): 1159–66. http://dx.doi.org/10.21273/hortsci10997-16.

Full text

Abstract:

The physiological acclimation of Taxodium hybrid ‘zhongshanshan 118’ (T.118) plants to a progressive drought stress and drought-stressed to recovery treatment (DS-R) was investigated in this study. Plants of control (C) treatment were watered daily throughout the experiment. Results indicated that water deficit reduced stomatal conductance (gS) to improve water use efficiency (WUE) and, as a consequence, net photosynthetic rate (Pn), transpiration rate (Tr), and intercellular CO2 concentration (Ci) were also decreased in DS-R T.118 plants compared with C plants. These reductions became more significant with decreasing soil water availability. Correlation analysis showed gS was positively correlated (P < 0.01) with the soil water content as well as leaf relative water content (RWC). There was a tendency to accumulate proline, malondialdehyde (MDA), antioxidases, and membrane electrolyte leakage as stress intensity increased. Moreover, drought stress induced significant (P < 0.05) decline in total chlorophyll contents (Chlt) and increase of nonphotochemical quenching (NPQ) on day 8 as a photo-protective mechanism. Cluster analysis distinguished the adaption of T.118 plants to water deficit in two ways. First, photosynthesis was related to thermal dissipation, and second antioxidation was related to morphology and osmosis. Furthermore, tested parameters showed a reversed tendency and restored equivalently to C levels after 9 days of rewatering. These findings suggest that T.118 plants demonstrated considerable tolerance to short-term drought stress and recovery due to a high degree of plasticity in physiological acclimation.

APA, Harvard, Vancouver, ISO, and other styles

16

Mullineaux, Philip, Louise Ball, Carolina Escobar, Barbara Karpinska, Gary Creissen, and Stanislaw Karpinski. "Are diverse signalling pathways integrated in the regulation of Arabidopsis antioxidant defence gene expression in response to excess excitation energy?" Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 355, no. 1402 (October 29, 2000): 1531–40. http://dx.doi.org/10.1098/rstb.2000.0713.

Full text

Abstract:

When low–light–grown Arabidopsis rosettes are partially exposed to excess light (EL), the unexposed leaves become acclimated to excess excitation energy (EEE) and consequent photo–oxidative stress. This phenomenon, termed systemic acquired acclimation (SAA), is associated with redox changes in the proximity of photosystem II, changes in foliar H 2 O 2 content and induction of antioxidant defences. The induction of extra–plastidial antioxidant systems is important in the protection of the chloroplast under EL conditions. A larger range of transcripts encoding different antioxidant defence enzymes may be induced in the systemically acclimated leaves and these include those encoded by the glutathione peroxidase ( GPX2 ) and glutathione–S–transferase ( GST ) genes, which are also highly induced in the hypersensitive response and associated systemic acquired resistance (SAR) in incompatible plantpathogen interactions. Furthermore, the expression of the SAR–inducible pathogenesis–related protein gene, PR2 , is enhanced in SAA leaves. Wounded leaf tissue also shows enhanced systemic induction of a cytosolic ascorbate peroxidase gene ( APX2 ) under EL conditions. These and other considerations, suggest H 2 O 2 and other reactive oxygen species (ROS) could be the common factor in signalling pathways for diverse environmental stresses. These effects may be mediated by changes in the level and redox state of the cellular glutathione pool. Mutants with constitutive expression of a normally EL–inducible APX2 gene have much reduced levels of foliar glutathione. The expression of APX1 and APX3 , encoding cytosolic and peroxisome–associated isoforms, respectively, are also under phytochrome–A–mediated control. The expression of these genes is tightly linked to the greening of plastids in etiolated seedlings. These data suggest that part of the developmental processes that bring about the acclimation of leaves to high light includes the configuration of antioxidant defences. Therefore, the linkage between immediate responses of leaves to EL, acclimation of chloroplasts to EEE and the subsequent changes to leaf form and function in high light could be mediated by the activity of foliar antioxidant defences and changes in the concentration of ROS.

APA, Harvard, Vancouver, ISO, and other styles

17

Lin, Binle, K. Futono, A. Yokoi, M. Hosomi, and A. Murakami. "Effects of activated carbon on treatment of photo-processing waste by sulfur-oxidizing bacteria." Water Science and Technology 35, no. 7 (April 1, 1997): 187–95. http://dx.doi.org/10.2166/wst.1997.0276.

Full text

Abstract:

Establishing economic treatment technology for safe disposal of photo-processing waste (PW) has most recently become an urgent environmental concern. This paper describes a new biological treatment process for PW using sulfur-oxidizing bacteria (SOB) in conjunction with activated carbon (AC). Batch-type acclimation and adsorption experiments using SOB/PAC, SOB/PNAC, and SOB reactor type systems demonstrated that AC effectively adsorbs the toxic/refractory compounds which inhibit thiosulfate oxidization of SOB in PW. Thus, to further clarify the effect of AC, we performed a long-term (≈ 160 d) continuous-treatment experiment on 4- to 8-times dilution of PW using a SOB/GAC system which simulated a typical wastewater treatment system based on an aerobic activated sludge process that primarily uses acclimated SOB. The thiosulfate load and hydraulic retention time (HRT) were fixed during treatment such that they ranged from 0.8-3.7 kg S2O32-/l/d and 7.7-1.9 d, respectively. As expected, continuous treatment led to breakthrough of the adsorption effect of GAC. Renewing the GAC and continuing treatment for about 10 d demonstrated good treatment effectiveness.

APA, Harvard, Vancouver, ISO, and other styles

18

LIN, BIN LE, MASAAKI HOSOMI, and AKIHIKO MURAKAMI. "Acclimation of Sulfur-Oxidizing Bacteria to Photo-Processing Waste Containing High-Strength Thiosulfate, Salinity, COD and the Waste Treatment Performance." Japanese Journal of Water Treatment Biology 34, no. 1 (1998): 29–40. http://dx.doi.org/10.2521/jswtb.34.29.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Ayata, S. D., M. Lévy, O. Aumont, A. Sciandra, J. Sainte-Marie, A. Tagliabue, and O. Bernard. "Phytoplankton growth formulation in marine ecosystem models: Should we take into account photo-acclimation and variable stoichiometry in oligotrophic areas?" Journal of Marine Systems 125 (September 2013): 29–40. http://dx.doi.org/10.1016/j.jmarsys.2012.12.010.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

CALIANDRO, ROSANNA, KERSTIN A. NAGEL, BERND KASTENHOLZ, ROBERTO BASSI, ZHIRONG LI, KRISHNA K. NIYOGI, BARRY J. POGSON, ULRICH SCHURR, and SHIZUE MATSUBARA. "Effects of altered α ‐ and β ‐branch carotenoid biosynthesis on photoprotection and whole‐plant acclimation of Arabidopsis to photo‐oxidative stress." Plant, Cell & Environment 36, no. 2 (August 22, 2012): 438–53. http://dx.doi.org/10.1111/j.1365-3040.2012.02586.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Rier, Steven T., R. Jan Stevenson, and Gina D. LaLiberte. "PHOTO-ACCLIMATION RESPONSE OF BENTHIC STREAM ALGAE ACROSS EXPERIMENTALLY MANIPULATED LIGHT GRADIENTS: A COMPARISON OF GROWTH RATES AND NET PRIMARY PRODUCTIVITY1." Journal of Phycology 42, no. 3 (June 2006): 560–67. http://dx.doi.org/10.1111/j.1529-8817.2006.00225.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Kangasjärvi, Saijaliisa, Anna Lepistö, Kati Hännikäinen, Mirva Piippo, Eeva-Maria Luomala, Eva-Mari Aro, and Eevi Rintamäki. "Diverse roles for chloroplast stromal and thylakoid-bound ascorbate peroxidases in plant stress responses." Biochemical Journal 412, no. 2 (May 14, 2008): 275–85. http://dx.doi.org/10.1042/bj20080030.

Full text

Abstract:

Photosynthetic light reactions comprise a significant source of hydrogen peroxide (H2O2) in illuminated leaves. APXs (ascorbate peroxidases) reduce H2O2 to water and play an important role in the antioxidant system of plants. In the present study we addressed the significance of chloroplast APXs in stress tolerance and signalling in Arabidopsis thaliana. To this end, T-DNA (transfer DNA) insertion mutants tapx, sapx and tapx sapx, lacking the tAPX (thylakoid-bound APX), sAPX (stromal APX) or both respectively, were characterized. Photo-oxidative stress during germination led to bleaching of chloroplasts in sapx single-mutant and particularly in the tapx sapx double-mutant plants, whereas the greening process of wild-type and tapx plants was only partially impaired. Mature leaves of tapx sapx double mutants were also susceptible to short-term photo-oxidative stress induced by high light or methyl viologen treatments. After a 2-week acclimation period under high light or under low temperature, none of the mutants exhibited enhanced stress symptoms. Immunoblot analysis revealed that high-light-stress-acclimated tapx sapx double mutants compensated for the absence of tAPX and sAPX by increasing the level of 2-cysteine peroxiredoxin. Furthermore, the absence of tAPX and sAPX induced alterations in the transcriptomic profile of tapx sapx double-mutant plants already under quite optimal growth conditions. We conclude that sAPX is particularly important for photoprotection during the early greening process. In mature leaves, tAPX and sAPX are functionally redundant, and crucial upon sudden onset of oxidative stress. Moreover, chloroplast APXs contribute to chloroplast retrograde signalling pathways upon slight fluctuations in the accumulation of H2O2 in chloroplasts.

APA, Harvard, Vancouver, ISO, and other styles

23

Bednář, Pavel, Jiří Souček, Jan Krejza, and Jakub Černý. "Growth and Morphological Patterns of Norway Spruce (Picea abies (L.) Karst.) Juveniles in Response to Light Intensities." Forests 13, no. 11 (October 29, 2022): 1804. http://dx.doi.org/10.3390/f13111804.

Full text

Abstract:

(1) Background: The growth and morphology of Norway spruce (Picea abies (L.) Karst.) juveniles were observed under different light conditions due to overstory canopy openness. The aim was to investigate the photo-morphological responses of juveniles for the development of a desirable forest structure. The research was located in a higher altitude zone in central Europe. (2) Methods: Light was estimated using hemispherical photographs. Eight different parameters of natural regeneration were measured on individuals within 1 × 1 m around each point on a 3 × 3 m grid. A total of 1214 sapling measurements (from 10 to 431 cm in height) were taken. (3) Results: Light affected the growth and morphological development of juveniles, resulting in variation in the lateral crown growth and crown length. Acclimations manifested as trade-offs between height and lateral crown growth. Similar shifts were found within relative height growth (the terminal length to the total height) and apical dominance ratio (the terminal length to the branch length). The crown length was proven to be highly capable to acclimation. Light influenced the density weakly, however, when a regeneration index (density × median height) was considered, significant relations with light conditions were discovered.

APA, Harvard, Vancouver, ISO, and other styles

24

Artetxe, Unai, Antonio Hernández, José I. García-Plazaola, and José M. Becerril. "Do light acclimation mechanisms reduce the effects of light-dependent herbicides in duckweed (Lemna minor)?" Weed Science 54, no. 02 (April 2006): 230–36. http://dx.doi.org/10.1614/ws-05-54.2.230.

Full text

Abstract:

This research studies whether photoprotection mechanisms are able to counterbalance the short-term effect of two herbicides, acifluorfen methyl (AFM) and paraquat (PQ), that generate photo-oxidative stress in different subcellular locations. Duckweed plants grown under three light intensities (high-, medium-, and low light), and consequently expressing three levels of photoprotection, were exposed to both herbicides under the same light regime. Oxidative damage induced by AFM originated mainly from the cytosolic accumulation of protoporphyrin IX, leading to a process of plasma membrane disruption, a progressive and slow degradation of ascorbate and photosynthetic pigments, and glutathione accumulation. As most photoprotective mechanisms (antioxidants and xanthophylls-cycle-related energy dissipation) operate mainly within the chloroplast, these systems were unable to protect plants from AFM damage irrespective of the level of light acclimation. Paraquat effects developed more rapidly and to a greater extent than AFM in treated plants. Irrespective of the light intensity, the same sequence of degradation was observed: ascorbate followed by glutathione, α-tocopherol, pigments, and membrane disruption. In PQ-treated plants the generation of oxidative stress occurred mainly in the chloroplast, and cellular damage developed more slowly in highly photoprotected plants (high light); in fact, electrolyte leakage can be used as a marker for PQ tolerance. The effects of both herbicides indicate that the xanthophyll cycle is an early protective mechanism and confirms the central role of ascorbate in early photoprotection response. High levels of lipophilic and hydrophilic antioxidant contents did not lead to attenuated phytotoxicity of acifluorfen methyl and thus are not the basis to explain differential susceptibilities among duckweed plants.

APA, Harvard, Vancouver, ISO, and other styles

25

Sánchez-España, Javier, Carmen Falagán, Diana Ayala, and Katrin Wendt-Potthoff. "Adaptation of Coccomyxa sp. to Extremely Low Light Conditions Causes Deep Chlorophyll and Oxygen Maxima in Acidic Pit Lakes." Microorganisms 8, no. 8 (August 11, 2020): 1218. http://dx.doi.org/10.3390/microorganisms8081218.

Full text

Abstract:

Deep chlorophyll maxima (DCM) and metalimnetic oxygen maxima (MOM) are outstanding biogeochemical features of acidic pit lakes (APL). However, knowledge of the eukaryotic phototrophs responsible for their formation is limited. We aimed at linking the dynamics of phototrophic communities inhabiting meromictic APL in Spain with the formation of these characteristic layers. Firstly, the dynamics of DCM and MOM and their relation to physico-chemical parameters (photosynthetically active radiation (PAR), pH, dissolved ferric iron concentration, temperature), pigments and nutrient distribution is described; secondly, the phototrophic community composition is studied through a combination of microscopy, biomolecular and “omics” tools. Phototrophic communities of the studied APL show a low diversity dominated by green microalgae, specifically Coccomyxa sp., which have been successfully adapted to the chemically harsh conditions. DCM and MOM are usually non-coincident. DCM correspond to layers where phototrophs have higher chlorophyll content per cell to cope with extremely low PAR (<1 µmol m−2 s−1), but where photosynthetic oxygen production is limited. MOM correspond to shallower waters with more light, higher phytoplankton biomass and intense photosynthetic activity, which affects both oxygen concentration and water temperature. The main drivers of DCM formation in these APL are likely the need for nutrient uptake and photo-acclimation.

APA, Harvard, Vancouver, ISO, and other styles

26

Adams, James E., Sergio L. Colombo, Catherine B. Mason, Ruby A. Ynalvez, Baran Tural, and James V. Moroney. "A mutant of Chlamydomonas reinhardtii that cannot acclimate to low CO2 conditions has an insertion in the Hdh1 gene." Functional Plant Biology 32, no. 1 (2005): 55. http://dx.doi.org/10.1071/fp04119.

Full text

Abstract:

Photosynthetic microorganisms must acclimate to environmental conditions, such as low CO2 environments or high light intensities, which may lead to photo-oxidative stress. In an effort to understand how photosynthetic microorganisms acclimate to these conditions, Chlamydomonas reinhardtii was transformed using the BleR cassette, selected for Zeocin resistance and screened for colonies that showed poor growth at low CO2 levels. One of the insertional mutants obtained, named slc-230, was shown to have a BleR insert in the first exon of Hdh1, a novel, single copy gene. The predicted Hdh1 gene product has similarity to bacterial haloacid dehalogenase-like proteins, a protein family that includes phosphatases and epoxide hydrolases. In addition, Hdh1 is predicted to be localised to the chloroplast or mitochondria in C. reinhardtii. It was found that a genomic copy of wild type Hdh1 can complement slc-230. Physiological studies were conducted to determine the effects of the altered expression of Hdh1 in slc-230. slc-230 grows slowly autotrophically in low CO2, exhibits a lower affinity for inorganic carbon, a decreasing photosynthetic rate over time and a lower content of chlorophylls and quenching xanthophylls than wild type cells. Some possible roles of Hdh1 in the acclimation to low CO2 conditions are discussed.

APA, Harvard, Vancouver, ISO, and other styles

27

Tomaszewska-Sowa, Magdalena, Norbert Keutgen, Tomáš Lošák, Anna Figas, and Anna J. Keutgen. "Pseudomonas syringae Infection Modifies Chlorophyll Fluorescence in Nicotiana tabacum." Agriculture 12, no. 9 (September 19, 2022): 1504. http://dx.doi.org/10.3390/agriculture12091504.

Full text

Abstract:

The system Nicotiana tabacum L.—Pseudomonas syringae VAN HALL pv. tomato (Pto) DC3000 was investigated at a low inoculation level (c. 5 × 105 colony-forming units (CFU) mL–1) such as it occurs in the field. The aim of this study was to test the hypothesis that N. tabacum, a non-host of Pto DC3000, improved the PSII efficiency in inoculated leaves compared with control detached leaves. Visible symptoms at the infected area were not detected within 14 days. Chlorophyll (Chl) a fluorescence was measured 6–7 days after inoculation of detached leaves. Compared with the control, the actual photochemical quantum yield of photosystem (PS) II was higher in the inoculated leaves at the expense of the fraction of heat dissipated by photo-inactivated non-functional centers. In addition, the fraction of open PSII reaction centers (RCs) was higher in inoculated leaves. Maximum fluorescence in the dark-adapted detached inoculated leaves, as a measure of the absorbed energy, was lower than in control leaves. The lower capacity to absorb energy in combination with a higher fraction of open PSII RCs is interpreted as an acclimation to limit over-excitation and to reduce heat dissipation. This should limit the production of reactive oxygen species and reduce the probability of a hypersensitive response (HR), which represents an expensive cell-death program for the plant.

APA, Harvard, Vancouver, ISO, and other styles

28

Lazzara, L., I. Nardello, C. Ermanni, O. Mangoni, and V. Saggiomo. "Light environment and seasonal dynamics of microalgae in the annual sea ice at Terra Nova Bay, Ross Sea, Antarctica." Antarctic Science 19, no. 1 (February 28, 2007): 83–92. http://dx.doi.org/10.1017/s0954102007000119.

Full text

Abstract:

We investigated the physical conditions of the Spring pack ice environment at Terra Nova Bay to understand their influence on the structure and physiology of sympagic microalgae. Bio-optical methods were used to study the availability and spectral quality of solar radiation, both inside and underneath the ice cover. Pack ice thickness was around 2.5 m, with a temperature between −2 and −7°C. On average, only 1.4% of surface PAR penetrated to the bottom ice and less than 0.6% below platelet ice level. Surface UV-B radiation under the bottom ice was 0.2–0.4%. Biomass concentrations up to 2400 mg Chl a m−3, dominated by two species of diatoms (Entomoneis kjellmannii and Nitschia cf. stellata), showed marked spatial and temporal patterns. Maximum values were in the platelet ice during the first half of November, and in the bottom ice two weeks later. Strong shade adaptation characteristics emerged clearly and explained the relevant abundance of microalgae within the sea ice, with specific absorption coefficients (a*) as low as 0.005 m2 (mg Chl a)−1 and the photo-acclimation index (Ek) in the range of in situ irradiance. The biomass specific production values were low, around 0.12–0.13 mg C mg Chl a−1 h−1. The hypothesis suggesting bottom ice colonization by platelet ice microalgae is supported here.

APA, Harvard, Vancouver, ISO, and other styles

29

Wu, Y., K. Gao, and U. Riebesell. "CO<sub>2</sub>-induced seawater acidification affects physiological performance of the marine diatom <I>Phaeodactylum tricornutum</I>." Biogeosciences Discussions 7, no. 3 (May 25, 2010): 3855–78. http://dx.doi.org/10.5194/bgd-7-3855-2010.

Full text

Abstract:

Abstract. CO2/pH perturbation experiments were carried out under two different pCO2 levels (39.3 and 101.3 Pa) to evaluate effects of CO2-induced ocean acidification on the marine diatom Phaeodactylum tricornutum. After acclimation (>20 generations) to ambient and elevated CO2 conditions (with corresponding pH values of 8.15 and 7.80, respectively), growth and photosynthetic carbon fixation rates of high CO2 grown cells were enhanced by 5% and 12%, respectively, and dark respiration stimulated by 34% compared to cells grown at ambient CO2. The K1/2 (dissolved inorganic carbon, DIC) for carbon fixation increased by 20% under the low pH and high CO2 condition, reflecting a decreased photosynthetic affinity for HCO3− or/and CO2 and down-regulated carbon concentrating mechanism (CCM). In the high CO2 grown cells, the electron transport rate from photosystem II (PSII) was photoinhibited to a greater extent at high levels of photosynthetically active radiation, while non-photochemical quenching was reduced compared to low CO2 grown cells. This was probably due to the down-regulation of CCM, which serves as a sink for excessive energy. Increasing seawater pCO2 and decreasing pH associated with atmospheric CO2 rise may enhance diatom growth, down-regulate their CCM, and enhanced their photo-inhibition and dark respiration. The balance between these positive and negative effects on diatom productivity will be a key factor in determining the net effect of rising atmospheric CO2 on ocean primary production.

APA, Harvard, Vancouver, ISO, and other styles

30

Martin, P., N. Sanwlani, TWQ Lee, JMC Wong, KYW Chang, EWS Wong, and SC Liew. "Dissolved organic matter from tropical peatlands reduces shelf sea light availability in the Singapore Strait, Southeast Asia." Marine Ecology Progress Series 672 (August 19, 2021): 89–109. http://dx.doi.org/10.3354/meps13776.

Full text

Abstract:

Shelf seas provide valuable ecosystem services, but their productivity and ecological functioning depend critically on sunlight transmitted through the water column. Anthropogenic reductions in underwater light availability are thus a serious threat to coastal habitats. The flux of light-absorbing coloured dissolved organic matter (CDOM) from land to sea may have increased world-wide, but how this has altered the availability and spectral quality of light in shelf seas remains poorly known. We present time-series data from the Sunda Shelf in Southeast Asia, where the monsoon-driven reversal in ocean currents supplies water enriched in CDOM from tropical peatlands for part of the year, resulting in 5- to 10-fold seasonal variation in light absorption by CDOM. We show that this terrigenous CDOM can dominate underwater light absorption at wavelengths up to 500 nm, and shift the underwater irradiance spectrum towards longer wavelengths. The seasonal presence of terrigenous CDOM also reduces the 10% light penetration depth by 1-5 m, or 10-45%. We estimate that on average 0.6 m, or 25%, of this terrigenous CDOM-mediated shoaling might be attributable to the enhanced input of dissolved organic matter following peatland disturbance. The seasonal change in the light environment is correlated with changes in phytoplankton absorption spectra that suggest a photo-acclimation response, and we infer that terrigenous CDOM likely contributes to limiting the depth distribution of photosynthetic corals. The results reveal an ecologically important but largely overlooked impact of human modifications to carbon fluxes that is likely increasingly important in coastal seas.

APA, Harvard, Vancouver, ISO, and other styles

31

Demmig-Adams, B., and WW Iii Adams. "Capacity for Energy Dissipation in the Pigment Bed in Leaves With Different Xanthophyll Cycle Pools." Functional Plant Biology 21, no. 5 (1994): 575. http://dx.doi.org/10.1071/pp9940575.

Full text

Abstract:

Photosynthetic capacities, xanthophyll cycle components, and the capacity for photoprotective dissipation of excess excitation in the chlorophyll pigment bed were compared in two groups of species acclimated to different growth irradiance. These were sun leaves of three species with moderately high maximal photosynthetic capacities, tulip, rose, and periwinkle (Vinca minor), and leaves which had developed under very low irradiance from three shade-tolerant species, Monstera deliciosa, Philodendron caudatum and Schefflera arboricola. All sun leaves possessed larger xanthophyll cycle pools and greater maximal zeaxanthin (and antheraxanthin) contents and also displayed a greater maximal capacity for photo-protective energy dissipation in the pigment bed than the leaves acclimated to very low irradiance. The sun leaves also maintained a considerably lower reduction state of photosystem II at full sunlight than the leaves acclimated to very low irradiance. Thus, during exposure to full sunlight, these sun leaves were able to dissipate a major portion of the absorbed light through the combination of photosynthesis and energy dissipation in the pigment bed. Under the same conditions, these two processes combined were able to dissipate only a small fraction of the absorbed light in the leaves acclimated to very low irradiance. Most of the above differences between sun-acclimated leaves and leaves acclimated to very low irradiance existed not only between species but also within a species. Acclimation of Monstera deliciosa to a high growth irradiance resulted in leaves with a larger xanthophyll cycle pool, a greater maximal zeaxanthin (and antheraxanthin) content, and a greater capacity for energy dissipation in the pigment bed.

APA, Harvard, Vancouver, ISO, and other styles

32

Feng, Jing-Qiu, Wei Huang, Ji-Hua Wang, and Shi-Bao Zhang. "Different Strategies for Photosynthetic Regulation under Fluctuating Light in Two Sympatric Paphiopedilum Species." Cells 10, no. 6 (June 10, 2021): 1451. http://dx.doi.org/10.3390/cells10061451.

Full text

Abstract:

Fluctuating light can cause selective photoinhibition of photosystem I (PSI) in angiosperms. Cyclic electron flow (CEF) around PSI and electron flux from water via the electron transport chain to oxygen (the water-water cycle) play important roles in coping with fluctuating light in angiosperms. However, it is unclear whether plant species in the same genus employ the same strategy to cope with fluctuating light. To answer this question, we measured P700 redox kinetics and chlorophyll fluorescence under fluctuating light in two Paphiopedilum (P.) Pftzer (Orchidaceae) species, P. dianthum and P. micranthum. After transition from dark to high light, P. dianthum displayed a rapid re-oxidation of P700, while P. micranthum displayed an over-reduction of P700. Furthermore, the rapid re-oxidation of P700 in P. dianthum was not observed when measured under anaerobic conditions. These results indicated that photo-reduction of O2 mediated by the water-water cycle was functional in P. dianthum but not in P. micranthum. Within the first few seconds after an abrupt transition from low to high light, PSI was highly oxidized in P. dianthum but was highly reduced in P. micranthum, indicating that the different responses of PSI to fluctuating light between P. micranthum and P. dianthum was attributed to the water-water cycle. In P. micranthum, the lack of the water-water cycle was partially compensated for by an enhancement of CEF. Taken together, P. dianthum and P. micranthum employed different strategies to cope with the abrupt change of light intensity, indicating the diversity of strategies for photosynthetic acclimation to fluctuating light in these two closely related orchid species.

APA, Harvard, Vancouver, ISO, and other styles

33

Ma, Feng wang, and Lailiang Cheng*. "Exposure of the Shaded Side of Apple Fruit to Full Sun Leads to Up-regulation of Both the Xanthophyll Cycle and the Ascorbate-glutathione Cycle." HortScience 39, no. 4 (July 2004): 887A—887. http://dx.doi.org/10.21273/hortsci.39.4.887a.

Full text

Abstract:

About 80 days after full bloom, well-exposed fruit on the south part of the canopy of mature Liberty/M.9 apple trees were randomly assigned to one of the following two treatments. Some fruit were turned about 180 degrees to expose the original shaded side to full sun whereas the rest served as untreated controls. On day 0, 1, 2, 4, 7, and 10 after treatment, fruit peel samples were taken from the original shaded side of the treated fruit and both the sun-exposed side and the shaded side of the control fruit at midday to determine photosynthetic pigments and enzymatic and non-enzymatic antioxidants. Maximum photosystem II efficiency of the original shaded side decreased sharply after 1 day exposure to full sun, and then gradually recovered to a similar value of the sun-exposed side of the control fruit by day 10. The shaded side of the control fruit had much lower xanthophyll cycle pool size and conversion and antioxidant enzymes and soluble antioxidants of the ascorbate-glutathione cycle than the sun-exposed side. In response to full sun exposure, xanthophyll cycle pool size of the original shaded side increased, reaching a similar value of the sun-exposed side by day 10. Ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase and total pool size and reduction state of both ascorbate and glutathione of the original shaded side all increased to the corresponding values found in the sun-exposed side of the control fruit over a 10-day period. It is concluded that both xanthophyll cycle and the ascorbate-glutathione cycle in the original shaded side are up-regulated in response to fullsun exposure to minimize photo-oxidative damage and contributes to its re-acclimation to full sun.

APA, Harvard, Vancouver, ISO, and other styles

34

Jones, Alison M., and Ray Berkelmans. "Tradeoffs to Thermal Acclimation: Energetics and Reproduction of a Reef Coral with Heat TolerantSymbiodiniumType-D." Journal of Marine Biology 2011 (2011): 1–12. http://dx.doi.org/10.1155/2011/185890.

Full text

Abstract:

The photo-physiological characteristics of thermo-tolerantSymbiodiniumtypes have been postulated to have negative effects on the energetics of the reef corals by reducing fitness. To investigate this, two key and inextricably coupled indicators of fitness, lipids and reproduction, were monitored in colonies of the broadcast-spawning coralAcropora milleporaover a two-year period that included a natural bleaching event. In the absence of bleaching ITS1-type clade D predominant colonies had 26% lower stored lipids compared to C2 colonies. At spawning time, this correlated with 28% smaller eggs in type-D colonies. This energetic disparity is expected to have reduced larval duration and settlement-competency periods in type-D compared to type-C2 colonies. More importantly, irrespective of the effect of genotype, the fitness of all corals was adversely affected by the stress of the bleaching event which reduced prespawning lipids by 60% and halved the number of eggs compared to the previous year. Our results extend work that has shown that direct temperature stress and symbiont change are likely to work in concert on corals by demonstrating that the lipids and reproduction of the reef building corals on tropical reefs are likely to be impaired by these processes as our climate warms.

APA, Harvard, Vancouver, ISO, and other styles

35

Veres, Katalin, Zsolt Csintalan, Zsanett Laufer, Rita Engel, Krisztina Szabó, and Edit Farkas. "Photoprotection and high-light acclimation in semi-arid grassland lichens – a cooperation between algal and fungal partners." Symbiosis 86, no. 1 (December 9, 2021): 33–48. http://dx.doi.org/10.1007/s13199-021-00823-y.

Full text

Abstract:

AbstractIn lichens, each symbiotic partner cooperates for the survival of the symbiotic association. The protection of the susceptible photosynthetic apparatus is essential for both participants. The mycobiont and photobiont contribute to the protection against the damaging effect of excess light by various mechanisms. The present study investigated the effect of seasonality and microhabitat exposure on photoprotection and photoacclimation in the photo- and the mycobiont of six lichen species with different thallus morphology in inland dune system in the Kiskunság region (Hungary) with shaded, more humid and exposed, drier dune sides. High-Performance Liquid Chromatography, spectrophotometry, chlorophyll a fluorescence kinetic technique were used, and micrometeorological data were collected. The four years data series revealed that the north-east-facing side was characterized by higher relative humidity and lower light intensities compared to the south-west-facing drier and more exposed sides. The south-west facing side was exposed to direct illumination 3–4 hours longer in winter and 1–2 hours shorter in summer than the north-east facing side of the dune, influencing the metabolism of sun and shade populations of various species. Because rapid desiccation caused short active periods of lichens during bright and drier seasons and on exposed microhabitats, the rapid, non-regulated non-photochemical quenching mechanisms in the photobiont had a significant role in protecting the photosynthetic system in the hydrated state. In dehydrated conditions, thalli were mainly defended by the solar screening metabolites produced by the mycobiont and curling during desiccation (also caused by the mycobiont). Furthermore, the efficacy of light use (higher chlorophyll and carotenoid concentration) increased because of short hydrated periods. Still, a lower level of received irradiation was appropriate for photosynthesis in dry seasons and on sun exposed habitats. In humid seasons and microhabitats, more extended active periods lead to increased photosynthesis and production of solar radiation protectant fungal metabolites, allowing a lower level of photoprotection in the form of regulated non-photochemical quenching by the photobiont. Interspecific differences were more pronounced than the intraspecific ones among seasons and microhabitat types.

APA, Harvard, Vancouver, ISO, and other styles

36

Barbedo, Lucas, Simon Bélanger, Jennifer V. Lukovich, Paul G. Myers, and Jean-Éric Tremblay. "Atmospheric forcing and photo-acclimation of phytoplankton fall blooms in Hudson Bay." Elementa: Science of the Anthropocene 10, no. 1 (2022). http://dx.doi.org/10.1525/elementa.2021.00067.

Full text

Abstract:

Pulses of ocean primary productivity during the fall season are frequent in the mid-latitudes when ocean cooling and wind-driven turbulence erode the surface stratification and allow the injection of nutrients into the euphotic zone. This phenomenon is often referred to as a phytoplankton fall bloom, and can play an essential role in the survival of marine species during winter. In Hudson Bay, we found that pelagic fall blooms are triggered when the convective mixing, forced mainly by atmospheric cooling and to a lesser extent to wind-driven turbulence, expands the mixed layer, ventilates the pycnocline, and likely erodes the nitracline. Ocean color observations were used to assess the seasonal variability of phytoplankton photo-acclimation state from the ratio of phytoplankton carbon (Cphy) to chlorophyll-a concentration ([chla]). Cphy was estimated using the satellite-derived particulate backscattering coefficient (bbp) after subtraction of the non-algal backscattering background. We found a systematic increase in Cphy and Cphy:[chla] from mid-summer to fall season indicating that fall blooms are potentially productive in term of organic carbon fixation.

APA, Harvard, Vancouver, ISO, and other styles

37

Kuo, Eva YuHua, and Tse-Min Lee. "Molecular Mechanisms Underlying the Acclimation of Chlamydomonas reinhardtii Against Nitric Oxide Stress." Frontiers in Plant Science 12 (August 5, 2021). http://dx.doi.org/10.3389/fpls.2021.690763.

Full text

Abstract:

The acclimation mechanism of Chlamydomonas reinhardtii to nitric oxide (NO) was studied by exposure to S-nitroso-N-acetylpenicillamine (SNAP), a NO donor. Treatment with 0.1 or 0.3 mM SNAP transiently inhibited photosynthesis within 1 h, followed by a recovery, while 1.0 mM SNAP treatment caused irreversible photosynthesis inhibition and mortality. The SNAP effects are avoided in the presence of the NO scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-l-oxyl-3-oxide (cPTIO). RNA-seq, qPCR, and biochemical analyses were conducted to decode the metabolic shifts under NO stress by exposure to 0.3 mM SNAP in the presence or absence of 0.4 mM cPTIO. These findings revealed that the acclimation to NO stress comprises a temporally orchestrated implementation of metabolic processes: (1). modulation of NADPH oxidase (respiratory burst oxidase-like 2, RBOL2) and ROS signaling pathways for downstream mechanism regulation, (2). trigger of NO scavenging elements to reduce NO level; (3). prevention of photo-oxidative risk through photosynthesis inhibition and antioxidant defense system induction; (4). acclimation to nitrogen and sulfur shortage; (5). attenuation of transcriptional and translational activity together with degradation of damaged proteins through protein trafficking machinery (ubiquitin, SNARE, and autophagy) and molecular chaperone system for dynamic regulation of protein homeostasis. In addition, the expression of the gene encoding NADPH oxidase, RBOL2, showed a transient increase while that of RBOL1 was slightly decreased after NO challenge. It reflects that NADPH oxidase, a regulator in ROS-mediated signaling pathway, may be involved in the responses of Chlamydomonas to NO stress. In conclusion, our findings provide insight into the molecular events underlying acclimation mechanisms in Chlamydomonas to NO stress.

APA, Harvard, Vancouver, ISO, and other styles

38

Kolodny, Yuval, Yoav Avrahami, Hagit Zer, Miguel J. Frada, Yossi Paltiel, and Nir Keren. "Phycobilisome light-harvesting efficiency in natural populations of the marine cyanobacteria Synechococcus increases with depth." Communications Biology 5, no. 1 (July 22, 2022). http://dx.doi.org/10.1038/s42003-022-03677-2.

Full text

Abstract:

AbstractCyanobacteria of the genus Synechococcus play a key role as primary producers and drivers of the global carbon cycle in temperate and tropical oceans. Synechococcus use phycobilisomes as photosynthetic light-harvesting antennas. These contain phycoerythrin, a pigment-protein complex specialized for absorption of blue light, which penetrates deep into open ocean water. As light declines with depth, Synechococcus photo-acclimate by increasing both the density of photosynthetic membranes and the size of the phycobilisomes. This is achieved with the addition of phycoerythrin units, as demonstrated in laboratory studies. In this study, we probed Synechococcus populations in an oligotrophic water column habitat at increasing depths. We observed morphological changes and indications for an increase in phycobilin content with increasing depth, in summer stratified Synechococcus populations. Such an increase in antenna size is expected to come at the expense of decreased energy transfer efficiency through the antenna, since energy has a longer distance to travel. However, using fluorescence lifetime depth profile measurement approach, which is applied here for the first time, we found that light-harvesting quantum efficiency increased with depth in stratified water column. Calculated phycobilisome fluorescence quantum yields were 3.5% at 70 m and 0.7% at 130 m. Under these conditions, where heat dissipation is expected to be constant, lower fluorescence yields correspond to higher photochemical yields. During winter-mixing conditions, Synechococcus present an intermediate state of light harvesting, suggesting an acclimation of cells to the average light regime through the mixing depth (quantum yield of ~2%). Given this photo-acclimation strategy, the primary productivity attributed to marine Synechococcus should be reconsidered.

APA, Harvard, Vancouver, ISO, and other styles

39

Wyka, Tomasz P., Piotr Robakowski, Roma Żytkowiak, and Jacek Oleksyn. "Anatomical acclimation of mature leaves to increased irradiance in sycamore maple (Acer pseudoplatanus L.)." Photosynthesis Research, September 3, 2022. http://dx.doi.org/10.1007/s11120-022-00953-4.

Full text

Abstract:

AbstractTrees regenerating in the understory respond to increased availability of light caused by gap formation by undergoing a range of morphological and physiological adjustments. These adjustments include the production of thick, sun-type leaves containing thicker mesophyll and longer palisade cells than in shade-type leaves. We asked whether in the shade-regenerating tree Acer pseudoplatanus, the increase in leaf thickness and expansion of leaf tissues are possible also in leaves that are already fully formed, a response reported so far only for a handful of species. We acclimated potted seedlings to eight levels (from 1 to 100%) of solar irradiance and, in late summer, transferred a subset of them to full sunlight. Within 30 days, the pre-shaded leaves increased leaf mass per area and became thicker mostly due to the elongation of palisade cells, except for the most shaded individuals which suffered irreversible photo-oxidative damage. This anatomical acclimation was accompanied by a transient decline in photosynthetic efficiency of PSII (Fv/FM), the magnitude of which was related to the degree of pre-shading. The Fv/FM recovered substantially within the re-acclimation period. However, leaves of transferred plants were shed earlier in the fall, indicating that the acclimation was not fully effective. These results show that A. pseudoplatanus is one of the few known species in which mature leaves may re-acclimate anatomically to increased irradiance. This may be an important mechanism enhancing utilization of gaps created during the growing season.

APA, Harvard, Vancouver, ISO, and other styles

40

Wyka, Tomasz P., Piotr Robakowski, Roma Żytkowiak, and Jacek Oleksyn. "Anatomical adjustment of mature leaves of sycamore maple (Acer pseudoplatanus L.) to increased irradiance." Photosynthesis Research, January 16, 2022. http://dx.doi.org/10.1007/s11120-022-00898-8.

Full text

Abstract:

AbstractTrees regenerating in the understory respond to increased availability of light caused by gap formation by undergoing a range of morphological and physiological adjustments. These adjustments include the production of thick, sun-type leaves containing thicker mesophyll and longer palisade cells than in shade-type leaves. We asked whether in the shade-regenerating tree Acer pseudoplatanus, the increase in leaf thickness and expansion of leaf tissues are possible also in leaves that had been fully formed prior to the increase in irradiance, a response reported so far only for a handful of species. We acclimated potted seedlings to eight levels (from 1 to 100%) of solar irradiance and, in late summer, transferred a subset of them to full sunlight. Within 30 days, the shaded leaves increased leaf mass per area and became thicker mostly due to elongation of palisade cells, except for the most shaded individuals which suffered irreversible photo-oxidative damage. This anatomical acclimation was accompanied by partial degradation of chlorophyll and a transient decline in photosynthetic efficiency of PSII (Fv/FM). These effects were related to the degree of pre-shading. The Fv/FM recovered substantially within the re-acclimation period. However, leaves of transferred plants were shed significantly earlier in the fall, indicating that the acclimation was not fully effective. These results show that A. pseudoplatanus is one of the few known species in which mature leaves may re-acclimate anatomically to increased irradiance. This may be a potentially important mechanism enhancing utilization of gaps created during the growing season.

APA, Harvard, Vancouver, ISO, and other styles

41

Matsubara, Shizue, Trang Schneider, and Veronica G. Maurino. "Dissecting Long-Term Adjustments of Photoprotective and Photo-Oxidative Stress Acclimation Occurring in Dynamic Light Environments." Frontiers in Plant Science 7 (November 9, 2016). http://dx.doi.org/10.3389/fpls.2016.01690.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Moharekar, S., S. Moharekar, R. Tanaka, K. I. Ogawa, A. Tanaka, and T. Hara. "Great promoting effect of high irradiance from germination on flowering in Arabidopsis thaliana - a process of photo-acclimation." Photosynthetica 45, no. 2 (June 1, 2007). http://dx.doi.org/10.1007/s11099-007-0042-0.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Li, Jingjing, Yunlong Pang, Song Qin, Zhengyi Liu, Zhihai Zhong, Wanlin Song, and Longchuan Zhuang. "Comparison of the photo-acclimation potential of floating and benthic thalli of Sargassum horneri (Phaeophyta) during autumn and winter." Journal of Oceanology and Limnology, September 16, 2021. http://dx.doi.org/10.1007/s00343-021-0380-y.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Martinez, Stephane, Yuval Kolodny, Eli Shemesh, Federica Scucchia, Reinat Nevo, Smadar Levin-Zaidman, Yossi Paltiel, Nir Keren, Dan Tchernov, and Tali Mass. "Energy Sources of the Depth-Generalist Mixotrophic Coral Stylophora pistillata." Frontiers in Marine Science 7 (November 19, 2020). http://dx.doi.org/10.3389/fmars.2020.566663.

Full text

Abstract:

Energy sources of corals, ultimately sunlight and plankton availability, change dramatically from shallow to mesophotic (30–150 m) reefs. Depth-generalist corals, those that occupy both of these two distinct ecosystems, are adapted to cope with such extremely diverse conditions. In this study, we investigated the trophic strategy of the depth-generalist hermatypic coral Stylophora pistillata and the ability of mesophotic colonies to adapt to shallow reefs. We compared symbiont genera composition, photosynthetic traits and the holobiont trophic position and carbon sources, calculated from amino acids compound-specific stable isotope analysis (AA-CSIA), of shallow, mesophotic and translocated corals. This species harbors different Symbiodiniaceae genera at the two depths: Cladocopium goreaui (dominant in mesophotic colonies) and Symbiodinium microadriaticum (dominant in shallow colonies) with a limited change after transplantation. This allowed us to determine which traits stem from hosting different symbiont species compositions across the depth gradient. Calculation of holobiont trophic position based on amino acid δ15N revealed that heterotrophy represents the same portion of the total energy budget in both depths, in contrast to the dogma that predation is higher in corals growing in low light conditions. Photosynthesis is the major carbon source to corals growing at both depths, but the photosynthetic rate is higher in the shallow reef corals, implicating both higher energy consumption and higher predation rate in the shallow habitat. In the corals transplanted from deep to shallow reef, we observed extensive photo-acclimation by the Symbiodiniaceae cells, including substantial cellular morphological modifications, increased cellular chlorophyll a, lower antennae to photosystems ratios and carbon signature similar to the local shallow colonies. In contrast, non-photochemical quenching remains low and does not increase to cope with the high light regime of the shallow reef. Furthermore, host acclimation is much slower in these deep-to-shallow transplanted corals as evident from the lower trophic position and tissue density compared to the shallow-water corals, even after long-term transplantation (18 months). Our results suggest that while mesophotic reefs could serve as a potential refuge for shallow corals, the transition is complex, as even after a year and a half the acclimation is only partial.

APA, Harvard, Vancouver, ISO, and other styles

45

Muñoz, Paula, Alba Cotado, and Sergi Munné-Bosch. "Transient photoinhibition and photo-oxidative stress as an integral part of stress acclimation and plant development in a dioecious tree adapted to Mediterranean ecosystems." Tree Physiology, January 4, 2021. http://dx.doi.org/10.1093/treephys/tpaa177.

Full text

Abstract:

Abstract Mastic trees (Pistacia lentiscus L.) are dioecious perennial plants highly adapted to Mediterranean climates but display a high sensitivity to winter periods. In order to understand how sex, leaf phenology and ecological context could condition sensitivity to winter and associated mechanisms to acclimate to these conditions, photoinhibition and photo-oxidative stress markers were examined in mastic trees (Pistacia lentiscus L.) from a natural population growing in the Garraf Natural Park for a consecutive 12-month period (seasonal study), as well as in three populations naturally growing in the Montseny Natural Park, including the highest altitudes described for this species, during winter (altitudinal study). Results from these studies indicate that both the winter period and higher elevation influenced the degree of photoinhibition, but this was not conditioned by sex. In fact, winter photoinhibition occurred transiently even though it was accompanied by enhanced chlorophyll loss and malondialdehyde contents. Stress acclimation was achieved through biochemical adjustments in chloroplasts, characterized by anthocyanin shielding, increased de-epoxidation state of the xanthophyll cycle as well as tocopherol accumulation, and phenological adaptations, the latter allowing a complete resetting of the physiological performance of leaves. Moreover, although females showed higher lipid peroxidation than males during the coldest winter months, at the highest elevation and during flowering in spring, this oxidative stress was mild and transient with no negative consequences for the physiology of plants. It is concluded that evergreen mastic trees acclimate to winter conditions and higher elevations by activation of antioxidant defenses together with phenological adjustments, altogether playing a crucial role in plant survival. Sexual dimorphism in mastic trees appears as a relevant factor when considering sensitivity to photo-oxidative stress in winter and altitudinal conditions.

APA, Harvard, Vancouver, ISO, and other styles

46

Bernát, Gábor, Tomáš Zavřel, Eva Kotabová, László Kovács, Gábor Steinbach, Lajos Vörös, Ondřej Prášil, Boglárka Somogyi, and Viktor R. Tóth. "Photomorphogenesis in the Picocyanobacterium Cyanobium gracile Includes Increased Phycobilisome Abundance Under Blue Light, Phycobilisome Decoupling Under Near Far-Red Light, and Wavelength-Specific Photoprotective Strategies." Frontiers in Plant Science 12 (March 18, 2021). http://dx.doi.org/10.3389/fpls.2021.612302.

Full text

Abstract:

Photomorphogenesis is a process by which photosynthetic organisms perceive external light parameters, including light quality (color), and adjust cellular metabolism, growth rates and other parameters, in order to survive in a changing light environment. In this study we comprehensively explored the light color acclimation of Cyanobium gracile, a common cyanobacterium in turbid freshwater shallow lakes, using nine different monochromatic growth lights covering the whole visible spectrum from 435 to 687 nm. According to incident light wavelength, C. gracile cells performed great plasticity in terms of pigment composition, antenna size, and photosystem stoichiometry, to optimize their photosynthetic performance and to redox poise their intersystem electron transport chain. In spite of such compensatory strategies, C. gracile, like other cyanobacteria, uses blue and near far-red light less efficiently than orange or red light, which involves moderate growth rates, reduced cell volumes and lower electron transport rates. Unfavorable light conditions, where neither chlorophyll nor phycobilisomes absorb light sufficiently, are compensated by an enhanced antenna size. Increasing the wavelength of the growth light is accompanied by increasing photosystem II to photosystem I ratios, which involve better light utilization in the red spectral region. This is surprisingly accompanied by a partial excitonic antenna decoupling, which was the highest in the cells grown under 687 nm light. So far, a similar phenomenon is known to be induced only by strong light; here we demonstrate that under certain physiological conditions such decoupling is also possible to be induced by weak light. This suggests that suboptimal photosynthetic performance of the near far-red light grown C. gracile cells is due to a solid redox- and/or signal-imbalance, which leads to the activation of this short-term light acclimation process. Using a variety of photo-biophysical methods, we also demonstrate that under blue wavelengths, excessive light is quenched through orange carotenoid protein mediated non-photochemical quenching, whereas under orange/red wavelengths state transitions are involved in photoprotection.

APA, Harvard, Vancouver, ISO, and other styles

47

Jiang, Zong-Pei, Yuqi Tong, Mengmeng Tong, Jiajun Yuan, Qin Cao, and Yiwen Pan. "The Effects of Suspended Particulate Matter, Nutrient, and Salinity on the Growth of Amphidinium carterae Under Estuary Environmental Conditions." Frontiers in Marine Science 8 (July 12, 2021). http://dx.doi.org/10.3389/fmars.2021.690764.

Full text

Abstract:

The environmental conditions in estuaries display distinct variability along the river-ocean mixing continuum from turbid, eutrophic freshwater to clear, oligotrophic offshore oceanic water. In order to understand the effects of suspended particulate matter (SPM), nutrient, and salinity on phytoplankton growth, this study investigated the response of a harmful dinoflagellate (Amphidinium carterae Hulburt) to the ecological gradients in estuary environments. Rapid nutrient uptake and growth of A. carterae were detected in the nutrient-rich clear water, while nutrient concentration had little impact on the cellular chlorophyll a (Chl-a) content at the stationary phase. Light attenuation caused by SPM not only inhibited the specific growth rate of A. carterae but also prolonged its adaption period in turbid water, resulting in a delayed and weakened growth response. The elevated cellular Chl-a content under high SPM conditions resulting from photo-acclimation led to the decoupling of cell density and Chl-a concentration, indicating that Chl-a is not a reliable indicator for phytoplankton abundance in turbid environments. The combined effect of SPM and nutrient on specific growth rate of A. carterae can be explained by the comparative effect model, while the multiplicative effect model better predicted their interactive effect on the growth inhibitory rate (GIR). There is a transit of dominant limiting factor for phytoplankton growth along the salinity gradient in estuary environments. Salinity (for marine phytoplankton cannot survive under low salinity condition) and SPM are the dominant limiting factors at low salinities in nearshore turbid environments, while nutrient depletion exerts the dominant inhibitory effect in high salinity offshore water. Depending on the balance between enhancing nutrient limitation and reducing light limitation with increasing salinity, blooms most likely occur in the “optimal growth region” at intermediate salinities where light and nutrient are both suitable for phytoplankton growth.

APA, Harvard, Vancouver, ISO, and other styles

48

Celis-Plá, Paula S. M., José Luis Kappes, Félix L. Figueroa, Sandra V. Pereda, Karina Villegas, Robinson Altamirano, María Carmen Hernández-González, and Alejandro H. Buschmann. "Solar Radiation as an Isolated Environmental Factor in an Experimental Mesocosm Approach for Studying Photosynthetic Acclimation of Macrocystis pyrifera (Ochrophyta)." Frontiers in Plant Science 12 (July 2, 2021). http://dx.doi.org/10.3389/fpls.2021.622150.

Full text

Abstract:

Solar radiation effects on the ecophysiology and biochemical responses of the brown macroalga Macrocystis pyrifera (L.) C. Agardh were evaluated using a mesocosm approach in Southern Chile. Treatments with different radiation attenuations were simulated with three vertical attenuation coefficients: (1) total (Kd = 0.8 m−1), (2) attenuated (Kd = 1.2 m−1), and (3) low (Kd = 1.6 m−1) radiation levels. Nutrient concentration and temperature did not show differences under the three light conditions. Photosynthetic activity was estimated by in vivo chlorophyll a (Chla) fluorescence under the three light treatments as an isolated physical factor in both in situ solar radiation in the field. This was achieved using a pulse amplitude-modulated (PAM) fluorometera—Diving PAM (in situ). Photosynthetic activity and biochemical composition were measured in winter during two daily cycles (1DC and 2DC) in different parts of the thalli of the plant: (1) canopy zone, (2) middle zone, and (3) down zone, associated with different depths in the mesocosm system. Nevertheless, the in situ electron transport rate (ETRin situ) was higher in the exposed thalli of the canopy zone, independent of the light treatment conditions. The concentration of phenolic compounds (PC) increases in the down zone in the first daily cycle, and it was higher in the middle zone in the second daily cycle. The Chla increased in the morning time under total and attenuated radiation in the first daily cycle. Solar radiation increasing at midday prompted the photoinhibition of photosynthesis in the canopy zone but also an increase in productivity and phenol content. Therefore, light attenuation in the water column drove key differences in the photo-physiological responses of M. pyrifera, with the highest productivity occurring in thalli positioned in the canopy zone when exposed to solar irradiance.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Photo-acclimation'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles