scholarly journals The Effects of Cold Acclimation on Photosynthetic Apparatus and the Expression of COR14b in Four Genotypes of Barley (Hordeum vulgare) Contrasting in their Tolerance to Freezing and High-light Treatment in Cold Conditions

2008 ◽  
Vol 101 (5) ◽  
pp. 689-699 ◽  
Author(s):  
Marcin Rapacz ◽  
Barbara Wolanin ◽  
Katarzyna Hura ◽  
MirosŁaw Tyrka
Keyword(s):  
Hordeum Vulgare ◽  
Cold Acclimation ◽  
Photosynthetic Apparatus ◽  
Light Treatment ◽  
High Light ◽  
High Light Treatment

LHCII organization and thylakoid lipids affect the sensitivity of the photosynthetic apparatus to high-light treatment

2011 ◽  
Vol 49 (6) ◽  
pp. 629-635 ◽  
Author(s):  
Kolyo G. Dankov ◽  
Anelia G. Dobrikova ◽  
Bettina Ughy ◽  
Balázs Bogos ◽  
Zoltan Gombos ◽  
...  
Keyword(s):  
Photosynthetic Apparatus ◽  
Light Treatment ◽  
High Light ◽  
High Light Treatment ◽  
Thylakoid Lipids

Fluorescence as a tool in photosynthesis research: application in studies of photoinhibition, cold acclimation and freezing stress

1989 ◽  
Vol 323 (1216) ◽  
pp. 281-293 ◽  
Keyword(s):  
Quantum Yield ◽  
Cold Acclimation ◽  
Spinacia Oleracea ◽  
Photosynthetic Apparatus ◽  
Fluorescence Induction ◽  
High Light ◽  
Thermal Dissipation ◽  
Freezing Stress ◽  
Chlorophyll Fluorescence Induction ◽  
Freezing And Thawing

Chlorophyll fluorescence induction (at 20 °C and 77 K) and quenching were analysed in relation to effects of environmental stresses imposed by chilling in high light and by freezing and thawing of spinach ( Spinacia oleracea L.) leaves. The data indicate that cold acclimation of spinach plants, which leads to increased frost tolerance of the leaves, results in decreased susceptibility to photoinhibition of photosynthesis at chilling temperatures. When plants acclimated to 18 °C and 260-300 µmol quanta m -2 s -1 were exposed to higher light (550 µmol quanta m -2 s -1 ) at 4 °C, they developed strong photoinhibition, as characterized by decreased quantum yield of O 2 evolution and decreased ratio of variable: maximum fluorescence (F V /F M ) of photosystem II. The decrease in F V /F M resulted from a decline in F V and an increase in F 0 . The F V /F M ratio was lowered to a significantly greater extent when induction was recorded at 20 °C, as compared with 77 K. The effects related to photoinhibition were fully reversible at 18 °C in dim light. Plants that had been cold-acclimated for 10 days exhibited slightly decreased quantum yield and lowered F V /F M ratio. However, they did not show further photoinhibition on exposure to 550 µmol quanta m -2 s -1 at 4 °C. The reversible photoinhibition is discussed as a protective pathway serving for thermal dissipation of excessive light energy. It is hypothesized that such a mechanism prevents destruction of the photosynthetic apparatus, until other means of protection become effective during long-term acclimation to high light. Inhibition of photosynthetic carbon assimilation caused by freezing and thawing of leaves in the dark was closely correlated with inhibition of photochemical fluorescence quenching (q Q ). As a sensitive response of the thylakoid membranes to freezing stress, the energy-dependent quenching, q E , was inhibited. Only more severe impact of freezing caused a significant decline in the F V /F M ratio. It is concluded that measurements of fluorescence induction signals ( F V /F M ratios) provide a sensitive tool with which to investigate photoinhibition, whereas freezing damage to the photosynthetic system can be detected more readily by the quenching coefficients q Q and q E than by F V /F M ratios.

Wood Density and Above-Ground Growth in High and Low Wood Density Clones of Pinus radiata D. Don

1990 ◽  
Vol 17 (6) ◽  
pp. 615 ◽  
Author(s):  
DW Sheriff ◽  
DA Rook
Keyword(s):  
Wood Density ◽  
Pinus Radiata ◽  
Light Treatment ◽  
High Light ◽  
The Other ◽  
Stem Volume ◽  
Carbon Gain ◽  
Simple Relationship ◽  
Ground Biomass ◽  
High Light Treatment

In Pinus radiata a negative relationship has usually been found between stem volume and wood density. Clones previously found to produce wood of high or low density were used to investigate interrelationships between above-ground partitioning coefficients, carbon gain, and wood density. Cuttings had been propagated c. 5 years earlier, and were 5 m high when the experiment started. Potential carbon gain of the tree was manipulated by using two light environments; one with a light level c. 1.5 times the other. Measurements were of changes in stem, branch, and needle biomass during the 305-day experiment, of rates of photosynthesis, and of wood density by β-ray densitometry and microscopy; densities determined by the two techniques were the same. For all but two trees, wood densities of a stem and its branches were the same; for the other two, stem density was 13% less than that of their branches. Trees in the high light treatment accumulated more above-ground biomass, but there was no simple relationship between wood density and either above-ground growth or photosynthesis. With one exception, partitioning of photosynthate to stem was constant. In most cases, proportionately less photosynthate (30-80%) was allocated to below-ground biomass in the low light treatment than in the high light treatment (60-80%).

scholarly journals Selective Photobleaching of Chlorophylls and Carotenoids in Photosystem I Particles under High-Light Treatment

2007 ◽  
Vol 83 (6) ◽  
pp. 1301-1307 ◽  
Author(s):  
Atanaska Andreeva ◽  
Silvia Abarova ◽  
Katerina Stoitchkova ◽  
Rafael Picorel ◽  
Maya Velitchkova
Keyword(s):  
Photosystem I ◽  
Light Treatment ◽  
High Light ◽  
High Light Treatment

scholarly journals Identification of Small RNAs During High Light Acclimation in Arabidopsis thaliana

2021 ◽  
Vol 12 ◽  
Author(s):  
Bhavika Tiwari ◽  
Kristin Habermann ◽  
M. Asif Arif ◽  
Oguz Top ◽  
Wolfgang Frank
Keyword(s):  
Small Rnas ◽  
Regulation Of Gene Expression ◽  
Biological Significance ◽  
Light Treatment ◽  
High Light ◽  
Light Acclimation ◽  
Light Conditions ◽  
Gene Pairs ◽  
High Light Treatment ◽  
Non Coding Rnas

The biological significance of non-coding RNAs (ncRNAs) has been firmly established to be important for the regulation of genes involved in stress acclimation. Light plays an important role for the growth of plants providing the energy for photosynthesis; however, excessive light conditions can also cause substantial defects. Small RNAs (sRNAs) are a class of non-coding RNAs that regulate transcript levels of protein-coding genes and mediate epigenetic silencing. Next generation sequencing facilitates the identification of small non-coding RNA classes such as miRNAs (microRNAs) and small-interfering RNAs (siRNAs), and long non-coding RNAs (lncRNAs), but changes in the ncRNA transcriptome in response to high light are poorly understood. We subjected Arabidopsis plants to high light conditions and performed a temporal in-depth study of the transcriptome data after 3 h, 6 h, and 2 days of high light treatment. We identified a large number of high light responsive miRNAs and sRNAs derived from NAT gene pairs, lncRNAs and TAS transcripts. We performed target predictions for differentially expressed miRNAs and correlated their expression levels through mRNA sequencing data. GO analysis of the targets revealed an overrepresentation of genes involved in transcriptional regulation. In A. thaliana, sRNA-mediated regulation of gene expression in response to high light treatment is mainly carried out by miRNAs and sRNAs derived from NAT gene pairs, and from lncRNAs. This study provides a deeper understanding of sRNA-dependent regulatory networks in high light acclimation.

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.

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