Influence of light intensity and salt-treatment on mode of photosynthesis and enzymes of the antioxidative response system of Mesembryanthemum crystallinum

2002 ◽  
Vol 29 (1) ◽  
pp. 13 ◽  
Author(s):  
Fernando Broetto ◽  
Ulrich Lüttge ◽  
Rafael Ratajczak
Keyword(s):  
Light Stress ◽  
High Light ◽  
Mesembryanthemum Crystallinum ◽  
Stress Factors ◽  
Lag Phase ◽  
Light Conditions ◽  
Cam Plants ◽  
Salt Treatment ◽  
Sod Activity ◽  
Antioxidative Response

The metabolic switch from C3-photosynthesis to crassulacean acid metabolism (CAM),and the antioxidative response of Mesembryanthemum crystallinum L. plants cultured under severe salt stress and high light intensities, and a combination of both stress conditions, were studied. High light conditions led to a more rapid CAM induction than salinity. The induction time was still shortened when both stress factors were combined. A main pattern observed in CAM plants was a decrease in mitochondrial Mn–superoxide dismutase (SOD) activity during the day. The activities of the chloroplastic Fe–SOD and cytosolic CuZn–SOD were increased due to salt treatment after a lag phase, while catalase activity was decreased. Combination of salt and light stress did not lead to a higher SOD activity as found after application of one stress factor alone, indicating that there is a threshold level of the oxidative stress response. The fact that salt-stressed plants grown under high light conditions showed permanent photoinhibition and lost the ability for nocturnal malate storage after 9 d of treatment indicate serious malfunction of metabolism, leading to accelerated senescence. Comparison of CuZn–SOD activity with CuZn–SOD protein amount, which was determined immunologically, indicates that the activity of the enzyme is at least partially post-translationally regulated.

scholarly journals Occurrence of neoxanthin and lutein epoxide cycle in parasitic Cuscuta species.

2008 ◽  
Vol 55 (1) ◽  
pp. 183-190 ◽  
Author(s):  
Jerzy Kruk ◽  
Renata Szymańska
Keyword(s):  
Substrate Specificity ◽  
Xanthophyll Cycle ◽  
Higher Plants ◽  
Light Stress ◽  
High Light ◽  
Light Conditions ◽  
Strong Light ◽  
Zeaxanthin Epoxidase ◽  
Typical Response ◽  
Cuscuta Species

In the present study, xanthophyll composition of eight parasitic Cuscuta species under different light conditions was investigated. Neoxanthin was not detected in four of the eight species examined, while in others it occurred at the level of several percent of total xanthophylls. In C. gronovii and C. lupuliformis it was additionally found that the neoxanthin content was considerably stimulated by strong light. In dark-adapted plants, lutein epoxide level amounted to 10-22% of total xanthophylls in only three species, the highest being for C. lupuliformis, while in others it was below 3%, indicating that the lutein epoxide cycle is limited to only certain Cuscuta species. The obtained data also indicate that the presence of the lutein epoxide cycle and of neoxanthin is independent and variable among the Cuscuta species. The xanthophyll cycle carotenoids violaxanthin, antheraxanthin and zeaxanthin were identified in all the examined species and occurred at the level found in other higher plants. The xanthophyll and lutein epoxide cycle pigments showed typical response to high light stress. The obtained results also suggest that the ability of higher plants to synthesize lutein epoxide probably does not depend on the substrate specificity of zeaxanthin epoxidase but on the availability of lutein for the enzyme.

Salt-induced accumulation of glycine betaine is inhibited by high light in durum wheat

2011 ◽  
Vol 38 (2) ◽  
pp. 139 ◽  
Author(s):  
Petronia Carillo ◽  
Danila Parisi ◽  
Pasqualina Woodrow ◽  
Giovanni Pontecorvo ◽  
Giuseppina Massaro ◽  
...  
Keyword(s):  
Amino Acids ◽  
Durum Wheat ◽  
Glycine Betaine ◽  
High Light ◽  
Light Conditions ◽  
Salt Treatment ◽  
Wheat Seedlings ◽  
Triticum Durum Desf ◽  
Tyrosine Content

In this study, we determined the effects of both salinity and high light on the metabolism of durum wheat (Triticum durum Desf. cv. Ofanto) seedlings, with a special emphasis on the potential role of glycine betaine in their protection. Unexpectedly, it appears that high light treatment inhibits the synthesis of glycine betaine, even in the presence of salt stress. Additional solutes such as sugars and especially amino acids could partially compensate for the decrease in its synthesis upon exposure to high light levels. In particular, tyrosine content was strongly increased by high light, this effect being enhanced by salt treatment. Interestingly, a large range of well-known detoxifying molecules were also not induced by salt treatment in high light conditions. Taken together, our results question the role of glycine betaine in salinity tolerance under light conditions close to those encountered by durum wheat seedlings in their natural environment and suggest the importance of other mechanisms, such as the accumulation of minor amino acids.

scholarly journals Genome-Wide Identification and Expression Analyses of the Fibrillin Family Genes Reveal Their Involvement in the Photoprotection in Cucumber

2018 ◽  
Author(s):  
Inyoung Kim ◽  
Sang-Choon Lee ◽  
Eun-Ha Kim ◽  
Kiwhan Song ◽  
Tae-Jin Yang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Dna Sequences ◽  
Light Stress ◽  
High Light ◽  
Light Conditions ◽  
Transcript Levels ◽  
Photosynthetic Organisms ◽  
Conserved Domain ◽  
Genome Wide ◽  
Cucumber Genome

Fibrillin (FBN) is a plastid lipid-associated protein found in photosynthetic organisms from cyanobacteria to plants. In this study, 10 CsaFBN genes were identified in genomic DNA sequences of cucumber (Chinese long and Gy14) through database searches using the conserved domain of FBN and the 14 FBN genes of Arabidopsis. Phylogenetic analysis of CsaFBN protein sequences showed that there was no counterpart of Arabidopsis and rice FBN5 in the cucumber genome. FBN5 is essential for growth in Arabidopsis and rice; its absence in cucumber may be because of incomplete genome sequences or that another FBN carries out its functions. Among the 10 CsaFBN genes, CsaFBN1 and CsaFBN9 were the most divergent in terms of nucleotide sequences. Most of the CsaFBN genes were expressed in the leaf, stem, and fruit. CsaFBN4 showed the highest mRNA expression levels in various tissues, followed by CsaFBN6, CsaFBN1, and CsaFBN9. High-light stress combined with low temperature decreased photosynthetic efficiency and highly induced transcript levels of CsaFBN1, CsaFBN6, and CsaFBN11, which decreased after 24 h treatment. Transcript levels of the other seven genes were changed only slightly. This result suggests that CsaFBN1, CsaFBN6, and CsaFBN11 may be involved in photoprotection under high-light conditions at low temperature.

scholarly journals Defoliation Significantly Suppressed Plant Growth Under Low Light Conditions in Two Leguminosae Species

2022 ◽  
Vol 12 ◽  
Author(s):  
Ning Wang ◽  
Tianyu Ji ◽  
Xiao Liu ◽  
Qiang Li ◽  
Kulihong Sairebieli ◽  
...  
Keyword(s):  
Plant Growth ◽  
Combined Treatment ◽  
Chlorophyll Concentration ◽  
Light Stress ◽  
Early Period ◽  
Light Treatment ◽  
High Light ◽  
Herbivorous Insects ◽  
Light Conditions ◽  
Low Light

Seedlings in regenerating layer are frequently attacked by herbivorous insects, while the combined effects of defoliation and shading are not fully understood. In the present study, two Leguminosae species (Robinia pseudoacacia and Amorpha fruticosa) were selected to study their responses to combined light and defoliation treatments. In a greenhouse experiment, light treatments (L+, 88% vs L−, 8% full sunlight) and defoliation treatments (CK, without defoliation vs DE, defoliation 50% of the upper crown) were applied at the same time. The seedlings’ physiological and growth traits were determined at 1, 10, 30, and 70 days after the combined treatment. Our results showed that the effects of defoliation on growth and carbon allocation under high light treatments in both species were mainly concentrated in the early stage (days 1–10). R. pseudoacacia can achieve growth recovery within 10 days after defoliation, while A. fruticosa needs 30 days. Seedlings increased SLA and total chlorophyll concentration to improve light capture efficiency under low light treatments in both species, at the expense of reduced leaf thickness and leaf lignin concentration. The negative effects of defoliation treatment on plant growth and non-structural carbohydrates (NSCs) concentration in low light treatment were significantly higher than that in high light treatment after recovery for 70 days in R. pseudoacacia, suggesting sufficient production of carbohydrate would be crucial for seedling growth after defoliation. Plant growth was more sensitive to defoliation and low light stress than photosynthesis, resulting in NSCs accumulating during the early period of treatment. These results illustrated that although seedlings could adjust their resource allocation strategy and carbon dynamics in response to combined defoliation and light treatments, individuals grown in low light conditions will be more suppressed by defoliation. Our results indicate that we should pay more attention to understory seedlings’ regeneration under the pressure of herbivorous insects.

scholarly journals Color-Specific Recovery to Extreme High-Light Stress in Plants

Life ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 812
Author(s):  
Débora Parrine ◽  
Todd M. Greco ◽  
Bilal Muhammad ◽  
Bo-Sen Wu ◽  
Xin Zhao ◽  
...  
Keyword(s):  
Blue Light ◽  
Light Stress ◽  
Red Light ◽  
Light Treatment ◽  
High Light ◽  
Mrna Levels ◽  
Light Conditions ◽  
High Light Stress ◽  
General Response ◽  
The Impact

Plants pigments, such as chlorophyll and carotenoids, absorb light within specific wavelength ranges, impacting their response to environmental light changes. Although the color-specific response of plants to natural levels of light is well described, extreme high-light stress is still being discussed as a general response, without considering the impact of wavelengths in particular response processes. In this study, we explored how the plant proteome coordinated the response and recovery to extreme light conditions (21,000 µmol m−2 s−1) under different wavelengths. Changes at the protein and mRNA levels were measured, together with the photosynthetic parameters of plants under extreme high-light conditions. The changes in abundance of four proteins involved in photoinhibition, and in the biosynthesis/assembly of PSII (PsbS, PsbH, PsbR, and Psb28) in both light treatments were measured. The blue-light treatment presented a three-fold higher non-photochemical quenching and did not change the level of the oxygen-evolving complex (OEC) or the photosystem II (PSII) complex components when compared to the control, but significantly increased psbS transcripts. The red-light treatment caused a higher abundance of PSII and OEC proteins but kept the level of psbS transcripts the same as the control. Interestingly, the blue light stimulated a more efficient energy dissipation mechanism when compared to the red light. In addition, extreme high-light stress mechanisms activated by blue light involve the role of OEC through increasing PsbS transcript levels. In the proteomics spatial analysis, we report disparate activation of multiple stress pathways under three differently damaged zones as the enriched function of light stress only found in the medium-damaged zone of the red LED treatment. The results indicate that the impact of extreme high-light stress on the proteomic level is wavelength-dependent.

scholarly journals Light-Dependent Oxidative Stress Determines Physiological Leaf Spot Formation in Barley

2004 ◽  
Vol 94 (6) ◽  
pp. 584-592 ◽  
Author(s):  
Yue-Xuan Wu ◽  
Andreas von Tiedemann
Keyword(s):  
Oxidative Stress ◽  
Leaf Spot ◽  
Spring Barley ◽  
Light Stress ◽  
Field Conditions ◽  
Stress Factors ◽  
Monodehydroascorbate Reductase ◽  
Sod Activity ◽  
Active Radiation ◽  
Ros Metabolism

We reported previously that physiological leaf spot (PLS) formation in winter and spring barley is dependent on genotype-related oxidative stress under field conditions. In the present study, we searched for factors inducing PLS symptoms in the greenhouse similar to those observed in the field and investigated its relationship to reactive oxygen species (ROS) metabolism. We found that in the greenhouse, oxidative stress induced spring barley cv. Extract, which is sensitive to PLS, to express symptoms similar to those observed in the field. Leaves severely affected by PLS showed significantly lower activities of key enzymes in the Halliwell-Asada cycle such as ascorbate peroxidase, glutathione reductase, dehy-droascorbate reductase, and monodehydroascorbate reductase. The sensitive cultivar also showed lower levels of total superoxide dismutase (SOD) and Cu/Zn-SOD activity but a higher level of chloroplast-specific Fe-SOD activity than that of the insensitive cultivar. Thus, an unbalanced ROS metabolism in chloroplasts may trigger PLS incidence in sensitive cultivars, which is in agreement with the fact that light is essential for the induction of PLS expression under both field and greenhouse conditions. Accordingly, under greenhouse conditions, continuous light stress (7 days), but not light shock treatments, induced PLS similar to that of field conditions in sensitive cv. Extract, but not in resistant cv. Scarlett. Light with a high proportion of energy in the blue wavelength spectrum (350 to 560 nm) was significantly more PLS inductive than light with a pronounced red (photosynthetically active radiation) spectrum (580 to 650 nm). Exposure to ozone did not produce PLS-like symptoms. Furthermore, similar to earlier observations in the field, PLS symptom expression was closely correlated with the accumulation of superoxide (O2 •-) detected by both biochemical and histochemical assays. Taken together, these data suggest that PLS in barley is genotype-dependent but its expression appears to be induced by certain environmental stress factors, among which photosyn-thetically active radiation plays a major role.

scholarly journals Mutations in hik26 and slr1916 lead to high-light stress tolerance in Synechocystis sp. PCC6803

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Katsunori Yoshikawa ◽  
Kenichi Ogawa ◽  
Yoshihiro Toya ◽  
Seiji Akimoto ◽  
Fumio Matsuda ◽  
...  
Keyword(s):  
Stress Tolerance ◽  
Parental Strain ◽  
Energy Flow ◽  
Light Stress ◽  
High Light ◽  
Whole Genome Sequence ◽  
Light Conditions ◽  
Adaptive Laboratory Evolution ◽  
High Light Stress ◽  
Desirable Feature

AbstractIncreased tolerance to light stress in cyanobacteria is a desirable feature for their applications. Here, we obtained a high light tolerant (Tol) strain of Synechocystis sp. PCC6803 through an adaptive laboratory evolution, in which the cells were repeatedly sub-cultured for 52 days under high light stress conditions (7000 to 9000 μmol m−2 s−1). Although the growth of the parental strain almost stopped when exposed to 9000 μmol m−2 s−1, no growth inhibition was observed in the Tol strain. Excitation-energy flow was affected because of photosystem II damage in the parental strain under high light conditions, whereas the damage was alleviated and normal energy flow was maintained in the Tol strain. The transcriptome data indicated an increase in isiA expression in the Tol strain under high light conditions. Whole genome sequence analysis and reverse engineering revealed two mutations in hik26 and slr1916 involved in high light stress tolerance in the Tol strain.

scholarly journals Alterations in leaf photosynthetic electron transport in Welsh onion (Allium fistulosum L.) under different light intensity and soil water conditions

2019 ◽  
Author(s):  
Xuena Liu ◽  
Song Gao ◽  
Ying Liu ◽  
Kun Xu
Keyword(s):  
Drought Stress ◽  
Electron Transport ◽  
Light Stress ◽  
Photosynthetic Electron Transport ◽  
High Light ◽  
Stress Factors ◽  
Welsh Onion ◽  
Drought Treatment ◽  
Ojip Transient ◽  
Strong Light

Abstract Background: Welsh onions are often affected by stressful environments, such as high light and drought, during summer cultivation, which hinders their growth. To date, few studies have focused on leaf photosynthesis of Welsh onions during summer. We used carbon dioxide assimilation and OJIP transient and MR curves to analyze the photosynthetic characteristics of Welsh onions. Results: The results showed that strong light and drought could lead to a decrease in leaf pigment content. Simple high light stress caused a decrease in the net photosynthetic rate through stomatal limitation, while the simple drought treatment and the two stress factors combined caused a nonstomatal limitation. PSII energy distribution indicated that strong light and drought stress reduced the photochemical quantum efficiency of PSII. OJIP curve analysis showed that FO and FJ were increased, Fm was decreased, and a distinct K-phase was induced. In addition, OJIP parameters, including RC/CSO, TRO/ABS, ETO/TRO, and PIABS, were significantly reduced. MR analysis showed that strong light and drought stress blocked MR transients, leading to a gradual decrease in VPSI and VPSII-PSI. Conclusions: In general, the photosynthesis of Welsh onion was inhibited by high light and drought, which destroyed the receptor and donor side of PSII and reduced the electron transport capacity of PSII and PSI.

scholarly journals ACCLIMATION OF PHOTOSYNTHESIS TO THE ENVIRONMENT 1 regulates Photosystem II Supercomplex dynamics in response to light in Chlamydomonas reinhardtii

2020 ◽  
Author(s):  
Marie Chazaux ◽  
Stefano Caffarri ◽  
Juliane Da Graça ◽  
Stephan Cuiné ◽  
Magali Floriani ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Chlamydomonas Reinhardtii ◽  
Light Stress ◽  
High Light ◽  
Light Acclimation ◽  
Light Conditions ◽  
Core Complex ◽  
Photosynthetic Organisms ◽  
Thylakoid Protein ◽  
Thylakoid Stacking

AbstractPhotosynthetic organisms require acclimation mechanisms to regulate photosynthesis in response to light conditions. Here, two mutant alleles of ACCLIMATION OF PHOTOSYNTHESIS TO THE ENVIRONMENT 1 (ape1) have been characterized in Chlamydomonas reinhardtii. The ape1 mutants are photosensitive and show PSII photoinhibition during high light acclimation or under high light stress. The ape1 mutants retain more PSII super-complexes and have changes to thylakoid stacking relative to control strains during photosynthetic growth at different light intensities. The APE1 protein is found in all oxygenic phototrophs and encodes a 25 kDa thylakoid protein that interacts with the Photosystem II core complex as monomers, dimers and supercomplexes. We propose a model where APE1 bound to PSII supercomplexes releases core complexes and promotes PSII heterogeneity influencing the stacking of Chlamydomonas thylakoids. APE1 is a regulator in light acclimation and its function is to reduce over-excitation of PSII centres and avoid PSII photoinhibition to increase the resilience of photosynthesis to high light.

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