Special senescence stages in chloroplast ultrastructure of radish seedlings induced by the photosystem II-herbicide bentazon

PROTOPLASMA ◽  
1982 ◽  
Vol 110 (2) ◽  
pp. 138-142 ◽  
Author(s):  
D. Meier ◽  
H. K. Lichtenthaler
Keyword(s):  
Photosystem Ii ◽  
Chloroplast Ultrastructure ◽  
Radish Seedlings

Change of Chloroplast Ultrastructure in Radish Seedlings under the Influence of the Photosystem II-Herbicide Bentazon

1980 ◽  
Vol 35 (7-8) ◽  
pp. 656-664 ◽  
Author(s):  
D. Meier ◽  
H. K. Lichtenthaler ◽  
G. Burkard
Keyword(s):  
Photosystem Ii ◽  
Raphanus Sativus ◽  
Photosynthetic Apparatus ◽  
Chloroplast Ultrastructure ◽  
Raphanus Sativus L ◽  
Radish Seedlings

The influence of the photosystem II-herbicide bentazon on the ultrastructure of chloroplasts of radish seedlings (Raphanus sativus L.) was investigated with special emphasis on thylakoid development and grana formation. Bentazon application (10-3 ᴍ) induces the formation of broader and higher grana stacks (grana width: 0.5-0.6 μm; greatest frequency: 3-8 thylakoids per granum) than in the control plants (grana width: 0.3 μm; greatest frequency: 2-4 thylakoids per granum). Furthermore, the amount of chloroplast lamellae is enhanced, as are the stacking degree of thylakoids and the grana area. The chloroplasts of bentazon-treated plants appear to be shorter and thicker than in the controls and show all signs of a shade-type adaptation of the photosynthetic apparatus.

scholarly journals Excess Zinc Supply Reduces Cadmium Uptake and Mitigates Cadmium Toxicity Effects on Chloroplast Structure, Oxidative Stress, and Photosystem II Photochemical Efficiency in Salvia sclarea Plants

Toxics ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 36
Author(s):  
Ilektra Sperdouli ◽  
Ioannis-Dimosthenis S. Adamakis ◽  
Anelia Dobrikova ◽  
Emilia Apostolova ◽  
Anetta Hanć ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Photosystem Ii ◽  
Adverse Effects ◽  
Cadmium Toxicity ◽  
Photochemical Efficiency ◽  
Antimicrobial Properties ◽  
Chloroplast Ultrastructure ◽  
Salvia Sclarea ◽  
Psii Photochemistry ◽  
Hoagland Nutrient Solution

Salvia sclarea L. is a Cd2+ tolerant medicinal herb with antifungal and antimicrobial properties cultivated for its pharmacological properties. However, accumulation of high Cd2+ content in its tissues increases the adverse health effects of Cd2+ in humans. Therefore, there is a serious demand to lower human Cd2+ intake. The purpose of our study was to evaluate the mitigative role of excess Zn2+ supply to Cd2+ uptake/translocation and toxicity in clary sage. Salvia plants were treated with excess Cd2+ (100 μM CdSO4) alone, and in combination with Zn2+ (900 μM ZnSO4), in modified Hoagland nutrient solution. The results demonstrate that S. sclarea plants exposed to Cd2+ toxicity accumulated a significant amount of Cd2+ in their tissues, with higher concentrations in roots than in leaves. Cadmium exposure enhanced total Zn2+ uptake but also decreased its translocation to leaves. The accumulated Cd2+ led to a substantial decrease in photosystem II (PSII) photochemistry and disrupted the chloroplast ultrastructure, which coincided with an increased lipid peroxidation. Zinc application decreased Cd2+ uptake and translocation to leaves, while it mitigated oxidative stress, restoring chloroplast ultrastructure. Excess Zn2+ ameliorated the adverse effects of Cd2+ on PSII photochemistry, increasing the fraction of energy used for photochemistry (ΦPSII) and restoring PSII redox state and maximum PSII efficiency (Fv/Fm), while decreasing excess excitation energy at PSII (EXC). We conclude that excess Zn2+ application eliminated the adverse effects of Cd2+ toxicity, reducing Cd2+ uptake and translocation and restoring chloroplast ultrastructure and PSII photochemical efficiency. Thus, excess Zn2+ application can be used as an important method for low Cd2+-accumulating crops, limiting Cd2+ entry into the food chain.

scholarly journals Chloroplast ultrastructure regeneration with protection of photosystem II is responsible for the functional ‘stay-green’ trait in wheat

2012 ◽  
Vol 36 (3) ◽  
pp. 683-696 ◽  
Author(s):  
P. G. LUO ◽  
K. J. DENG ◽  
X. Y. HU ◽  
L. Q. LI ◽  
X. LI ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Chloroplast Ultrastructure ◽  
Stay Green

Herbicides which Inhibit Electron Transport or Produce Chlorosis and Their Effect on Chloroplast Development in Radish Seedlings I. Chlorophyll a Fluorescence Transients and Photosystem II Activity

1982 ◽  
Vol 37 (3-4) ◽  
pp. 268-275 ◽  
Author(s):  
K. H. Grumbach
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Chlorophyll A ◽  
Oxygen Evolution ◽  
Chlorophyll A Fluorescence ◽  
Photosynthetic Electron Transport ◽  
Photosystem Ii Activity ◽  
Chlorophyll A Fluorescence Transients ◽  
Radish Seedlings ◽  
Fluorescence Transients

Abstract Diuron and bentazon are very strong inhibitors of the photosynthetic electron transport in isolated radish chloroplasts. The chlorosis producing herbicide SAN 6706 also inhibited the photosystem II dependent oxygen evolution. Aminotriazole had no effect. The inhibitor concentration for 50% inhibition of photosystem II activity was 10-7 m for diuron and 10-4 m for bentazon and SAN 6706 respectively.Diuron and bentazon quenched the chlorophyll a fluorescence transients in isolated radish chloroplasts drastically, while aminotriazole was not effective. It was of particular interest that the bleaching herbicide SAN 6706 inhibited photosystem II dependent oxygen evolution in a similar concentration as bentazon but had no effect on the chlorophyll a-fluorescence transients suggesting that SAN 6706 is not binding to the same site of the electron transport chain as diuron and bentazon.Apart from their direct influence on electron transport in isolated photosynthetically active chloroplasts the photosystem II and bleaching herbicides assayed also strongly affected photosynthesis in radish seedlings that were grown in the presence of the herbicides for a long time. As already obtained using isolated chloroplasts, photosystem II dependent oxygen evolution like the chlorophyll a fluorescence transients were strongly inhibited by the photosystem II herbicides diuron and bentazon. A reduction but no inhibition of photosystem II activity was observed in plants that were grown in the presence of aminotriazole. The pyridazinone SAN 6706 was behaving contradictory. In partly green plants photosystem II activity was still maintained and even higher than in untreated plants while in albinistic plants no photosynthetic activity was detected.

Linking sensitivity of photosystem II to UV-B with chloroplast ultrastructure and UV-B absorbing pigments contents in A. thaliana L. phyAphyB double mutants

2020 ◽  
Vol 91 (1) ◽  
pp. 13-21 ◽  
Author(s):  
Vladimir D. Kreslavski ◽  
Xin Huang ◽  
Galina Semenova ◽  
Alexandra Khudyakova ◽  
Galina Shirshikova ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Chloroplast Ultrastructure

High temperature reduces photosynthesis in maize leaves by damaging chloroplast ultrastructure and photosystem II

2020 ◽  
Vol 206 (5) ◽  
pp. 548-564 ◽  
Author(s):  
Yu‐Ting Li ◽  
Wei‐Wei Xu ◽  
Bai‐Zhao Ren ◽  
Bin Zhao ◽  
Jiwang Zhang ◽  
...  
Keyword(s):  
High Temperature ◽  
Photosystem Ii ◽  
Chloroplast Ultrastructure ◽  
Maize Leaves

scholarly journals Physiological and Transcriptomic Analysis Reveals the Responses and Difference to High Temperature and Humidity Stress in Two Melon Genotypes

2022 ◽  
Vol 23 (2) ◽  
pp. 734
Author(s):  
Jinyang Weng ◽  
Asad Rehman ◽  
Pengli Li ◽  
Liying Chang ◽  
Yidong Zhang ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
High Temperature ◽  
Photosystem Ii ◽  
Photosystem I ◽  
Chloroplast Ultrastructure ◽  
Future Research ◽  
Leaf Water Content ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters ◽  
Temperature And Humidity

Due to the frequent occurrence of continuous high temperatures and heavy rain in summer, extremely high-temperature and high-humidity environments occur, which seriously harms crop growth. High temperature and humidity (HTH) stress have become the main environmental factors of combined stress in summer. The responses of morphological indexes, physiological and biochemical indexes, gas exchange parameters, and chlorophyll fluorescence parameters were measured and combined with chloroplast ultrastructure and transcriptome sequencing to analyze the reasons for the difference in tolerance to HTH stress in HTH-sensitive ‘JIN TAI LANG’ and HTH-tolerant ‘JIN DI’ varieties. The results showed that with the extension of stress time, the superoxide dismutase (SOD), peroxidase (POD), and ascorbate peroxidase (APX) activities of the two melon varieties increased rapidly, the leaf water content increased, and the tolerant varieties showed stronger antioxidant capacity. Among the sensitive cultivars, Pn, Fv/Fm, photosystem II, and photosystem I chlorophyll fluorescence parameters were severely inhibited and decreased rapidly with the extension of stress time, while the HTH-tolerant cultivars slightly decreased. The cell membrane and chloroplast damage in sensitive cultivars were more severe, and Lhca1, Lhca3, and Lhca4 proteins in photosystem II and Lhcb1-Lhcb6 proteins in photosystem I were inhibited compared with those in the tolerant cultivar. These conclusions may be the main reason for the different tolerances of the two cultivars. These findings will provide new insights into the response of other crops to HTH stress and also provide a basis for future research on the mechanism of HTH resistance in melon.

scholarly journals Direct energy transfer from photosystem II to photosystem I confers winter sustainability in Scots Pine

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Pushan Bag ◽  
Volha Chukhutsina ◽  
Zishan Zhang ◽  
Suman Paul ◽  
Alexander G. Ivanov ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Photosystem Ii ◽  
Scots Pine ◽  
Photosystem I ◽  
Photosynthetic Apparatus ◽  
Chloroplast Ultrastructure ◽  
Composition Analysis ◽  
Seasonal Adjustment ◽  
Direct Energy ◽  
Direct Energy Transfer

AbstractEvergreen conifers in boreal forests can survive extremely cold (freezing) temperatures during long dark winter and fully recover during summer. A phenomenon called “sustained quenching” putatively provides photoprotection and enables their survival, but its precise molecular and physiological mechanisms are not understood. To unveil them, here we have analyzed seasonal adjustment of the photosynthetic machinery of Scots pine (Pinus sylvestris) trees by monitoring multi-year changes in weather, chlorophyll fluorescence, chloroplast ultrastructure, and changes in pigment-protein composition. Analysis of Photosystem II and Photosystem I performance parameters indicate that highly dynamic structural and functional seasonal rearrangements of the photosynthetic apparatus occur. Although several mechanisms might contribute to ‘sustained quenching’ of winter/early spring pine needles, time-resolved fluorescence analysis shows that extreme down-regulation of photosystem II activity along with direct energy transfer from photosystem II to photosystem I play a major role. This mechanism is enabled by extensive thylakoid destacking allowing for the mixing of PSII with PSI complexes. These two linked phenomena play crucial roles in winter acclimation and protection.

The Effect of Phytochrome and Proteinsynthesis-Inhibitors on the Formation of Chlorophylls and Carotenoids in Radish Seedlings Treated with Photosystem II and Bleaching Herbicides

1980 ◽  
Vol 35 (5-6) ◽  
pp. 445-450 ◽  
Author(s):  
K. H. Grumbach ◽  
M. Drollinger
Keyword(s):  
Protein Synthesis ◽  
Photosystem Ii ◽  
Carotenoid Biosynthesis ◽  
The Other ◽  
Carotenoid Content ◽  
Pigment Pattern ◽  
Inhibition Of Protein Synthesis ◽  
Terpenoid Metabolism ◽  
Radish Seedlings ◽  
Primary Action

Abstract Etioplasts of radish seedlings treated with photosystem II (DCM U, bentazon) and chlorotic herbicides (amitrole, SAN 6706) were tested on their ability to perform the phytochrome mediated chlorophyll and carotenoid biosynthesis. The cytoplasmic influence on the chloroplastic action of herbicides was also investigated by inhibition of protein synthesis either in the chloro­ plast with chloramphenicol or in the cytoplasm with actidion. In all herbicide treated radish seedlings a phytochrome mediated chlorophyll and carotenoid biosynthesis was obtained as found in control plants. In plants treated with DCM U the bio­ synthesis of carotenoids is enhanced compared to the control plants, while SAN 6706 significantly suppresses the carotenoid formation. It is concluded, that photosystem II and chlorotic herbicides do not interfere with the primary action of phytochrome but rather do develope their effects on the terpenoid metabolism through phytochrome. Chloramphenicol applied at the time of sowing very strongly suppresses the formation of chlorophylls and carotenoids in control plants. The sensitivity towards actidion is, however, very much lower. If chloramphenicol and actidion treated plants were also supplied with herbicides, the pigment pattern is completely different In SAN 6706-treated plants chloramphenicol acts synergistic, resulting in an even lower chlorophyll and carotenoid content than in plants supplied only with chloramphenicol. On the other hand SAN 6706 in combination with actidion enhances the formation of pigments, leading to a much higher chlorophyll and carotenoid content as in plants treated only with actidion. A stimulatory effect on the formation of chlorophylls and carotenoids was also found for DCMU-treated plants in combination with actidion. The observation, that in plants treated with SAN 6706 together with actidion, which inhibits protein synthesis in the cytoplasm, the herbicidal response in the chloroplast is completely abolished, gives evidence that the photooxidative action of SAN 6706 in the chloroplast is developed by the cytoplasm.

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