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32. Higher activity of PSI compared to PSII accounts for the beneficial effect of silicon on barley (Hordeum vulgare L.) plants challenged with salinity

Creator:
Falouti, M., Ellouzi, H., Bounaouara, F., Farhat, N., Aggag, A. M., Debez, A., Rabhi, M., Abdelly, C., Slama, I., and Zorrig, W.
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
chlorophyll fluorescence, growth, malondialdehyde, PSI oxidation, and potassium nutrition
Language:
Multiple languages
Description:
This study was conducted to assess whether silicon (Si) supply can alleviate the harmful effects of severe salinity in barley (Hordeum vulgare). Plants were grown on non-saline (0 mM NaCl) or saline (200 mM NaCl) nutrient media supplemented or not with 0.5 mM Si. Salinity impacted plant morphology and induced sodium and chloride accumulation within plant tissues. It significantly affected almost all measured parameters. Interestingly, Si supply alleviated salt stress effects on plant morphology, growth (up to +59%), water status (up to +74%), membrane integrity (up to +35%), pigment contents (up to +121%), and the activity of the two photosystems (PSI and PSII) by improving their yields, and by reducing their energy dissipation. Si beneficial effect was more pronounced on PSI as compared to PSII. As a whole, data inferred from the present study further confirmed that silicon application is an effective approach to cope with salinity.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

33. Impacts of low pH and low salinity induced by acid rain on the photosynthetic activity of green tidal alga Ulva prolifera

Creator:
Zhao, Z.F., Liu, Z.Y., Qin, S., Wang, X.H., Song, W.L., Liu, K., Zhuang, L.C., Xiao, S.Z., and Zhong, Z.H.
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
acid rain, chlorophyll fluorescence, nonphotochemical quenching, photosynthetic activity, and Ulva prolifera
Language:
Multiple languages
Description:
Acid rain is a serious environmental problem and has obvious impacts on the growth, reproduction, and photosynthesis of terrestrial plants. Ulva prolifera, a main blooming species of green tides, was studied on its physiological response to acid rain. The photosynthetic parameters were determined under different conditions (salinity: 1, 10, 30‰; pH: 3.0, 3.5, 4.5; duration: 0.5, 1.0, 2.0 h) followed by 24-h recovering under natural conditions. Results showed 1-h treatment with pH 3.5 caused 50-70% reduction in the maximal quantum yield of PSII photochemistry (Fv/Fm) and effective quantum yield of PSII photochemistry (ФPSII) at normal salinity but when the low pH was combined with a salinity of 10‰ or lower, PSII activity was almost completely inhibited. Moreover, the low salinity (1‰ and 10‰) reduced the degree of photoprotection under low pH (3.5) conditions. Finally, we speculated if the pH of acid rain ≤ 3.5, with 1‰ salinity and 2-h rainfall time, the amount of U. prolifera and the scale of green tides would decrease.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

34. Improvement in the photoprotective capability benefits the productivity of a yellow-green wheat mutant in N-deficient conditions

Creator:
Zhang, X. H., Li, H. X., Zhuo, G., He, Z. Z., Zhang, C. Y., Shi, Z., Li, C. C., and Wang, Y.
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
nitrogen application rate, photoprotection, photosynthetic N-use efficiency, wheat, and yellow-green mutant
Language:
Multiple languages
Description:
Wheat yellow-green mutant Jimai5265yg has a more efficient photosynthetic system and higher productivity than its wild type under N-deficient conditions. To understand the relationship between photosynthetic properties and the grain yield, we conducted a field experiment under different N application levels. Compared to wild type, the Jimai5265yg flag leaves had higher mesophyll conductance, photosynthetic N-use efficiency, and photorespiration in the field without N application. Chlorophyll a fluorescence analysis showed that PSII was more sensitive to photoinhibition due to lower nonphotochemical quenching (NPQ) and higher nonregulated heat dissipation. In N-deficient condition, the PSI acceptor side of Jimai5265yg was less reduced. We proposed that the photoinhibited PSII protected PSI from over-reduction through downregulation of electron transport. PCA analysis also indicated that PSI photoprotection and electron transport regulation were closely associated with grain yield. Our results suggested that the photoprotection mechanism of PSI independent of NPQ was critical for crop productivity.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

35. In honor of Hartmut Karl Lichtenthaler

Creator:
Govindjee, G.
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
Rabinowitch, Eugene, 1901-1973, Calvin, Melvin, 1911-1997, Emerson, Robert, chlorophyll fluorescence imaging, isoprenoid biosynthesis, phylloquinone, 2, and 581
Language:
Multiple languages
Description:
We honor here Hartmut Karl Lichtenthaler, a pioneer of plant physiology, plant biochemistry, plant biophysics, plant molecular biology, and stress physiology. His contributions to the ingenious use of chlorophyll a fluorescence imaging in understanding the physiological processes in leaves stand out. We wish him many happy and productive years of research and educating others., G. Govindjee., and Obsahuje bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

36. Insights into nanoparticle-induced changes in plant photosynthesis

Creator:
Ghorbanpour, M., Movahedi, A., Hatami, M., Kariman, K., Bovand, F., and Shahid, M.A.
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
chlorophyll, chloroplast, nanoparticles, and photosynthesis
Language:
Multiple languages
Description:
Photosynthesis can be affected by nanoparticles (NPs) both negatively (e.g., through decreasing the chlorophyll content and electron transport rate, damages to chloroplast components, etc.) or positively (e.g., via enhancing chlorophyll content, the activity of Rubisco enzyme, the performance of PSII, and CO2 harvesting, as well as broadening the chloroplast photoabsorption spectrum). Enhanced photosynthetic efficiency could be a possible impact of NPs on photosynthetic organisms of major economic and ecological significance (e.g., crops and algae), which warrants an in-depth understanding of NPs interactions with chloroplast and its structural components (e.g., thylakoid membranes), signaling molecules, and pathways involved in photosynthesis. In this review, we comprehensively explore the potential effects of NPs on photosynthesis in different photosynthetic organisms (terrestrial plants, aquatic plants, and algae), and highlight research limitations and possible practical implications.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

37. Intersections: photosynthesis, abiotic stress, and the plant microbiome

Creator:
Demmig-Adams, B., Polutchko, S. K., Zenir, M. C. , Fourounjian, P., Stewart, J. J., López-Pozo, M., and Adams III, W. W.
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
carbohydrate, electron transport, homeostasis, nitrogen, reactive oxygen species, and redox signaling
Language:
Multiple languages
Description:
Climate change impacts environmental conditions that affect photosynthesis. This review examines the effect of combinations of elevated atmospheric CO2, long photoperiods, and/or unfavorable nitrogen supply. Under moderate stress, perturbed plant source-sink ratio and redox state can be rebalanced but may result in reduced foliar protein content in C3 plants and a higher carbon-to-nitrogen ratio of plant biomass. More severe environmental conditions can trigger pronounced photosynthetic downregulation and impair growth. We comprehensively evaluate available evidence that microbial partners may be able to support plant productivity under challenging environmental conditions by providing (1) nutrients, (2) an additional carbohydrate sink, and (3) regulators of plant metabolism, especially plant redox state. In evaluating the latter mechanism, we note parallels to metabolic control in photosymbioses and microbial regulation of human redox biology.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

39. Leaf structure and photosynthesis in Populus alba under naturally fluctuating environments

Creator:
Lin, X. Y., Wang, X. X., Zeng, Q. Y., and Yang, Q.
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
fluctuating conditions, photoinhibition, photosynthesis, plasticity, and Populus alba
Language:
Multiple languages
Description:
The ability to modulate photosynthesis is essential for plants to adapt to fluctuating growing conditions. Populus species show high tolerance to various and highly variable environments. To understand their response strategies against fluctuating environments, this study investigated the morphological and physiological differences of white poplar (Populus alba) leaves when grown in a phytotron, glasshouse, and field. Our results show that the palisade cells were elongated in the field, which would enhance intercellular CO2 exchange. Photosynthetic capacity was the highest in the field leaves, as shown by higher electron transport rates (1.8 to 6.5 times) and carbon assimilation rates (2.7 to 4.2 times). The decrease of PSI acceptor-side limitation and increase of PSI donor-side limitation suggests changes in PSI redox status may contribute to photoprotection. This plasticity of white poplar allows adjusting its structure and photosynthesis under fluctuating conditions, which may partly enable its outstanding tolerance against environmental changes.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

40. Light quality, oxygenic photosynthesis and more

Creator:
Lazar, D., Stirbet, A., Björn, L. O., and Govindjee, G.
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
Chl fluorescence induction, chromatic acclimation of cyanobacteria, photoreceptors, photosynthetic pigments, photosystems I and II, and stomatal and chloroplast photoinduced movements
Language:
Multiple languages
Description:
Oxygenic photosynthesis takes place in thylakoid membranes (TM) of cyanobacteria, algae, and higher plants. It begins with light absorption by pigments in large (modular) assemblies of pigment-binding proteins, which then transfer excitation energy to the photosynthetic reaction centers of photosystem (PS) I and PSII. In green algae and plants, these light-harvesting protein complexes contain chlorophylls (Chls) and carotenoids (Cars). However, cyanobacteria, red algae, and glaucophytes contain, in addition, phycobiliproteins in phycobilisomes that are attached to the stromal surface of TM, and transfer excitation energy to the reaction centers via the Chl a molecules in the inner antennas of PSI and PSII. The color and the intensity of the light to which these photosynthetic organisms are exposed in their environment have a great influence on the composition and the structure of the light-harvesting complexes (the antenna) as well as the rest of the photosynthetic apparatus, thus affecting the photosynthetic process and even the entire organism. We present here a perspective on 'Light Quality and Oxygenic Photosynthesis', in memory of George Christos Papageorgiou (9 May 1933-21 November 2020; see notes a and b). Our review includes (1) the influence of the solar spectrum on the antenna composition, and the special significance of Chl a; (2) the effects of light quality on photosynthesis, measured using Chl a fluorescence; and (3) the importance of light quality, intensity, and its duration for the optimal growth of photosynthetic organisms.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public