Changes in photosynthetic apparatus of mustard (Sinapis alba) cotyledons following cycloheximide and kinetin treatments

Biologia ◽  
2008 ◽  
Vol 63 (5) ◽  
Author(s):  
Adriana Machlicová ◽  
L’udmila Slováková ◽  
Ján Hudák
Keyword(s):  
Photosynthetic Pigments ◽  
Structural Characteristics ◽  
Photosynthetic Apparatus ◽  
Chloroplast Ultrastructure ◽  
Membrane System ◽  
Sinapis Alba ◽  
Negative Effects ◽  
Chlorophyll Pigments ◽  
Leaf Mesophyll ◽  
Rubisco Subunits

AbstractBiochemical and accompanying structural characteristics of the photosynthetic process were studied in mustard seedlings cultivated on medium with increasing concentrations of cycloheximide alone as well as in combination with various kinetin concentrations. After 7 days of cultivation the contents of total chlorophyll, carotenoids and content of Rubisco in mustard cotyledons were determined. The content of chlorophyll pigments and carotenoids decreased in dependence of cycloheximide concentration. Following antibiotic treatment the content of both Rubisco subunits markedly decreased. In addition cycloheximide caused disturbance in mesophyll organization and chloroplast ultrastructure.Kinetin applied with cycloheximide increased the amount of photosynthetic pigments as well as of Rubisco, compared to the cycloheximide alone. In the seedlings treated with cycloheximide+kinetin the structure of leaf mesophyll and chloroplast membrane system was similar to control. Our results indicate that kinetin diminished the negative effects of cycloheximide on photosynthetic pigments and Rubisco as well as on the structural traits of the cotyledons.

Content of Photosynthetic Pigments and Leaf Gas Exchanges of Young Coffee Plants under Light Restriction and Treated with Paclobutrazol

2019 ◽  
pp. 1-13
Author(s):  
André Felipe Fialho Ribeiro ◽  
Sylvana Naomi Matsumoto ◽  
Luanna Fernandes Pereira ◽  
Ueliton Soares De Oliveira ◽  
Ednilson Carvalho Teixeira ◽  
...  
Keyword(s):  
Photosynthetic Pigments ◽  
Photosynthetic Pigment ◽  
Photosynthetic Apparatus ◽  
Atmospheric Temperature ◽  
Joint Analysis ◽  
Negative Effects ◽  
Gas Exchanges ◽  
High Solar Radiation ◽  
Leaf Gas Exchanges ◽  
Coffee Plants

The use of shading and paclobutrazol in coffee plants can be an important cultivation strategy to mitigate the negative effects of high solar radiation and atmospheric temperature. Therefore, the levels of photosynthetic pigments and foliar gas exchanges of young coffee plants submitted to doses of paclobutrazol were evaluated, in environments with artificial light restriction. Five experiments were performed: one in full sunlight and four in artificially shaded environments with black polyethylene meshes at 20%, 40%, 60% and 80% levels of light restriction. In each of these environments, an experiment was carried out, consisting of five treatments, defined by the application of paclobutrazol via substrate, at doses of 0, 10, 20, 30 and 40 mg of active ingredient per plant. Joint analysis of experiments and analysis of variance of the regression were made, for the study of levels of shading and doses of paclobutrazol. The light restriction optimized the photosynthetic apparatus of the plants, mainly at levels close to 60%, and considerably favored leaf gas exchanges of arabica coffee. The application of paclobutrazol in the studied dosages resulted in little or no effect on photosynthetic pigment contents and did not influence leaf gas exchanges of coffee plants.

scholarly journals Light Quality-Dependent Regulation of Non-Photochemical Quenching in Tomato Plants

Biology ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 721
Author(s):  
Magdalena Trojak ◽  
Ernest Skowron
Keyword(s):  
Photosynthetic Pigments ◽  
Photosynthetic Apparatus ◽  
Photosynthetic Performance ◽  
Photochemical Quenching ◽  
Light Spectrum ◽  
Negative Effects ◽  
Tomato Plants ◽  
Lower Amplitude ◽  
Non Photochemical Quenching

Photosynthetic pigments of plants capture light as a source of energy for photosynthesis. However, the amount of energy absorbed often exceeds its utilization, thus causing damage to the photosynthetic apparatus. Plants possess several mechanisms to minimize such risks, including non-photochemical quenching (NPQ), which allows them to dissipate excess excitation energy in the form of harmless heat. However, under non-stressful conditions in indoor farming, it would be favorable to restrict the NPQ activity and increase plant photosynthetic performance by optimizing the light spectrum. Towards this goal, we investigated the dynamics of NPQ, photosynthetic properties, and antioxidant activity in the leaves of tomato plants grown under different light qualities: monochromatic red (R), green (G), or blue (B) light (L) at 80 µmol m−2 s−1 and R:G:B = 1:1:1 (referred to as the white light (WL)) at 120 µmol m−2 s−1. The results confirm that monochromatic BL increased the quantum efficiency of PSII and photosynthetic pigments accumulation. The RL and BL treatments enhanced the NPQ amplitude and showed negative effects on antioxidant enzyme activity. In contrast, plants grown solely under GL or WL presented a lower amplitude of NPQ due to the reduced accumulation of NPQ-related proteins, photosystem II (PSII) subunit S (PsbS), PROTON GRADIENT REGULATION-LIKE1 (PGRL1), cytochrome b6f subunit f (cytf) and violaxanthin de-epoxidase (VDE). Additionally, we noticed that plants grown under GL or RL presented an increased rate of lipid peroxidation. Overall, our results indicate the potential role of GL in lowering the NPQ amplitude, while the role of BL in the RGB spectrum is to ensure photosynthetic performance and photoprotective properties.

scholarly journals Phytotoxicity of Silver Nanoparticles on Tobacco Plants: Evaluation of Coating Effects on Photosynthetic Performance and Chloroplast Ultrastructure

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 744
Author(s):  
Petra Peharec Štefanić ◽  
Karla Košpić ◽  
Daniel Mark Lyons ◽  
Lara Jurković ◽  
Biljana Balen ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Cetyltrimethylammonium Bromide ◽  
Photosynthetic Apparatus ◽  
Chloroplast Ultrastructure ◽  
Photosynthetic Performance ◽  
Pigment Content ◽  
Inhibitory Effects ◽  
Tobacco Plants ◽  
Agriculture And Food ◽  
The Impact

Silver nanoparticles (AgNPs) are the most exploited nanomaterial in agriculture and food production, and their release into the environment raises concern about their impact on plants. Since AgNPs are prone to biotransformation, various surface coatings are used to enhance their stability, which may modulate AgNP-imposed toxic effects. In this study, the impact of AgNPs stabilized with different coatings (citrate, polyvinylpyrrolidone (PVP), and cetyltrimethylammonium bromide (CTAB)) and AgNO3 on photosynthesis of tobacco plants as well as AgNP stability in exposure medium have been investigated. Obtained results revealed that AgNP-citrate induced the least effects on chlorophyll a fluorescence parameters and pigment content, which could be ascribed to their fast agglomeration in the exposure medium and consequently weak uptake. The impact of AgNP-PVP and AgNP-CTAB was more severe, inducing a deterioration of photosynthetic activity along with reduced pigment content and alterations in chloroplast ultrastructure, which could be correlated to their higher stability, elevated Ag accumulation, and surface charge. In conclusion, intrinsic properties of AgNP coatings affect their stability and bioavailability in the biological medium, thereby indirectly contributing changes in the photosynthetic apparatus. Moreover, AgNP treatments exhibited more severe inhibitory effects compared to AgNO3, which indicates that the impact on photosynthesis is dependent on the form of Ag.

scholarly journals Nano Zinc-Oxide Enhanced Photosynthetic Apparatus and Photosystem Efficiency of Maize (Zea Mays L.) in Sandy-Acidic Soils

2022 ◽  
Author(s):  
Wiqar Ahmad ◽  
Jaya Nepal ◽  
Xiaoping Xin ◽  
Zhenli He
Keyword(s):  
Zinc Oxide ◽  
Plant Height ◽  
Photosynthetic Apparatus ◽  
Foliar Spray ◽  
Growth And Yield ◽  
Photochemical Quenching ◽  
Nano Zno ◽  
Chlorophyll Pigments ◽  
Spad Value ◽  
Application Methods

Abstract Conventional Zinc (Zn) fertilization (e.g., zinc sulfate) often leads to poor availability in soils. Zinc oxide nanoparticles (nano ZnO) can be a potential solution, but their effect on crop photosynthetic activity isn’t well documented. The effects of nano ZnO (50, 100, 150, 200 mg L-1) and application methods (seed-coating, soil-drench, and foliar-spray) in comparison with ZnSO4 recommended dose were evaluated for plant height, biomass, chlorophyll pigments and photosystem efficiency in a greenhouse pot experiment. 100 mg L-1 of nano ZnO significantly increased the chlorophyll (Chl.) a, b, a+b, carotenoids (x+c), a+b/x+c, SPAD, leaf Chl., total chlorophyll content plant-1, plant height and total biological yield (by 18-30%, 33-67%, 22-38%, 14-21%, 14-27%, 12-19%, 12-23% 58-99%, 6-11% and 16-20%, respectively) and reduced Chl. a/b (by 6-22%) over the other treatments (p<0.01) irrespective of application methods. Nano ZnO applied at 100 mg L-1 significantly increased photochemical quenching (qP) and efficiency of photosystem II (EPSII) compared to 150 and 200 mg L-1 regardless of application methods. The positive correlations between Chl. a and Chl. b (r2 0.90), Chl. a+b and x+c (r2=0.71), SPAD and Chl. a (r2=0.90), SPAD and Chl. b (r2=0.94) and SPAD and Chl. a+b (r2=0.93) indicates a uniform enhancement in chlorophyll pigments; SPAD value, qP, EPSII, and growth and yield parameters. This elucidates that the application of nano ZnO at 100 mg L-1 promotes corn biochemical health and photosynthesis, irrespective of the application method. These findings have a great propounding for improving plant growth through nano ZnO bio-fortification in acidic Spodosols.

scholarly journals Dust Pollution Reduced Stomatal Conductance and Photosynthetic Pigments of Selected Medicinal Plants Growing at Lokpa Ukwu Quarry Site in Abia State, Nigeria

2020 ◽  
pp. 1-11
Author(s):  
C. E. Ogbonna ◽  
F. I. Nwafor ◽  
N. O. Nweze
Keyword(s):  
Stomatal Conductance ◽  
Medicinal Plants ◽  
Photosynthetic Pigments ◽  
Total Chlorophyll ◽  
Negative Effects ◽  
Dust Pollution ◽  
Standard Procedures ◽  
Maximum Conductance ◽  
Clearing Method ◽  
Β Carotene

Aims: We investigated the influence of dust pollution on stomatal conductance and photosynthetic pigments in some medicinal plants growing at Lokpa Ukwu quarry site, Abia State, Nigeria. Place and Duration of Study: Samples were collected from Lokpa Ukwu, Abia State while laboratory analyses were carried out in the Department of Pharmacognosy and Environmental Medicines, University of Nigeria, Nsukka between February and April, 2019. Methodology: A total of nine (9) plants were sampled for the study. Leaf epidermises were prepared by clearing method and stomata were observed and studied quantitatively. Stomatal conductance was estimated from the anatomical variables following standard procedures. Total chlorophyll and β-carotene contents were also analysed and compared with control groups. Results: We observed some physiological changes in the plants from dust-polluted site such as stretched epidermal cells, deformed stomata and plasmolysed guard cells. It reduced the potential conductance indices (PCI) of the plants by 87.4% in Aspilia africana and 67% in Chromolaena odorata. The least reduction in PCI was observed in Celosia trigyna (7.2%). Operating conductance (gop) and maximum conductance (gmax) were reduced by 69.2% and 72.3% in C. odorata and A. africana respectively. Celosia trigyna was least affected with percentage reductions of 18.3% and 1.4% for gop and gmax respectively. Reduction in PCI and gmax followed the order: C. trigyna ˂ C. papaya ˂ P. discoideus ˂ D. oliveri ˂ T. rhomboidea ˂ T. orientalis ˂ V. doniana ˂ C. odorata ˂ A. africana. Total chlorophyll and β-carotene contents were reduced the most in V. doniana (45.73%) and C. odorata (40.31%) respectively and least reduced in T. orientalis by 19.54% and 13.24% respectively. Conclusion: Our findings validate previous reports of negative effects of dust pollution from quarry industries on both humans and plants alike.

scholarly journals Can Ceylon Leadwort (Plumbago zeylanica L.) Acclimate to Lead Toxicity?—Studies of Photosynthetic Apparatus Efficiency

2020 ◽  
Vol 21 (5) ◽  
pp. 1866 ◽  
Author(s):  
Krzysztof M. Tokarz ◽  
Wojciech Makowski ◽  
Barbara Tokarz ◽  
Monika Hanula ◽  
Ewa Sitek ◽  
...  
Keyword(s):  
Antioxidant Enzymes ◽  
Photosynthetic Apparatus ◽  
Chloroplast Ultrastructure ◽  
Lead Toxicity ◽  
Protein Accumulation ◽  
Fluorescence Measurement ◽  
Reaction Centre ◽  
Donor Side ◽  
Plumbago Zeylanica ◽  
Pb Concentration

Ceylon leadwort (Plumbago zeylanica) is ornamental plant known for its pharmacological properties arising from the abundant production of various secondary metabolites. It often grows in lead polluted areas. The aim of presented study was to evaluate the survival strategy of P. zeylanica to lead toxicity via photosynthetic apparatus acclimatization. Shoots of P. zeylanica were cultivated on media with different Pb concentrations (0.0, 0.05, and 0.1 g Pb∙l−1). After a four-week culture, the efficiency of the photosynthetic apparatus of plants was evaluated by Chl a fluorescence measurement, photosynthetic pigment, and Lhcb1, PsbA, PsbO, and RuBisCo protein accumulation, antioxidant enzymes activity, and chloroplast ultrastructure observation. Plants from lower Pb concentration revealed no changes in photosynthetic pigments content and light-harvesting complex (LHCII) size, as well as no limitation on the donor side of Photosystem II Reaction Centre (PSII RC). However, the activity and content of antioxidant enzymes indicated a high risk of limitation on the acceptor side of Photosystem I. In turn, plants from 0.1 g Pb∙l−1 showed a significant decrease in pigments content, LHCII size, the amount of active PSII RC, oxygen-evolving complex activity, and significant remodeling of chloroplast ultrastructure indicated limitation of PSII RC donor side. Obtained results indicate that P. zeylanica plants acclimate to lead toxicity by Pb accumulation in roots and, depending on Pb concentration, by adjusting their photosynthetic apparatus via the activation of alternative (cyclic and pseudocyclic) electron transport pathways.

scholarly journals Plant development, gas exchanges and pigments of Mesosphaerum suaveolens submitted to osmoconditioning and saline stress

2020 ◽  
Vol 80 (1) ◽  
Author(s):  
Francisco Romário Andrade Figueiredo ◽  
Jackson Silva Nóbrega ◽  
Reynaldo Teodoro de Fátima ◽  
Toshik Iarley da Silva ◽  
Rodrigo Garcia da Silva Nascimento ◽  
...  
Keyword(s):  
Irrigation Water ◽  
Saline Water ◽  
Block Design ◽  
Statistical Design ◽  
Saline Stress ◽  
Negative Effects ◽  
Gas Exchanges ◽  
Chlorophyll Pigments ◽  
Randomized Block Design ◽  
Dry Biomass

Salinity is one of the main plant abiotic stresses which affects the establishment and development crops. Hence, the search for technologies that minimize the damage caused by salinity is essential. The aim of the present work was to evaluate the effect of salinity stress and osmotic conditioning of seeds on the biomass, gas exchanges and chlorophyll pigments in Mesosphaerum suaveolens (L.) Kuntze. The statistical design adopted was a randomized block design, combined according to the Central Composite Design, referring to electrical conductivities of irrigation water and osmotic potentials, with minimum (- α) and maximum (α) values of 0.5 and 10.0 dS m-1 and 0.0 and -1.0 MPa, respectively, totaling nine combinations. The characteristics of dry biomass, gas exchange and chlorophyll indices were evaluated at 45 days after irrigation with saline water started. The salinity of irrigation water severely affected the dry biomass and the gas exchanges of M. suaveolens. Irrigation water of electrical conductivity above 3.2 dS m-1 caused reductions in chlorophyll a, b and total contents in M. suaveolens plants. Seed osmoconditioning did not attenuate the negative effects of saline stress on M. suaveolens plants.

Phytotoxic Action of Paraquat on the Photosynthetic Apparatus

1978 ◽  
Vol 33 (9-10) ◽  
pp. 688-694 ◽  
Author(s):  
Peter Böger ◽  
K. J. Kunert
Keyword(s):  
Photosystem Ii ◽  
Redox Reactions ◽  
Photosynthetic Apparatus ◽  
Membrane System ◽  
Culture Conditions ◽  
Terminal Part ◽  
Photosynthetic Membrane ◽  
Redox Chain ◽  
Chlorophyll Bleaching ◽  
Chloroplast Volume

Abstract Treatment of microalgae (Bumilleriopsis) with paraquat (1,1-dimethyl-4,4-dipyridylium dichloride) under culture conditions in the light for 20 or 160 h leads to light-induced oxygen uptake and more or less severe chlorophyll bleaching, which is accompanied by formation of malondial-dehyde. The ratio of chlorophyll to packed chloroplast volume remains about the same as that of the control, presumably indicating destruction of membranes concurrently with pigments. Unre­lated to retardation of growth, degree of bleaching or to the formation of malondialdehyde quite a uniform degree of inactivation (≈ 50%) of partial redox reactions is observed in the region of photosystem II and I except for the terminal part of photosystem I (pigment 700 → NADP+) . The action of paraquat in the cell centers primarily on the photosynthetic membrane system and redox chain.

La photorespiration se déroulant dans un air sans CO2 a-t-elle une fonction?

1978 ◽  
Vol 56 (17) ◽  
pp. 2128-2137 ◽  
Author(s):  
Gabriel Cornic
Keyword(s):  
Light Intensity ◽  
Photosynthetic Apparatus ◽  
Qualitative Change ◽  
Sinapis Alba ◽  
Inhibitory Effect ◽  
High Light Intensity ◽  
Long Term Effects ◽  
Net Assimilation ◽  
The Warburg Effect

Long-term effects of a low O2 and CO2, atmosphere on photosynthesis were studied on Sinapis alba L. It was shown that this could induce strong and durable changes on the subsequent photosynthesis measured at different CO2 and O2 concentrations. Two mains effects were observed: (1) an inhibition of net assimilation measured at 21% or 0.1% O2; (2) a qualitative change of the Warburg effect. After the treatment, high CO2 concentrations did not reverse the inhibitory effect of O2 on photosynthesis.The effect of the low O2 and CO2 atmosphere, characterized by the inhibition of net assimilation, was analyzed by varying the following factors during plants treatment: light intensity, temperature, and CO2 and O2 concentrations. The inhibition was higher under high light intensity, increased with temperature, and was apparent within the following limits of CO2 and O2 concentration, respectively, 0 to 0.018% CO2 and 0.1 to 4% O2.The results are discussed to determine if they showed that an inhibition of photorespiration in a low CO2 atmosphere has a function in the photosynthetic apparatus.

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