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1.
Huan Jing Ke Xue ; 43(1): 295-305, 2022 Jan 08.
Artigo em Chinês | MEDLINE | ID: mdl-34989514

RESUMO

The hydrodynamics and environmental factors in the Xiangxi River (XXR) and Shennong River (SNR), which are tributaries of the Three Gorges Reservoir (TGR), were monitored from July to August (the low water level period) and in October (the impoundment period) in 2018. The vertical distribution characteristics of chlorophyll a and other indicators of the two tributaries were analyzed during the different operation periods, and the factors that affected the vertical distribution in each period were discussed. The results showed that the vertical distribution of dissolved oxygen, water temperature, pH value, and chlorophyll a of the XXR and SNR during the low water level period was relatively consistent. The indexes 0-10 m (0-5 m for chlorophyll a) from the surface of the XXR and SNR, respectively, showed significant stratification and decreased with increasing water depth; the stability index of thermal stratification (RWCS/H) was 13.71-29.07 m-1, which was stable. After the water depth reached 10 m (5 m for chlorophyll a), the indexes tended to be stable along the water depth. During the impoundment period, there was no obvious stratification for each index; the stability index of thermal stratification was 0-0.5 m-1, the stability of the water body was weak, and the vertical variation of each index was relatively stable. The comprehensive trophic state index (TLI) of the XXR and SNR were 55 and 53 during the low water level period, respectively, indicating that they were in a slightly eutrophic state, and 39 and 46 during the impoundment period, respectively, indicating a mesotrophic state. Linear regression analysis showed that chlorophyll a, dissolved oxygen, water temperature, and pH in the two tributaries were significantly correlated in the vertical direction in the low water level period, indicating that dissolved oxygen, water temperature stratification, and pH were important factors affecting the vertical distribution of chlorophyll a. During the impoundment period, a large amount of backflow from the Yangtze River, a large fluctuation in tributary water level, and the decrease in RWCS/H were the important factors that affected the small vertical change in the water body. The enhancement of vertical mixing and the decrease in Zeu/Zmix were the key factors affecting the nutritional status of the water.


Assuntos
Rios , Poluentes Químicos da Água , China , Clorofila/análise , Clorofila A , Monitoramento Ambiental , Água , Poluentes Químicos da Água/análise
2.
Planta ; 255(2): 36, 2022 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-35015152

RESUMO

MAIN CONCLUSION: Decreased PG constrains PSI activity due to inhibition of transcript and polypeptide abundance of light-harvesting and reaction center polypeptides generating a reversible, yellow phenotype during cold acclimation of pgp1. Cold acclimation of the Arabidopsis pgp1 mutant at 5 °C resulted in a pale-yellow phenotype with abnormal chloroplast ultrastructure compared to its green phenotype upon growth at 20 °C despite a normal cold-acclimation response at the transcript level. In contrast, wild type maintained its normal green phenotype and chloroplast ultrastructure irrespective of growth temperature. In contrast to cold acclimation of WT, growth of pgp1 at 5 °C limited the accumulation of Lhcbs and Lhcas assessed by immunoblotting. However, a novel 43 kD polypeptide of Lhcb1 as well as a 29 kD polypeptide of Lhcb3 accumulated in the soluble fraction which was absent in the thylakoid membrane fraction of cold-acclimated pgp1 which was not observed in WT. Cold acclimation of pgp1 destabilized the Chl-protein complexes associated with PSI and predisposed energy distribution in favor of PSII rather than PSI compared to the WT. Functionally, in vivo PSI versus PSII photochemistry was inhibited in cold-acclimated pgp1 to a greater extent than in WT relative to controls. Greening of the pale-yellow pgp1 was induced when cold-acclimated pgp1 was shifted from 5 to 20 °C which resulted in a marked decrease in excitation pressure to a level comparable to WT. Concomitantly, Lhcbs and Lhcas accumulated with a simultaneous decrease in the novel 43 and 29kD polypeptides. We conclude that the reduced levels of phosphatidyldiacylglycerol in the pgp1 limit the capacity of the mutant to maintain the structure and function of its photosynthetic apparatus during cold acclimation. Thus, maintenance of normal thylakoid phosphatidyldiacylglycerol levels is essential to stabilize the photosynthetic apparatus during cold acclimation.


Assuntos
Arabidopsis , Fotossíntese , Aclimatação , Arabidopsis/genética , Arabidopsis/metabolismo , Clorofila , Temperatura Baixa , Complexos de Proteínas Captadores de Luz , Peptídeos , Fotoquímica , Complexo de Proteína do Fotossistema I/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo
3.
Biochim Biophys Acta Biomembr ; 1864(1): 183812, 2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-34743950

RESUMO

Lipid-porphyrin conjugates are considered nowadays as promising building blocks for the conception of drug delivery systems with multifunctional properties such as photothermal therapy (PTT), photodynamic therapy (PDT), phototriggerable release, photoacoustic and fluorescence imaging. For this aim, we have recently synthesized a new lipid-porphyrin conjugate named PhLSM. This was obtained by coupling pheophorbide-a (Pheo-a), a photosensitizer derived from chlorophyll-a, to egg lyso-sphingomyelin. The pure PhLSMs were able to self-assemble into vesicle-like structures that were however not stable and formed aggregates with undefined structures due to the mismatch between the length of the alkyl chain in sn-1 position and the adjacent porphyrin. Herein, stable PhLSMs lipid bilayers were achieved by mixing PhLSMs with cholesterol which exhibits a complementary packing parameter. The interfacial behavior as well as the fine structures of their equimolar mixture was studied at the air/buffer interface by the mean of Langmuir balance and x-ray reflectomerty (XRR) respectively. Our XRR analysis unraveled the monolayer thickening and the increase in the lateral ordering of PhLSM molecules. Interestingly, we could prepare stable vesicles with this mixture that encapsulate hydrophilic fluorescent probe. The light-triggered release kinetics and the photothermal conversion were studied. Moreover, the obtained vesicles were photo-triggerable and allowed the release of an encapsulated cargo in an ON-OFF fashion.


Assuntos
Sistemas de Liberação de Medicamentos , Lipídeos/química , Fosfolipídeos/química , Porfirinas/química , Clorofila/análogos & derivados , Clorofila/síntese química , Clorofila/química , Colesterol/química , Humanos , Interações Hidrofóbicas e Hidrofílicas/efeitos da radiação , Cinética , Luz , Bicamadas Lipídicas/química , Bicamadas Lipídicas/efeitos da radiação , Lipídeos/síntese química , Lipídeos/efeitos da radiação , Lipídeos/uso terapêutico , Lipossomos/química , Lipossomos/efeitos da radiação , Lipossomos/uso terapêutico , Fosfolipídeos/síntese química , Fosfolipídeos/farmacologia , Fosfolipídeos/efeitos da radiação , Fotoquimioterapia/tendências , Fármacos Fotossensibilizantes/síntese química , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/efeitos da radiação , Terapia Fototérmica/tendências , Porfirinas/síntese química , Porfirinas/efeitos da radiação , Porfirinas/uso terapêutico
4.
Sci Total Environ ; 806(Pt 1): 150507, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34583075

RESUMO

Chlorella pyrenoidosa was exposed to nonylphenol (NP) to investigate the tolerance, antioxidant response, removal efficiency, and biodegradation mechanism. We conducted studies on algal biomass, chlorophyll a content, and photosynthetic activity, and found that C. pyrenoidosa exhibited a high tolerance even at 8 mg L-1 of NP. Changes in peroxidase (POD) and superoxide dismutase (SOD) activities indicated that the NP-induced oxidative stress caused oxidant damage, which increased the malondialdehyde (MDA) content. After culturing for 120 h, the NP removal efficiency of C. pyrenoidosa was 89%, 59%, 49%, and 48% in the 2, 4, 6, and 8 mg L-1 treatment groups, respectively. Degradation intermediates determined by GC-MS suggested that the biodegradation of NP in C. pyrenoidosa originated from the long alkyl chain. In addition, transcriptome analysis indicated that NP affected photosynthesis, antioxidase, and oxidoreductase activity-related genes. In summary, our results indicated that C. pyrenoidosa is a species that exhibits high tolerance and biodegradation capacity toward NP.


Assuntos
Chlorella , Poluentes Químicos da Água , Antioxidantes , Clorofila , Clorofila A , Perfilação da Expressão Gênica , Fenóis , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
5.
Food Chem ; 372: 131173, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34601424

RESUMO

The variation of proximate compositions, amino acids, carotenoids, chlorophyll, and total cyanide contents in cassava leaves was studied to identify the most suitable leaves for human consumption. The cassava leaves from 4 cultivars were analysed at 3 leaf positions as well as at 2 plant ages. The leaves of 'Rayong 5' cultivar from the middle position at 6 months after planting contained the highest crude protein, amino acids, carotenoids, and chlorophyll. The total cyanide content was high and therefore, an effective detoxification method is needed. Protein from the cassava leaves was rich in glutamine, aspartic acid, and leucine, but low in methionine and cysteine. Additionally, cassava leaves were found to be a rich source of carotenoids and chlorophyll. This study provided the evidences that cassava leaves can be an alternative source as protein supplement and for carotenoids and chlorophyll extraction and paves the way to valorise this abundant agricultural by-product.


Assuntos
Manihot , Carotenoides/análise , Clorofila , Cianetos , Humanos , Folhas de Planta/química , Tailândia
6.
Environ Pollut ; 292(Pt A): 118268, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34610411

RESUMO

There is little information available to decipher the interaction between molybdenum (Mo) and nitric oxide (NO) in mitigating arsenic (AsV) stress in plants. The present work highlights the associative role of exogenous Mo and endogenous NO signaling in regulating AsV tolerance in wheat seedlings. Application of Mo (1 µM) on 25-day-old wheat seedlings grown in the presence (5 µM) or absence of AsV stress caused improvement of photosynthetic pigment metabolism, reduction of electrolytic leakage and reactive oxygen species (ROS), and higher accumulation of osmolytes (proline and total soluble sugars). The molybdenum treatment upregulated antioxidative enzymes, such as superoxide dismutase, ascorbate peroxidase and glutathione reductase. In addition, the accumulation of nonenzymatic antioxidants (ascorbate and glutathione) was correlated with an increase in ascorbate peroxidase and glutathione reductase activity. The application of cPTIO (endogenous NO scavenger; 100 µM) reversed the Mo-mediated effects, thus indicating that endogenous NO may accompany Mo-induced mitigation of AsV stress. Mo treatment stimulated the accumulation of endogenous NO in the presence of AsV stress. Thus, it is evident that Mo and NO-mediated AsV stress tolerance in wheat seedlings are primarily operative through chlorophyll restoration, osmolytes accumulation, reduced electrolytic leakage, and ROS homeostasis.


Assuntos
Antioxidantes , Plântula , Arseniatos , Clorofila , Molibdênio , Óxido Nítrico , Estresse Oxidativo , Triticum
7.
J Environ Manage ; 302(Pt A): 114071, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34872184

RESUMO

Understanding the response of Chlorophyll a concentration (Chl-a, an indicator of phytoplankton biomass) to environmental factors is critical for eutrophication management. Light and nutrients often act as two main limiting environmental factors in large and shallow lakes. However, the limitation status is usually not considered explicitly when building empirical relationships even though the growth limitation is the possible mechanism controlling the behaviors of these relationships. Here we chose a typical large and shallow eutrophic lake (Lake Okeechobee) to study the response of Chl-a concentration under different growth limitation conditions. Using an existed decision tree model followed by Carlson's trophic state index, monitoring data from 1994 to 2020 were classified into light-limitation, nitrogen-limitation, or phosphorus-limitation. The spatio-temporal patterns of limitation status were revealed. By subdivision of observations according to these growth limitation classes, our results demonstrated three main findings. First, algae responded differently between light limitation and nutrient limitation. Chl-a concentrations were lower with smaller variability when light was limiting than those when nutrient was limiting. In addition, the evolution of Chl-a in enduring nutrient limitation events were more dynamic. Second, limitation-specific regressions provided a more straightforward interpretation compared with those without consideration of limitation status. Chl-a ∼ nutrient relationship based on limitation classification displayed a higher R2 with a positive slope. This positive slope indicates the sensitivity of Chl-a to that specific nutrient. Moreover, response of Chl-a to phosphorus was successfully detected by identifying P-limited samples. Otherwise, the Chl-a ∼ TP response would be muted since nitrogen is the main limiting nutrient in Lake Okeechobee. Third, a spatial heterogeneity of Chl-a ∼ TN relationship was revealed by Bayesian hierarchical modelling. This indicates the necessity of focusing more on hot spots where Chl-a displays a higher sensitivity to increase of nutrient. Our findings demonstrate the advantage of developing the limitation-specific and zone-specific relationships between algal biomass and environmental factors.


Assuntos
Clorofila , Lagos , Teorema de Bayes , Clorofila A , Eutrofização
8.
Sci Total Environ ; 805: 150423, 2022 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-34818810

RESUMO

Cyanobacteria are notorious for producing harmful algal blooms that present an ever-increasing serious threat to aquatic ecosystems worldwide, impacting the quality of drinking water and disrupting the recreational use of many water bodies. Remote sensing techniques for the detection and quantification of cyanobacterial blooms are required to monitor their initiation and spatiotemporal variability. In this study, we developed a novel semi-analytical approach to estimate the concentration of cyanobacteria-specific pigment phycocyanin (PC) and common phytoplankton pigment chlorophyll a (Chl a) from hyperspectral remote sensing data. The PC algorithm was derived from absorbance-concentration relationship, and the Chl a algorithm was devised based on a conceptual three-band structure model. The developed algorithms were applied to satellite imageries obtained by the Hyperspectral Imager for the Coastal Ocean (HICO™) sensor and tested in Lake Kinneret (Israel) during strong cyanobacterium Microcystis sp. bloom and out-of-bloom times. The sensitivity of the algorithms to errors was evaluated. The Chl a and PC concentrations were estimated with a mean absolute percentage difference (MAPD) of 16% and 28%, respectively. Sensitivity analysis shows that the influences of backscattering and other water constituents do not affect the estimation accuracy of PC (~2% MAPD). The reliable PC/Chl a ratios can be obtained at PC concentrations above 10 mg m-3. The computed PC/Chl a ratio depicts the contribution of cyanobacteria to the total phytoplankton biomass and permits investigating the role of ambient factors in the formation of a complex planktonic community. The novel algorithms have extensive practical applicability and should be suitable for the quantification of PC and Chl a in aquatic ecosystems using hyperspectral remote sensing data as well as data from future multispectral remote sensing satellites, if the respective bands are featured in the sensor.


Assuntos
Cianobactérias , Ecossistema , Algoritmos , Clorofila/análise , Clorofila A , Monitoramento Ambiental , Imageamento Hiperespectral , Lagos , Tecnologia de Sensoriamento Remoto
9.
Chemosphere ; 286(Pt 3): 131674, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34392200

RESUMO

The toxic effects of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) on the marine alga Skeletonema costatum were studied, including the population dynamics, chlorophyll fluorescence characteristics, pigment content, superoxide dismutase (SOD) activity, malondialdehyde (MDA) content and morphology. High doses (200-600 µg L-1) of BDE-47 significantly suppressed the population growth of S. costatum, with a 96 h EC50 value of 293 µg L-1. Photosynthetic parameters (Fv/Fm, rETRmax and ΦPSⅡ) of photosystem II (PSII) were significantly inhibited with increasing BDE-47 concentrations. The chlorophyll c (chl c) concentration was also inhibited by exposure to BDE-47. In contrast, chl a and carotenoid concentrations were elevated after exposure to high concentrations of BDE-47 for 72 and 96 h. The SOD activity was generally higher at concentrations of 100-600 µg L-1 than those of the control when the exposure time was less than 48 h. With increasing time, the SOD activity generally decreased, and significantly higher SOD activity only occurred in the treatment with high doses of BDE-47. High MDA contents occurred after exposure for 96 h in all BDE-47 treatments. With increasing BDE-47 concentrations, drastic deformation of the silicious valve and detachment of the strutted processes were found. In addition, drastic decreases in the BDE-47 concentration in culture medium indicated the bioaccumulation of BDE-47 by S. costatum. Our results revealed multiple responses of S. costatum to BDE-47 exposure, and indicated the potential risk of BDE-47 in the East China Sea based on these responses.


Assuntos
Antioxidantes , Diatomáceas , Clorofila , Éteres Difenil Halogenados/toxicidade , Fotossíntese , Dinâmica Populacional
10.
Sci Total Environ ; 802: 149787, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34464796

RESUMO

This study aimed to determine the effect of the climatic change on the phototrophic communities of hypersaline microbial mats. Ocean acidification and warming were simulated alone and together on microbial mats placed into mesocosms. As expected, the temperature in the warming treatments increased by 4 °C from the initial temperature. Surprisingly, no significance difference was observed between the water pH of the different treatments despite of a decrease of 0.4 unit pH in the water reserves of acidification treatments. The salinity increased on the warming treatments and the dissolved oxygen concentration increased and was higher on the acidification treatments. A total of 37 pigments were identified belonging to chlorophylls, carotenes and xanthophylls families. The higher abundance of unknown chlorophyll molecules called chlorophyll derivatives was observed in the acidification alone treatment with a decrease in chlorophyll a abundance. This change in pigmentary composition was accompanied by a higher production of bound extracellular carbohydrates but didn't affect the photosynthetic efficiency of the microbial mats. A careful analysis of the absorption properties of these molecules indicated that these chlorophyll derivatives were likely bacteriochlorophyll c contained in the chlorosomes of green anoxygenic phototroph bacteria. Two hypotheses can be drawn from these results: 1/ the phototrophic communities of the microbial mats were modified under acidification treatment leading to a higher relative abundance of green anoxygenic bacteria, or 2/ the highest availability of CO2 in the environment has led to a shift in the metabolism of green anoxygenic bacteria being more competitive than other phototrophs.


Assuntos
Bacterioclorofilas , Mudança Climática , Clorofila , Clorofila A , Humanos , Concentração de Íons de Hidrogênio , Água do Mar
11.
Chemosphere ; 287(Pt 1): 132073, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34478964

RESUMO

Fomesafen is an herbicide used in soybean production, and sugar beet is a sensitive crop to fomesafen. When the herbicide is sprayed in the field, it is easy to cause floating and depositing on non-target crops, resulting in crop poisoning and reducing yield. There are few on the phenomenon and mechanism of fomesafen herbicide drift on sugar beet. There are few reports on the phenomenon and mechanism of ether herbicide migration on phytotoxicity of sugar beet. Therefore, in this experiment, indoor potted plants were used to simulate the dose of fomesafen drift deposited on sugar beet in the field to study the effects of fomesafen on the growth, photosynthetic system, and physiological indexes of seedlings for sugar beet were studied. The results showed that fomesafen at the dose of 225 g a.i. ha-1 significantly inhibited the plant height, root length, and biomass of sugar beet. Compared with the control, the net photosynthetic rate, stoma conductance, transpiration rate, and total chlorophyll pigment content of leaves were reduced by 77.16%, 83.84%, 64.00%, and 28.13%, respectively. Treatment with a dose of 225 g a.i. ha-1 also damaged the photosynthetic system II of the leaves, lowering the performance index on absorption energy, maximum quantum yield and, the energy of electron transfer, causing photoinhibition and photodamage. In addition, fomesafen significantly increased the content of malondialdehyde and the activity of peroxidase in leaves of sugar beet, reducing the activities of superoxide dismutase and catalase. Overall, this study is helpful to understand the drift and deposition of fomesafen on sugar beet and to discuss the phytotoxicity risk and dose of fomesafen on the beet, as a result of controlling the dose of fomesafen sprayed in the field.


Assuntos
Beta vulgaris , Benzamidas , Clorofila , Folhas de Planta , Açúcares
12.
Chemosphere ; 287(Pt 2): 132185, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34500328

RESUMO

Hydrogen peroxide (H2O2) is an environmental-friendly algicide and it is widely used to control algal blooms in aquatic ecosystems. However, the response of algal cell metabolic characteristics and intracellular protein profile under H2O2 stress is still not well understood. In the present study, the green alga Scenedesmus obliquus was exposed to different concentrations of H2O2 (0, 2, 6, 8 and 10 mg L-1) to evaluate the changes in algal morphological, physiological, and proteomic features to H2O2 exposure. The results showed that 8 mg L-1 of H2O2 could effectively inhibit the cell growth and photosynthetic activity of S. obliquus including chlorophyll-a content and chlorophyll fluorescence parameters. The increased activities of superoxide dismutase (SOD) and catalase (CAT) observed in this study indicate that cells exposure to H2O2 caused oxidative stress. The metabolic activity of S. obliquus was significantly decreased by H2O2 treatment. In terms of proteomic analysis, 251 differentially expressed proteins (DEPs) were successfully identified. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed significant protein enrichment in the metabolic pathways, photosynthesis, ascorbic acid, and alginate metabolism and phenylpropane biosynthesis of S. obliquus. The analysis of protein-protein interaction system shows that the pathways of photosynthesis and metabolic pathways of S. obliquus were essential to resist oxidative stress. Taking together, these results shed new lights on exploring the cell physiological metabolism and intracellular protein mechanisms of H2O2 inhibition on algal blooms.


Assuntos
Antioxidantes , Scenedesmus , Clorofila , Ecossistema , Peróxido de Hidrogênio/toxicidade , Mapeamento de Peptídeos , Proteômica
13.
Food Chem ; 366: 130577, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34293542

RESUMO

The development of green vegetable processing is still limited by the imperfect green protection now. Chlorophyll (Chl), the main pigment presented in green vegetables, was studied that the effects of NaCl on the stability of it, and the synergy of NaCl and high-pressure on Chl protection. Compared to the control, the retention of Chl was increased by 80.14% and the activation energy was 62.7% higher in 7.8% NaCl solution. When the pressure was 600 MPa with 7.8% NaCl, the synergy of NaCl and high-pressure increased the Chl retention by 100%. The restriction of NaCl to H2O provided Chl with a lower polarity environment and increased the contact between Chl molecules. And the fluorescence quenching confirmed the aggregation of Chls induced by high-pressure. This study explains the mechanism of green protection by NaCl and high-pressure, broadening the horizon for the development of color protection in vegetable processing.


Assuntos
Clorofila , Cloreto de Sódio , Espectrometria de Fluorescência
14.
Methods Mol Biol ; 2398: 33-45, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34674165

RESUMO

Monitoring prompt chlorophyll fluorescence (F) by making consecutive pulse amplitude modulation (PAM) measurements is a noninvasive, nondestructive, potentially high-throughput technique for evaluating circadian rhythms in diverse plant species. The technique is also less labor-intensive than many others currently used and requires no transgenic procedures.


Assuntos
Clorofila , Ritmo Circadiano , Fluorescência , Fotossíntese , Folhas de Planta , Plantas
15.
J Environ Manage ; 302(Pt A): 114012, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34731708

RESUMO

The volume of municipal solid waste (MSW) inputs is rapidly increasing with a growing human population, and its composition is changing due an increased diversity of materials being deposited. There is an associated increase in leachate, a common toxic byproduct of MSW facilities that must be collected and treated prior to its release into the environment. There is growing interest in plant-based methods that are economical and efficient for leachate toxicity assessment such as biological tests that use indicator species. In the present study, the tolerance thresholds of two herbaceous species, Sinapis alba L. (mustard) and Triticum aestivum L. (wheat) to increasing shares of leachate sourced from an MSW facility in the Czech Republic were assessed through a variety of physiological parameters. Soil-based biotests showed a stimulation in the shoot biomass, leaf expansion, primary root elongation and carbon assimilation rate of the selected plant species to leachate concentrations between 20 and 50 %. Higher leachate concentrations led to reductions in most physiological parameters, especially the elongation of seedling roots when growth solutions with >50 % leachate were applied. While S. alba was more sensitive to increasing proportions of leachate in terms of growth parameters of the shoot tissues, photosystem II efficiency and chlorophyll pigment concentrations were more responsive in T. aestivum, indicating species-dependent differences. The present biotests provide further support for the use of both Sinapis alba L and Triticum aestivum L. as indicator species of phytotoxicity.


Assuntos
Eliminação de Resíduos , Poluentes Químicos da Água , Clorofila , Humanos , Plântula/química , Sinapis , Resíduos Sólidos , Triticum , Instalações de Eliminação de Resíduos , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
16.
J Hazard Mater ; 424(Pt A): 127265, 2022 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-34583160

RESUMO

Nitrogen dioxide (NO2) is a common outdoor air pollutant, which has adverse effects on the environment and human health. Herein, NO2 inhibited photosynthesis and antioxidant capacity in plants. Melatonin (Mel) is a neurohormone found in the pineal gland. Exogenous Mel alleviated chlorophyll degradation and increased the expression of key proteins and genes in the process of chlorophyll synthesis in tobacco leaves exposed to NO2. Additionally, the activities of photosystem II (PSII) and photosystem I (PSI) were enhanced. PSII and PSI reaction center proteins and genes were upregulated. Mel pre-treatment enhanced enzyme activities and expression of proteins related to the ascorbic acid-glutathione cycle and thioredoxin-peroxiredoxin pathway in leaves exposed to NO2, thus regulating their redox balance. Furthermore, exogenous Mel mediated the polyamine synthesis pathway and increased the expression of the key enzyme proteins SAMS1, SAMS2, and SAMS3 in the polyamine synthesis pathway in leaves under NO2 stress. Mel regulated ABA signal transduction and calmodulin binding transcription factors CAMTA12 and NtCaM calmodulin NtCaM2 in Ca2+ signal transduction. Collectively, these results elucidate that Mel can alleviate high-concentration NO2, thus suitable for agricultural application.


Assuntos
Melatonina , Tabaco , Antioxidantes , Clorofila , Transporte de Elétrons , Homeostase , Humanos , Dióxido de Nitrogênio/toxicidade , Oxirredução , Fotossíntese , Folhas de Planta , Transdução de Sinais
17.
Plant Physiol Biochem ; 170: 206-217, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34906903

RESUMO

Pine seedlings exhibit heteroblastic foliage (primary and secondary needles) during seedling development. However, few trials have studied how heteroblastic foliage influences pine seedling growth by seasonal variation. This study first investigated the anatomical differences between the primary and secondary needles of one-year-old Pinus massoniana seedlings. We measured chlorophyll fluorescence (ChlF) and evaluated the photoprotective mechanisms and light energy partitioning of these heteroblastic leaves from September to November. The results showed that the primary needles, as juvenile foliage, had a greater fraction of mesophyll tissue and stomata. In addition, the primary needles had two vascular bundles, and shorter distance from xylem and phloem to mesophyll cells, exhibiting a luxury growth strategy of rapidly obtaining high returns. The ChlF parameters indicated that the primary needles maintained a relatively high level of photoprotection by thermal dissipation (nonphotochemical quenching (NPQ)) and nonregulated energy dissipation (Y(NO)). The secondary needles, representing mature foliage, had greater area of xylem and phloem tissues. The contents of Chl b and carotenoids (Car) significantly increased in November, promoting φPo and photoprotection, which suggested that the secondary needles were more resistant to low temperatures. During the whole light response process of secondary needles, the increases in the electron transfer rate (ETR) and light energy utilization efficiency (α) helped to increase the actual photosynthetic quantum yield (Y(II)) by reducing energy dissipation by decreasing the proportion of regulated energy dissipation (Y(NPQ)) and Y(NO). Given the sensitivity of this heteroblastic foliage to environmental changes, the practical use and extension of P. massoniana for afforestation purposes should be carried out with caution.


Assuntos
Pinus , Animais , Clorofila , Fluorescência , Fotossíntese , Folhas de Planta , Plântula , Ovinos
18.
Plant Physiol Biochem ; 170: 296-306, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34952249

RESUMO

Photosystem II efficiency is the most important aspect of stress physiology to keep photosynthetic momentum operative under stress conditions. In the last few decades effect of priming on the germination growth and physiology of plants were highlighted. Profiling energy compartmentalization in PSII using chlorophyll fluorescence kinetics and specific energy fluxes of primed seeds and plants has not been documented. It is crucial to discover the changes associated with the light-harvesting complexes, PSII functionality, and photochemical modulations occurring in the biochemical thylakoid membrane in response to priming and salt stress. The present study mainly focuses on photosystem II efficiency leading to physiological tolerance by seed priming. We grow the plants after seed priming with the solution of sodium chloride (75 and 150 mM), salicylic acid (1 and 2 mM), and calcium chloride (34 mM) and nitrate (20 mM). All the primed plants were subjected to salt stress 10 days after germination @ 0, 75, and 150 mM NaCl. Later germination, growth, morphology, physiology, PS II functionality and photochemical yield were evaluated. NaCl priming did more promising effects on energy compartmentalization, light-harvesting ability, and specific energy fluxes of photosystem II compared to salicylic acid and calcium salts under a stress environment. Maximum quantum yield (FV/FM), active reaction centers with higher efficiency of water splitting complex (FV/FO), restored electron flow, higher photochemical quenching (qP), oxygen evolution (SMT-phase), and almost negligible heat dissipation are associated with better osmotic adjustment and higher water uptake (RWC) under stress condition.


Assuntos
Complexo de Proteína do Fotossistema II , Zea mays , Clorofila , Fluorescência , Germinação , Luz , Fotossíntese , Complexo de Proteína do Fotossistema II/metabolismo , Estresse Salino , Zea mays/metabolismo
19.
Plant Sci ; 314: 111118, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34895547

RESUMO

Seedling quality greatly affects the subsequent survival, quality and yield of tomatoes. To explore the response of tomato seedlings on vertical light, we investigated the continuous trends of chlorophyll fluorescence parameters in six vertical light intensities and Pearson's correlation analysis of them. The results showed that the dark fluorescence parameters of Fm, Fv/Fm highly correlated with the photosynthetic photon flux density (PPFD) while NPQ, Y(NPQ), Y(NO) were highly correlated with the day of light processing (DLP). With increasing PPFD, the Fv/Fm decreased, the residual sum of curves increased and the scaling factor (S) was decreased. The photoinhibition phenomenon was relieved to different degrees on DLP 4. L4 (243.17 ± 4.37 µmol m-2 s-1) was the fastest light adaptation, L5 (295.34 ± 5.42 µmol m-2 s-1) was the second. ΦPSII accumulation was greatest in L4 and second in L5. Both L4 and L5 seedling health index and dry weight were significantly higher than L1 (53.20 ± 1.55 µmol m-2 s-1). L4 had the highest Chl a/b and total soluble sugar. It can be concluded that L4 was the best vertical PPFD with the highest light-adaption. The larger the PPFD, the greater the curve deviation, the greater the degree of data discretization, and the higher the photoinhibition. The more appropriate the light intensity is, the faster the seedlings light-adapted are. Therefore, the rapid and proper adjustment of light intensity is the key to obtain high quality tomato seedlings.


Assuntos
Adaptação Ocular/fisiologia , Clorofila/metabolismo , Produtos Agrícolas/fisiologia , Lycopersicon esculentum/fisiologia , Folhas de Planta/fisiologia , Plântula/fisiologia , Fluorescência
20.
Ying Yong Sheng Tai Xue Bao ; 32(12): 4381-4390, 2021 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-34951279

RESUMO

The damage mechanism of salt stress on plants has attracted much attention. In order to reveal the damage mechanism of different salt stresses, we compared osmotic regulation and photosynthetic characteristics of seedlings of wheat cultivar Xianhan 3 under sodium salt (150 mmol·L-1) and calcium salt (5, 30 mmol·L-1) treatments alone or in combination. The results showed that sodium salt or calcium salt stress alone significantly inhibited the growth of roots and stems, but increased the amount of soluble sugar and proline, regulatory energy-dissipated electron yield, non-photochemical quenching and relative content of zeaxanthin contents in leaves. In contrast, salt treatments alone significantly decreased the levels of chlorophyll a and chlorophyll b, maximum photochemical efficiency, PSⅡ photochemical efficiency, photochemical quenching and photosynthetic electron transport efficiency. Furthermore, the inhibition of wheat seedling growth was more sensitive to calcium salt than to sodium salt stress, whereas the decreases of chlorophyll content and chlorophyll fluorescence parameters were more prominent in response to sodium salt stress. Except for the amount of soluble protein, lutein and the relative level of zeaxanthin, the changes of other parameters in the leaves due to sodium salt stress were effectively blocked by the application of low calcium concentration, but further increased by the presence of high calcium salt concentration. Taken together, sodium or calcium salt stress alone significantly inhibited seedling growth. The toxicity of sodium salt to wheat seedlings was effectively alleviated by low calcium concentration, but was aggravated by high calcium concentration, which were associated with the changes of photosynthetic pigment content, light energy capture, and photosynthetic electron transport process in the leaves of wheat seedlings. Moreover, osmotic regulators played an important role in enhancing the resistance of wheat seedlings to sodium or/and calcium environment.


Assuntos
Plântula , Triticum , Clorofila , Clorofila A , Fluorescência , Fotossíntese , Folhas de Planta , Estresse Salino
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