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1.
J Agric Food Chem ; 68(8): 2528-2538, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-32011878

RESUMO

Albino became a novel kind of tea cultivar in China recently. In this study, transcriptome and whole-genome bisulfite sequencing (WGBS) were employed to investigate the shading effects on leaf color conversion and biosynthesis of three major secondary metabolites in the albino tea cultivar "Yujinxiang". The increased leaf chlorophyll level was likely the major cause for shaded leaf greening from young pale or yellow leaf. In comparison with the control, the total catechin level of the shading group was significantly decreased and the abundance of caffeine was markedly increased, while the theanine level was nearly not influenced. Meanwhile, differentially expressed genes (DEGs) enriched in some biological processes and pathways were identified by transcriptome analysis. Furthermore, whole-genome DNA methylation analysis revealed that the global genomic DNA methylation patterns of the shading period were remarkably altered in comparison with the control. In addition, differentially methylated regions (DMRs) and the DMR-related DEG analysis indicated that the DMR-related DEGs were the critical participants in biosynthesis of the major secondary metabolites. These findings suggest that DNA methylation is probably responsible for changes in the contents of the major secondary metabolites in Yujinxiang.


Assuntos
Camellia sinensis/metabolismo , Folhas de Planta/efeitos da radiação , Metabolismo Secundário/efeitos da radiação , Camellia sinensis/genética , Camellia sinensis/efeitos da radiação , Clorofila/biossíntese , Cor , Regulação da Expressão Gênica de Plantas , Luz , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
2.
Photochem Photobiol Sci ; 19(2): 180-192, 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-31956889

RESUMO

UV radiation affects the biochemical, physiological and morphological responses of plants. The effect is most pronounced at high altitude, such as alpine regions, and low latitude environments. The effect of UV radiation is impacted by different environmental conditions including temperature. We examined the response of the alpine plant Saxifraga hostii Tausch subsp. hostii growing at two altitudes (montane, 1100 m a.s.l. and alpine, 1500 m a.s.l.) in the Slovenian Alps. Selected ecophysiological, anatomical and pigment analyses along with measurements of the leaf optical properties were carried out during the growing season from July to September. Plants were grown under two different UV levels, near-ambient UV (UV) and reduced UV (UV-) radiation, and temperature conditions were monitored at both altitudes. Saxifraga hostii exhibited high photochemical efficiency of photosystem II and stomatal conductance under near-ambient UV radiation in August, which indicates that it is a well-acclimated plant. In September, photochemical efficiency was higher under reduced UV at the alpine altitude which together with a lower photosynthetic pigment content indicate delayed senescence for plants growing under reduced UV. Most leaf tissue thicknesses were not affected by UV radiation and altitude difference. There was a trend of increased stomatal density and reduced stomatal length on both leaf surfaces under near-ambient UV in August. However, there was no effect of UV attenuation or location at the alpine or montane site on the content of UV-B absorbing compounds, which implies the plant's tolerance of UV-B radiation. Saxifraga hostii leaves showed high absorption in the UV spectrum at higher altitudes, as shown by their optical properties. This study shows that Saxifraga hostii is well-acclimated to ambient UV radiation and to the environmental conditions at both altitudes. The effect of UV radiation is impacted by site conditions and this produces diverse plant responses, which contribute to the specific functional traits of Saxifraga hostii in the high-altitude environment.


Assuntos
Saxifragaceae/efeitos da radiação , Raios Ultravioleta , Altitude , Carotenoides/metabolismo , Clorofila A/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/anatomia & histologia , Folhas de Planta/metabolismo , Folhas de Planta/efeitos da radiação , Análise de Componente Principal , Saxifragaceae/crescimento & desenvolvimento , Saxifragaceae/metabolismo , Estações do Ano , Eslovênia , Temperatura Ambiente
3.
J Agric Food Chem ; 68(4): 961-974, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31910000

RESUMO

Manipulating light transmission by shading is the most effective method of improving the nutritional value and sensory qualities of tea. In this study, the metabolic profiling of two tea cultivars ("Yulv" and "Maotouzhong") in response to different shading periods during the summer season was performed using ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS) and gas chromatography-mass spectrometry (GC-MS). The metabolic pathway analyses showed that the glycolytic pathway and the tricarboxylic acid cycle (TCA cycle) in the leaves and shoots of "Maotouzhong" were significantly inhibited by long-term shading. The nitrogen metabolism in the leaves of the two cultivars was promoted by short-term shading, while it was inhibited by long-term shading. However, the nitrogen metabolism in the shoots of the two cultivars was always inhibited by shading, whether for short or long-term periods. In addition, the intensity of the flavonoid metabolism in both tea cultivars could be reduced by shading. These results revealed that shading could regulate the carbon and nitrogen metabolism and short-term shading could improve the tea quality to some extent.


Assuntos
Camellia sinensis/metabolismo , Camellia sinensis/efeitos da radiação , Carbono/metabolismo , Nitrogênio/metabolismo , Folhas de Planta/química , Camellia sinensis/química , Cromatografia Líquida , Produção Agrícola , Flavonoides/química , Flavonoides/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Luz , Metabolômica , Folhas de Planta/metabolismo , Folhas de Planta/efeitos da radiação , Espectrometria de Massas em Tandem
4.
J Photochem Photobiol B ; 202: 111726, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31816516

RESUMO

The objective of the study was to investigate the effects of growth-stage specific lighting for the physiological homeostasis of red leaf lettuce (Lactuca sativa L. cv. Red Cos), by measuring the productivity of photosynthesis and primary metabolism. In the experiments, the main photosynthetic photon flux consisted of red (R) and blue (B) light, supplemented with blue, green (G) or UV-A wavelengths. Decrease of fructose, accompanied by significant decrease of stomatal conductance (gs), the ratio of intracellular to ambient CO2 concentration (Ci/Ca), photosynthetic rate (Pr), light adapted actual quantum yield of PSII photochemistry (ΦPSII), biomass formation and significant increase of transpiration rate (Tr) suggest that supplemental UV-A during maturity stage, after supplemental green irradiation during seedling stage (BRG to BRUV) was the least favourable condition for red leaf lettuce. However, constant irradiation with supplemental green (BRG) or supplemental green irradiation after increased blue exposure (B↑R to BRG) resulted in significant increase of Pr, gs, Ci/Ca, and light use efficiency(LUE), and decrease of Tr and Water use efficiency (WUE). Significant increase of leaf area was observed under supplemental green in both seedlings (BR; BRG) and matured plants (B↑R to BRG). Significant increase of specific leaf area was found under supplemental green (BRG) for seedlings and under increased blue (B↑R) for matured plants. Accordingly, the most favourable growth-stage specific lighting spectrum strategy for red leaf lettuce, based on photosynthetic and primary metabolite response, is supplemental green irradiation after increased blue exposure (B↑R to BRG), whereas, the most favourable condition for seedlings is BRG. According to the PCA correlation matrix, associations among the measured data indicate that WUE negatively correlated with gs and Ci/Ca, while LUE positively correlated with gs and Pr. However, weak correlations between ФPSII, LUE and photochemical reflectance index (PRI) suggest that selected light conditions were not optimal for red leaf lettuce.


Assuntos
Alface/efeitos da radiação , Luz , Clorofila/química , Análise por Conglomerados , Gases/química , Gases/metabolismo , Alface/crescimento & desenvolvimento , Fotossíntese/efeitos da radiação , Folhas de Planta/química , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/efeitos da radiação , Análise de Componente Principal , Teoria Quântica , Raios Ultravioleta
5.
Plant Sci ; 290: 110299, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31779902

RESUMO

Forest understory species have to acclimatize to highly heterogeneous light conditions inside forest canopies in order to utilize available resources efficiently. Light sensitivity and response speed of hydraulic conductance (KL) of common hazel (Corylus avellana L.) to fast changes in irradiance was studied in leaves from three different growth light conditions-sun-exposed, moderate shade, and deep shade. The KL of sun-exposed leaves was approximately 3-fold higher when compared to deep-shade leaves, indicating a strong dependence of leaf hydraulic capacity on light conditions. The KL of sun-exposed leaves increased by a factor of nearly four from minimal values recorded in darkness to maximal values in high light compared to deep-shade leaves. Reaction speed of KL to reach maximum values in response to light was nearly five times higher for sun-exposed vs deep-shade leaves. Plasticity indices of KL for sun-exposed and deep-shade leaves were 0.44 and 0.27, respectively. Higher light sensitivity enables a faster and more plastic response of KL to variable light conditions in sun leaves and enhances the ability of plants to maximize resource utilization under more beneficial environmental conditions.


Assuntos
Adaptação Fisiológica , Corylus/fisiologia , Folhas de Planta/fisiologia , Luz Solar , Transporte Biológico/fisiologia , Transporte Biológico/efeitos da radiação , Corylus/efeitos da radiação , Folhas de Planta/efeitos da radiação
6.
J Agric Food Chem ; 67(46): 12972-12985, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31709797

RESUMO

Controlling the temperature inside a greenhouse during the summer is a problem of increasing importance in the Mediterranean countries, especially in the Spanish southeast. The metabolic profile of greenhouse tomatoes and leaves grown under conventional conditions and within the presence of a shade mesh (∼50% reduction of sunlight radiation) has been monitored. Tomatoes were weekly harvested from May to July 2017 and analyzed by NMR spectroscopy coupled to multivariate data analysis techniques, together with oxygen radical absorbance capacity (ORAC) assays (for antioxidant activity). Fatty acids and carotenoids profiles were unraveled by GC-FID and HPLC-DAD, respectively. To verify whether it would be possible to take advantage of different light growing conditions to potentiate a plant's defense system, leaves of the corresponding plants were collected and their methanolic extracts were analyzed by NMR toward deciphering new biomarkers, which were used to assess their antibacterial and antibiofilm activities. The presence of a shading mesh resulted in a reduction in tomato production and in smaller fruits with lower contents of sugars (glucose and fructose) and carotenoids (lycopene and ß-carotene) and higher contents of organic acids, amino acids, and polyunsaturated fatty acids (linoleic and oleic acids) and of phenylpropanoids and flavonoids (which contributed to an increased antioxidant activity). Methanolic extracts of leaves of nonshaded plants showed a higher antibiofilm activity than that from shaded plants. This activity was well-correlated with an increase of phenolic compounds, together with some specific amino acids and organic acids from tomato leaves.


Assuntos
Frutas/química , Lycopersicon esculentum/efeitos da radiação , Folhas de Planta/química , Antioxidantes/metabolismo , Alimentos Orgânicos/análise , Alimentos Orgânicos/efeitos da radiação , Frutas/crescimento & desenvolvimento , Frutas/metabolismo , Frutas/efeitos da radiação , Lycopersicon esculentum/química , Lycopersicon esculentum/crescimento & desenvolvimento , Lycopersicon esculentum/metabolismo , Espectroscopia de Ressonância Magnética , Metaboloma/efeitos da radiação , Metabolômica , Valor Nutritivo/efeitos da radiação , Extratos Vegetais/química , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Folhas de Planta/efeitos da radiação , Luz Solar
7.
Plant Sci ; 287: 110169, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31481230

RESUMO

During the grain filling stage, high light (HL) usually results in premature leaf senescence and significant yield loss in wheat. To explore the responses of sugar metabolism and the association of sugar accumulation and leaf senescence in HL, the activity and gene expression of sugar metabolism-related enzymes were analyzed when two wheat cultivars Triticum aestivum L. Xiaoyan 54 (XY54, HL tolerant) and Jing 411 (J411, HL sensitive) were transferred from low light (LL) to HL for 28 d. The results showed that the CO2 assimilation rate, quantity of Rubisco and chlorophyll binding proteins decreased substantially for both cultivars in HL. However, the content of fructose, sucrose, and starch increased dramatically. In addition, the activity of hexokinase, pyruvate kinase, sucrose phosphate synthase, sucrose synthase, and alkaline/neutral invertase increased significantly while the expression of most of the sugar metabolism-related genes were repressed by long-term HL. Correlation analysis revealed that sugar content and sucrose phosphate synthase activity were negatively while the expression of most sugar metabolism-related genes were positively correlated with chlorophyll content during HL treatment. Comparatively, the HL tolerant cultivar XY54 accumulated less sugars than the HL sensitive cultivar J411, suggesting that sugar metabolism may be the regulation target for wheat improvement to cope with HL stress.


Assuntos
Folhas de Planta/metabolismo , Açúcares/metabolismo , Triticum/metabolismo , Envelhecimento , Luz , Fotossíntese , Folhas de Planta/química , Folhas de Planta/fisiologia , Folhas de Planta/efeitos da radiação , Açúcares/análise , Transcriptoma/efeitos da radiação , Triticum/química , Triticum/fisiologia , Triticum/efeitos da radiação
8.
Biochim Biophys Acta Bioenerg ; 1860(11): 148073, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31473302

RESUMO

Photosystem I (PSI) is a potential target of photoinhibition under fluctuating light. However, photosynthetic regulation under fluctuating light in field-grown plants is little known. Furthermore, it is unclear how young leaves protect PSI against fluctuating light under natural field conditions. In the present study, we examined chlorophyll fluorescence, P700 redox state and the electrochromic shift signal in the young and mature leaves of field-grown Cerasus cerasoides (Rosaceae). Within the first seconds after any increase in light intensity, young leaves showed higher proton gradient (ΔpH) across the thylakoid membranes than the mature leaves, preventing over-reduction of PSI in the young leaves. As a result, PSI was more tolerant to fluctuating light in the young leaves than in the mature leaves. Interestingly, after transition from low to high light, the activity of cyclic electron flow (CEF) in young leaves increased first to a high level and then decreased to a stable value, while this rapid stimulation of CEF was not observed in the mature leaves. Furthermore, the over-reduction of PSI significantly stimulated CEF in the young leaves but not in the mature leaves. Taken together, within the first seconds after any increase in illumination, the stimulation of CEF favors the rapid lumen acidification and optimizes the PSI redox state in the young leaves, protecting PSI against photoinhibition under fluctuating light in field-grown plants.


Assuntos
Luz , Fotossíntese/fisiologia , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/fisiologia , Prunus/crescimento & desenvolvimento , Prunus/fisiologia , Adaptação Fisiológica , Concentração de Íons de Hidrogênio , Oxirredução , Periodicidade , Fotossíntese/efeitos da radiação , Complexo de Proteína do Fotossistema I/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/efeitos da radiação , Prótons , Prunus/efeitos da radiação , Tilacoides/fisiologia , Tilacoides/efeitos da radiação
9.
Plant Cell Physiol ; 60(10): 2319-2330, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31268146

RESUMO

Fruit set is an important yield-related parameter, which varies drastically due to genetic and environmental factors. Here, two commercial cultivars of Capsicum chinense (Biquinho and Habanero) were evaluated in response to light intensity (unshaded and shaded) and N supply (deficiency and sufficiency) to understand the role of source strength on fruit set at the metabolic level. We assessed the metabolic balance of primary metabolites in source leaves during the flowering period. Furthermore, we investigated the metabolic balance of the same metabolites in flowers to gain more insights into their influence on fruit set. Genotype and N supply had a strong effect on fruit set and the levels of primary metabolites, whereas light intensity had a moderate effect. Higher fruit set was mainly related to the export of both sucrose and amino acids from source leaves to flowers. Additionally, starch turnover in source leaves, but not in flowers, had a central role on the sucrose supply to sink organs at night. In flowers, our results not only confirmed the role of the daily supply of carbohydrates on fruit set but also indicated a potential role of the balance of amino acids and malate.


Assuntos
Aminoácidos/metabolismo , Capsicum/fisiologia , Nitrogênio/metabolismo , Amido/metabolismo , Sacarose/metabolismo , Biomassa , Capsicum/genética , Capsicum/crescimento & desenvolvimento , Capsicum/efeitos da radiação , Flores/genética , Flores/crescimento & desenvolvimento , Flores/fisiologia , Flores/efeitos da radiação , Frutas/genética , Frutas/crescimento & desenvolvimento , Frutas/fisiologia , Frutas/efeitos da radiação , Genótipo , Luz , Malatos/metabolismo , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/fisiologia , Folhas de Planta/efeitos da radiação
10.
J Agric Food Chem ; 67(31): 8452-8458, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31294967

RESUMO

Insights into the environmental fates of nitrated polycyclic aromatic hydrocarbons (NPAHs) in edible vegetables are of great significance for better evaluating human exposure to NPAHs through the dietary pathway. In this work, a fluorescence quenching method using graphene quantum dots as a fluorescent probe was first applied for the in vivo determination of 9-nitroanthracene (9-NAnt) and 1-nitropyrene (1-NPyr) adsorbed on the leaf surfaces of living lettuce (Lactuca sativa L.) seedlings. Moreover, the photolysis kinetics and mechanisms of the two adsorbed NPAHs were discussed. The photodegradation kinetics followed the pseudo-first-order equation, and the photodegradation half-life of 1-NPyr (7.4 ± 0.2 h) was greater than that of 9-NAnt (2.3 ± 0.1 h). Anthraquinone and pyrenediones were identified to be the main photolytic products of 9-NAnt and 1-NPyr, respectively. Intramolecular rearrangement was the most reasonable mechanism for the NPAH photolysis. The photolysis-driven degradation exhibited a key role in scavenging NPAHs from the vegetable leaf, indicating the reduction of NPAH transportation in the food chain.


Assuntos
Alface/química , Nitratos/química , Folhas de Planta/química , Hidrocarbonetos Policíclicos Aromáticos/química , Poluentes Atmosféricos/química , Cinética , Alface/crescimento & desenvolvimento , Alface/efeitos da radiação , Fotólise/efeitos da radiação , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/efeitos da radiação , Plântula/química , Plântula/crescimento & desenvolvimento , Plântula/efeitos da radiação
11.
Plant Cell Physiol ; 60(10): 2307-2318, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31290959

RESUMO

Chlorophyll biosynthesis plays essential roles in photosynthesis and plant growth in response to environmental conditions. The accumulation of excess chlorophyll biosynthesis intermediates under light results in the production of reactive oxygen species and oxidative stress. In this study, we identified a rice (Oryza sativa) mutant, oxidation under photoperiod (oxp), that displayed photobleached lesions on its leaves, reduced growth and decreased chlorophyll content during light/dark cycles or following a dark-to-light transition. The oxp mutant accumulated more chlorophyll precursors (5-aminolevulinic acid and protochlorophyllide) than the wild type in the dark, and more singlet oxygen following light exposure. Several singlet-oxygen-responsive genes were greatly upregulated in oxp, whereas the expression patterns of OsPORA and OsPORB, two genes encoding the chlorophyll biosynthesis enzyme NADPH:protochlorop hyllide oxidoreductase, were altered in de-etiolated oxp seedlings. Molecular and complementation studies revealed that oxp is a loss-of-function mutant in LOC_Os01g32730, a homolog of FLUORESCENT (FLU) in Arabidopsis thaliana. Rice PHYTOCHROME-INTERACTING FACTOR-LIKE14 (OsPIL14) transcription factor directly bound to the OsFLU1 promoter and activated its expression. Dark-grown transgenic rice seedlings overexpressing OsPIL14 accumulated more chlorophyll and turned green faster than the wild type upon light illumination. Thus, OsFLU1 is an important regulator of chlorophyll biosynthesis in rice.


Assuntos
Proteínas de Arabidopsis/genética , Oryza/genética , Proteínas de Plantas/metabolismo , Transdução de Sinais/efeitos da radiação , Ácido Aminolevulínico/metabolismo , Clorofila/biossíntese , Estiolamento , Luz , Mutação , Oryza/fisiologia , Oryza/efeitos da radiação , Estresse Oxidativo , Fotoperíodo , Fotossíntese , Folhas de Planta/genética , Folhas de Planta/fisiologia , Folhas de Planta/efeitos da radiação , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas/genética , Protoclorifilida/metabolismo , Plântula/genética , Plântula/fisiologia , Plântula/efeitos da radiação , Oxigênio Singlete/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
12.
Int J Mol Sci ; 20(13)2019 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-31277435

RESUMO

High-intensity ultraviolet-B (UV-B) irradiation is a complex abiotic stressor resulting in excessive light exposure, heat, and dehydration, thereby affecting crop yields. In the present study, we identified quantitative trait loci (QTLs) for resistance to high-intensity UV-B irradiation in soybean (Glycine max [L.]). We used a genotyping-by-sequencing approach using an F6 recombinant inbred line (RIL) population derived from a cross between Cheongja 3 (UV-B sensitive) and Buseok (UV-B resistant). We evaluated the degree of leaf damage by high-intensity UV-B radiation in the RIL population and identified four QTLs, UVBR12-1, 6-1, 10-1, and 14-1, for UV-B stress resistance, together explaining 20% of the observed phenotypic variation. The genomic regions containing UVBR12-1 and UVBR6-1 and their syntenic blocks included other known biotic and abiotic stress-related QTLs. The QTL with the highest logarithm of odds (LOD) score of 3.76 was UVBR12-1 on Chromosome 12, containing two genes encoding spectrin beta chain, brain (SPTBN, Glyma.12g088600) and bZIP transcription factor21/TGACG motif-binding 9 (bZIP TF21/TGA9, Glyma.12g088700). Their amino acid sequences did not differ between the mapping parents, but both genes were significantly upregulated by UV-B stress in Buseok but not in Cheongja 3. Among five genes in UVBR6-1 on Chromosome 6, Glyma.06g319700 (encoding a leucine-rich repeat family protein) had two nonsynonymous single nucleotide polymorphisms differentiating the parental lines. Our findings offer powerful genetic resources for efficient and precise breeding programs aimed at developing resistant soybean cultivars to multiple stresses. Furthermore, functional validation of the candidate genes will improve our understanding of UV-B stress defense mechanisms.


Assuntos
Locos de Características Quantitativas/genética , Tolerância a Radiação/genética , Soja/genética , Soja/efeitos da radiação , Raios Ultravioleta , Mapeamento Cromossômico , Cromossomos de Plantas/genética , Cruzamentos Genéticos , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Ligação Genética , Genoma de Planta , Endogamia , Escore Lod , Fenótipo , Folhas de Planta/efeitos da radiação , Polimorfismo de Nucleotídeo Único/genética , Estresse Fisiológico/genética , Estresse Fisiológico/efeitos da radiação , Sintenia/genética
13.
Nutrients ; 11(7)2019 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-31277441

RESUMO

Vegetables, once harvested and stored on supermarket shelves, continue to perform biochemical adjustments due to their modular nature and their ability to retain physiological autonomy. They can live after being harvested. In particular, the content of some essential nutraceuticals, such as carotenoids, can be altered in response to environmental or internal stimuli. Therefore, in the present study, we wondered whether endogenous rhythms continue to operate in commercial vegetables and if so, whether vegetable nutritional quality could be altered by such cycles. Our experimental model consisted of rocket leaves entrained under light/darkness cycles of 12/12 h over 3 days, and then we examined free-run oscillations for 2 days under continuous light or continuous darkness, which led to chlorophyll and carotenoid oscillations in both constant conditions. Given the importance of preserving food quality, the existence of such internal rhythms during continuous conditions may open new research perspective in nutrition science. However, while chromatographic techniques employed to determine pigment composition are accurate, they are also time-consuming and expensive. Here we propose for the first time an alternative method to estimate pigment content and the nutritional quality by the use of non-destructive and in situ optical techniques. These results are promising for nutritional quality assessments.


Assuntos
Brassicaceae/metabolismo , Carotenoides/metabolismo , Clorofila A/metabolismo , Ritmo Circadiano , Armazenamento de Alimentos , Valor Nutritivo , Folhas de Planta/metabolismo , Verduras/metabolismo , Brassicaceae/efeitos da radiação , Carotenoides/efeitos da radiação , Clorofila A/efeitos da radiação , Ritmo Circadiano/efeitos da radiação , Embalagem de Alimentos , Fotoperíodo , Folhas de Planta/efeitos da radiação , Fatores de Tempo , Verduras/efeitos da radiação , Zeaxantinas/metabolismo
14.
Plant Cell Physiol ; 60(10): 2206-2219, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31271439

RESUMO

Photosynthetic induction, a gradual increase in photosynthetic rate on a transition from darkness or low light to high light, has ecological significance, impact on biomass accumulation in fluctuating light and relevance to photoprotection in strong light. However, the experimental quantification of the component electron fluxes in and around both photosystems during induction has been rare. Combining optimized chlorophyll fluorescence, the redox kinetics of P700 [primary electron donor in Photosystem I (PSI)] and membrane inlet mass spectrometry in the absence/presence of inhibitors/mediator, we partially estimated the components of electron fluxes in spinach leaf disks on transition from darkness to 1,000 �mol photons�m-2�s-1 for up to 10 min, obtaining the following findings: (i) the partitioning of energy between both photosystems did not change noticeably; (ii) in Photosystem II (PSII), the combined cyclic electron flow (CEF2) and charge recombination (CR2) to the ground state decreased gradually toward 0 in steady state; (iii) oxygen reduction by electrons from PSII, partly bypassing PSI, was small but measurable; (iv) cyclic electron flow around PSI (CEF1) peaked before becoming somewhat steady; (v) peak magnitudes of some of the electron fluxes, all probably photoprotective, were in the descending order: CEF1 > CEF2 + CR2 > chloroplast O2 uptake; and (vi) the chloroplast NADH dehydrogenase-like complex appeared to aid the antimycin A-sensitive CEF1. The results are important for fine-tuning in silico simulation of in vivo photosynthetic electron transport processes; such simulation is, in turn, necessary to probe partial processes in a complex network of interactions in response to environmental changes.


Assuntos
Transporte de Elétrons , Oxigênio/metabolismo , Fotossíntese/fisiologia , Complexo de Proteína do Fotossistema I/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Spinacia oleracea/fisiologia , Antimicina A/farmacologia , Dióxido de Carbono/metabolismo , Clorofila/metabolismo , Cloroplastos/metabolismo , Escuridão , Fluorescência , Cinética , Luz , Oxirredução , Folhas de Planta/fisiologia , Folhas de Planta/efeitos da radiação , Spinacia oleracea/efeitos da radiação
15.
J Photochem Photobiol B ; 197: 111550, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31330424

RESUMO

The plant species of the genus Epimedium L. are well-known traditional Chinese medicinal herbs with special therapeutic effects on human beings and animals in invigorating sexuality and strengthening muscles and bones. In large-scale cultivating Epimedium that is a typical shade plant species, they are arbitrarily covered with black colored shade nets. However, their optimal growth conditions, especially light, are still less understood. During the investigation of different light qualities on the growth of Epimedium pseudowushanense, it was found that, all the values of plant growth characteristics (except shoot number) and photosynthetic characteristics were lower under red, yellow, or blue light treatment than under white light treatment. However, yellow light treatment had beneficial effects on shoot number, dry biomass (per plant) as well as net photosynthesis rate (Pn) and maximal apparent quantum efficiency (AQY) in E. pseudowushanense when compared with red or blue light treatment. More importantly, we found that E. pseudowushanense accumulated higher levels of bioactive flavonoids under yellow light treatment than under white, red, or blue light treatment. Furthermore, both RNAseq and qPCR analyses revealed that yellow light could highly up-regulate the expression levels of flavonoid biosynthetic genes, in particular CHS1, F3H1, PT_5, and raGT_5 that possibly contributed to the enhanced accumulation of bioactive flavonoids in E. pseudowushanense. Taken together, our study revealed that yellow light is the optimal light for the growth of E. pseudowushanense. Our results provided key information on how to improve the cultivation condition and concurrently enhance the accumulation of bioactive flavonoids in E. pseudowushanense.


Assuntos
Epimedium/metabolismo , Flavonoides/metabolismo , Luz , Biomassa , Cromatografia Líquida de Alta Pressão , Medicamentos de Ervas Chinesas , Epimedium/crescimento & desenvolvimento , Epimedium/efeitos da radiação , Flavonoides/análise , Fotossíntese/efeitos da radiação , Folhas de Planta/metabolismo , Folhas de Planta/efeitos da radiação , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Brotos de Planta/metabolismo , Brotos de Planta/efeitos da radiação , RNA de Plantas/genética , RNA de Plantas/metabolismo , Análise de Sequência de RNA , Transcriptoma/efeitos da radiação
16.
Int J Mol Sci ; 20(14)2019 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-31340536

RESUMO

Molecular mechanisms that are the base of the strategies adopted by Mediterranean plants to cope with the challenges imposed by limited or excessive solar radiation during the summer season have received limited attention. In our study, conducted on C. incanus plants growing in the shade or in full sunlight, we performed measurements of relevant physiological traits, such as leaf water potential, gas exchange and PSII photochemistry, RNA-Seq with de-novo assembly, and the analysis of differentially expressed genes. We also identified and quantified photosynthetic pigments, abscisic acid, and flavonoids. Here, we show major mechanisms regulating light perception and signaling which, in turn, sustain the shade avoidance syndrome displayed by the 'sun loving' C. incanus. We offer clear evidence of the detrimental effects of excessive light on both the assembly and the stability of PSII, and the activation of a suite of both repair and effective antioxidant mechanisms in sun-adapted leaves. For instance, our study supports the view of major antioxidant functions of zeaxanthin in sunny plants concomitantly challenged by severe drought stress. Finally, our study confirms the multiple functions served by flavonoids, both flavonols and flavanols, in the adaptive mechanisms of plants to the environmental pressures associated to Mediterranean climate.


Assuntos
Adaptação Biológica/efeitos dos fármacos , Cistus/efeitos da radiação , Regulação da Expressão Gênica de Plantas , Complexo de Proteína do Fotossistema II/genética , Folhas de Planta/efeitos da radiação , RNA de Plantas/genética , Ácido Abscísico/metabolismo , Adaptação Biológica/genética , Antioxidantes/metabolismo , Clorofila/biossíntese , Cistus/genética , Cistus/metabolismo , Dano ao DNA , Reparo do DNA , DNA de Plantas/genética , DNA de Plantas/metabolismo , Flavonoides/biossíntese , Transdução de Sinal Luminoso/genética , Região do Mediterrâneo , Fotossíntese/genética , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/genética , Folhas de Planta/metabolismo , RNA de Plantas/metabolismo , Análise de Sequência de RNA , Energia Solar , Luz Solar , Água/metabolismo , Zeaxantinas/biossíntese
17.
J Photochem Photobiol B ; 197: 111549, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31302348

RESUMO

Light is a key factor influencing growth and development in plants. Specific irradiance and light quality can improve development and production of secondary compounds such as carotenoids during plant tissue culture. Bixin and norbixin, two apocarotenoids obtained from the seeds of Bixa orellana L. (annatto), are used as natural dyes in various industries. While annatto tissue culture has been successful, the effect of light in this species remains poorly understood. Here, we analyze for the first time the effect of irradiance regime (50, 150, 50 + 150, 200, 50 + 200 µmol m-2 s-1) and light spectral quality (fluorescent, white, blue/red LED) on in vitro development of apexes and bixin content in two contrasting bixin-producing varieties of B. orellana, namely 'Piave Vermelha' and 'UESB74'. The number of leaves per plant, stomatal density, leaf area, leaf expansion, chlorophylls and carotenoids content, malondialdehyde and bixin content were analyzed in the leaves of both cultivars. 'Piave Vermelha' produced 1.6-fold more bixin than 'UESB74'. Stomata cells of both cultivars had a paracytic arrangement with peltate trichomes along the adaxial and abaxial leaf surfaces. 'Piave Vermelha' preferred blue/red LED light; whereas fluorescent light was optimal for 'UESB74'. Under fluorescent light, an irradiance of 50 µmol m-2 s-1 is indicated for both cultivars. LED light increased bixin content only in 'Piave Vermelha', suggesting that the dye biosynthetic pathway is genotype-dependent. The present findings suggest the possibility of using light to modulate the bixin biosynthetic pathway.


Assuntos
Bixaceae/metabolismo , Carotenoides/análise , Luz , Bixaceae/efeitos da radiação , Carotenoides/metabolismo , Clorofila/análise , Fluorescência , Malondialdeído/análise , Folhas de Planta/metabolismo , Folhas de Planta/efeitos da radiação , Espectrometria de Massas por Ionização por Electrospray
18.
Zhongguo Zhong Yao Za Zhi ; 44(13): 2753-2761, 2019 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-31359687

RESUMO

Chlorophyll content,leaf mass to per area,net photosynthetic rate and bioactive ingredients of Asarum heterotropoides var. mandshuricum,a skiophyte grown in four levels of solar irradiance were measured and analyzed in order to investigate the response of photosynthetic capability to light irradiance and other environmental factors. It suggested that the leaf mass to per area of plant was greatest value of four kinds of light irradiance and decreasing intensity of solar irradiance resulted in the decrease of leaf mass to per area at every phenological stage. At expanding leaf stage,the rate of Chla and Chlb was 3. 11 when A. heterotropoides var. mandshuricum grew in full light irradiance which is similar to the rate of heliophytes,however,the rate of Chla and Chlb was below to 3. 0 when they grew in shading environment. The content of Chla,Chlb and Chl( a+b) was the greatest value of four kinds of light irradiance and decreasing intensity of solar irradiance resulted in its decreasing remarkably( P<0. 05). The rate of Chla and Chlb decreased but the content of Chla,Chlb and Chl( a+b) increased gradually with continued shading. The maximum value of photosynthetically active radiation appeared at 10: 00-12: 00 am in a day. The maximum value of net photosynthetic rate appeared at 8: 30-9: 00 am and the minimum value appeared at 14: 00-14: 30 pm at each phenological stage if plants grew in full sunlight. However,when plants grew in shading,the maximum value of net photosynthetic rate appeared at about 10: 30 am and the minimum value appeared at 12: 20-12: 50 pm at each phenological stage. At expanding leaf stage and flowering stage,the average of net photosynthetic rate of leaves in full sunlight was remarkably higher than those in shading and it decreased greatly with decreasing of irradiance gradually( P < 0. 05). However,at fruiting stage,the average of net photosynthetic rate of leaves in full sunlight was lower than those in 50% and 28% full sunlight but higher than those in 12% full sunlight. All photosynthetic diurnal variation parameters of plants measured in four kinds of different irradiance at three stages were used in correlation analysis. The results suggested that no significant correlation was observed between net photosynthetic rate and photosynthetically active radiation,and significant negative correlation was observed between net photosynthetic rate and environmental temperature as well as vapor pressure deficit expect for 12% full sunlight. Positive correlation was observed between net photosynthestic rate and relative humidity expect for 12% full sunlight. Significant positive correlation was observed between net photosynthetic rate and stomatal conductance in the four light treatments. Only,in 12% full sunlight,the net photosynthetic rate was significantly related to photosynthetically active radiation rather than related to environmental temperature,vapor pressure deficit and relative humidity. In each light treatment,a significant positive correlation was observed between environmental temperature and vapor pressure deficit,relative humidity as well as stomatal conductance. Volatile oil content was 1. 46%,2. 16%,1. 56%,1. 30% respectively. ethanol extracts was 23. 44%,22. 45%,22. 18%,21. 12% respectively. Asarinin content was 0. 281%,0. 291%,0. 279% and 0. 252% respectively. The characteristic components of Asarum volatile oil of plant in different light treatments did not change significantly among different groups.


Assuntos
Asarum/fisiologia , Asarum/efeitos da radiação , Fotossíntese , Luz Solar , Clorofila/análise , Folhas de Planta/efeitos da radiação
19.
J Sci Food Agric ; 99(14): 6608-6619, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31347167

RESUMO

BACKGROUND: Understanding plant responses to light quantity in indoor horticultural systems is important for optimising lettuce growth and metabolism as well as energy utilisation efficiency. Light intensity and photoperiod sufficient for normal plant growth parameters might be not efficient for nitrate assimilation. Therefore, this study explored and compared the effects of different light intensities (100-500 µmol m-2 s-1 ) and photoperiods (12-24 h) on the growth and nitrate assimilation in red and green leaf lettuce (Lactuca sativa L.). RESULTS: For efficient nitrate assimilation, 300-400 µmol m-2 s-1 photosynthetic photon flux density (PPFD) and 16-18 h photoperiod is necessary for red and green lettuces. The insufficient light quantity resulted in reduced growth and remarkable increase in nitrate and nitrite contents in both cultivars. Short photoperiods, similarly to low PPFD, growth parameters, chlorophyll indices and nitrate assimilation indices showed the shortage of photosynthetic products for normal plant physiological processes. Short photoperiods had the least pronounced effect on nitrate and nitrite contents in lettuce leaves. CONCLUSION: Light intensity was superior compared to photoperiods for efficient nitrate assimilation in both lettuce cultivars. Under short photoperiods, similarly to low intensity, growth parameters, chlorophyll index and nitrate assimilation indices showed a shortage of photosynthetic products for normal physiological processes. The free amino acid concentration increased, but it was not efficiently incorporated in proteins, as their level in lettuce was lower compared to those for moderate photoperiods. © 2019 Society of Chemical Industry.


Assuntos
Alface/metabolismo , Alface/efeitos da radiação , Nitratos/metabolismo , Clorofila/análise , Clorofila/metabolismo , Cor , Alface/química , Alface/crescimento & desenvolvimento , Luz , Nitratos/análise , Nitritos/análise , Nitritos/metabolismo , Fotoperíodo , Fotossíntese , Folhas de Planta/química , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Folhas de Planta/efeitos da radiação
20.
Plant Sci ; 286: 1-6, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31300135

RESUMO

The excessive and harmful light energy absorbed by the photosystem (PS) II of higher plants is dissipated as heat through a protective mechanism termed non-photochemical quenching (NPQ) of chlorophyll fluorescence. PsbS-knock-out (KO) mutants lack the trans-thylakoid proton gradient (ΔpH)-dependent part of NPQ. To elucidate the molecular mechanism of NPQ, we investigated its dependency on oxygen. The development of NPQ in wild-type (WT) rice under low-oxygen (LO) conditions was reduced to more than 50% of its original value. However, under high-oxygen (HO) conditions, the NPQ of both WT and PsbS-KO mutants recovered. Moreover, WT and PsbS-KO mutant leaves infiltrated with the ΔpH dissipating uncoupler nigericin showed increased NPQ values under HO conditions. The experiments using intact chloroplasts and protoplasts of Arabidopsis thaliana supported that the LO effects observed in rice leaves were not due to carbon dioxide deficiency. There was a noticeable 90% reduction in the half-time of P700 oxidation rate in LO-treated leaves compared with that of WT control leaves, but the HO treatment did not significantly change the half-time of P700 oxidation rate. Overall, the results obtained here indicate that the stroma of the PsbS-KO plants could be potentially under O2 deficiency. Because the functions of PsbS in rice leaves are likely to be similar to those in other higher plants, our findings offer novel insights into the role of oxygen in the development of NPQ.


Assuntos
Adaptação Fisiológica/efeitos da radiação , Arabidopsis/metabolismo , Oryza/metabolismo , Oxigênio/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Arabidopsis/efeitos da radiação , Cloroplastos/metabolismo , Cloroplastos/efeitos da radiação , Oryza/efeitos da radiação , Complexo de Proteína do Fotossistema II/genética , Folhas de Planta/genética , Folhas de Planta/fisiologia , Folhas de Planta/efeitos da radiação , Protoplastos/metabolismo , Protoplastos/efeitos da radiação
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