Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 8.092
Filtrar
1.
Postepy Biochem ; 65(2): 128-134, 2019 06 06.
Artigo em Polonês | MEDLINE | ID: mdl-31642651

RESUMO

During leaf senescence and fruit ripening chlorophyll is broken down into nonfluorescent catabolites (NCCs). The chlorophyll degradation pathway includes a series of biochemical transformations ocurring sequentially in chloroplasts, cytosol and vacuoles. The path begins with enzymatic reduction of chlorophyll b to chlorophyll a. Next, the specific dechelatase and esterase remove the magnesium atom and the phytol chain resulting in the formation of pheophorbide a. In the next step, the porphyrin macroring is opened by pheophorbide a oxygenase and red catabolite reductase. The product of this transformation is an early fluorescent catabolite (pFCC), which after hydroxylation and species-specific modifications is imported into the vacuole. In acidic medium of the vacuole pFCC undergo isomerization to their respective colorless NCCs, which are final chlorophyll degradation products in higher plants. There are still no answers to a number of questions about the fate and significance of millions tons of chlorophyll catabolites released annually in the aquatic environment as a result of cellular senescence and death of phytoplankton. A few reports indicate that algae and cyanobacteria may metabolize their photosynthetic pigments in a similar way as higher plants do, however, the course of chlorophyll breakdown in these organisms has not been yet elucidated.


Assuntos
Clorofila/metabolismo , Células Vegetais/metabolismo , Oxirredutases/metabolismo , Células Vegetais/enzimologia , Folhas de Planta/enzimologia , Folhas de Planta/metabolismo
2.
J Agric Food Chem ; 67(39): 10813-10822, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31490069

RESUMO

Traditional seed pretreatment methods cause secondary pollution for the application of various chemicals. This study investigated the effect of dielectric barrier discharge (DBD) cold plasma on seedling growth. Effects of plasma-activated tap water (PATW) and plasma-activated seeds (PAS) were compared for germination rates, seedling height, dry weight, and chlorophyll content. Results show that compared with controls these growth parameters were all increased by more than 50%. The yields and contributions of hydrogen peroxide, nitrate, nitrite, and ammonium were quantified. Hydrogen peroxide and nitrate have an important role in seedling growth. By etching, the seed epidermis free radicals can reduce the apparent contact angle and increase the water absorption of the seeds. In addition to the low cost of PATW and PAS compared with commercial fertilizers, DBD does not involve any chemical addition. Thus, both PATW and PAS can be an alternative for improvement of agricultural production.


Assuntos
Produção Agrícola/métodos , Ervilhas/efeitos dos fármacos , Gases em Plasma/farmacologia , Sementes/crescimento & desenvolvimento , Compostos de Amônio/metabolismo , Clorofila/metabolismo , Produção Agrícola/instrumentação , Germinação/efeitos dos fármacos , Peróxido de Hidrogênio/metabolismo , Nitratos/metabolismo , Ervilhas/química , Ervilhas/crescimento & desenvolvimento , Ervilhas/metabolismo , Gases em Plasma/química , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Sementes/química , Sementes/efeitos dos fármacos , Sementes/metabolismo , Água/química
3.
J Agric Food Chem ; 67(42): 11607-11615, 2019 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-31560536

RESUMO

ζ-carotene desaturase (ZDS) is a key enzyme in carotenoid biosynthesis and plays an important role in plant photosynthesis. We characterized an albino leaf-color mutant obtained from ethyl methanesulfonate treatment: albino and seedling lethality 1 (ale1). The material contains a chloroplast thylakoid defect where photosynthetic pigments declined and reactive oxygen species accumulated resulting in ale1 death within 3 weeks. Positional cloning and sequencing revealed that there was a single base substitution in ALE1, which encoded a ZDS involved in carotenoid biosynthesis. RNAi and complementation tests confirmed the identity of ALE1. Subcellular localization showed that the ALE1 protein is localized in the chloroplast. Expression analysis indicated that the genes involved in chlorophyll and carotenoid biosynthesis were downregulated. We conclude that ALE1 plays an important role in chloroplast and plant growth in rice.


Assuntos
Cloroplastos/enzimologia , Oryza/crescimento & desenvolvimento , Oxirredutases/genética , Proteínas de Plantas/genética , Clorofila/metabolismo , Cloroplastos/genética , Regulação da Expressão Gênica de Plantas , Oryza/enzimologia , Oryza/genética , Oxirredutases/metabolismo , Fotossíntese , Proteínas de Plantas/metabolismo , Interferência de RNA , Plântula/enzimologia , Plântula/genética , Plântula/crescimento & desenvolvimento
4.
J Agric Food Chem ; 67(38): 10624-10636, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31483633

RESUMO

The freshness and color quality of postharvest tea leaves can be markedly prolonged and retained by proper preservation measures. Here, we investigated the dynamic changes of chlorophyll and its derivatives in postharvest tea leaves under different low-temperature treatments using natural withering as a control. Chlorophyll decomposition was found closely related with chlorophyllide, pheophorbide, and pheophytin. Low-temperature withering could slow chlorophyll degradation in postharvest tea leaves via significant inhibition on the enzyme activity and gene expression of Mg-dechelatase, chlorophyllase, and pheophorbide a oxygenase. At the initial stage of withering, a significant increase was observed in the chlorophyll content, expression of chlorophyll-synthesis-related enzymes (such as glutamyl-tRNA synthetase, etc.), and chlorophyll synthase activity in newly picked tea leaves. Moreover, an obvious decrease was found in the content of l-glutamate as the foremost precursor substance of chlorophyll synthesis. Hence, our findings revealed that the chlorophyll synthesis reaction was induced by the light-dehydration-stress in the initial withering of tea leaves. This study provides a theoretical basis for exploring preservation technology in actual green tea production.


Assuntos
Camellia sinensis/genética , Camellia sinensis/metabolismo , Clorofila/metabolismo , Manipulação de Alimentos/métodos , Regulação da Expressão Gênica de Plantas , Camellia sinensis/química , Camellia sinensis/crescimento & desenvolvimento , Hidrolases de Éster Carboxílico/genética , Hidrolases de Éster Carboxílico/metabolismo , Clorofila/química , Cor , Enzimas/genética , Enzimas/metabolismo , Oxigenases/genética , Oxigenases/metabolismo , Folhas de Planta/química , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Temperatura Ambiente
5.
Ying Yong Sheng Tai Xue Bao ; 30(9): 2941-2948, 2019 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-31529868

RESUMO

To explore the photosynthetic adaptation of Phoebe bournei to different light conditions, two-year-old P. bournei seedlings were grown under three light regimes (full light, shading rate 50% and 78% of full light). The chlorophyll contents, leaf gas exchange and chlorophyll fluorescence of P. bournei were measured after six-month treatment. The results showed that the contents of chlorophyll a, chlorophyll b, chlorophyll (a+b) and carotenoids in leaves were in a descending order of shading rate 78% > shading rate 50% > full light. There was no significant difference of chlorophyll a/b between natural and shade treatments. The shading treatment reduced light compensation point (LCP), but increased light saturation point (LSP) and apparent quantum yield (AQY), suggesting that plants could utilize both the weak light and the high light. Maximum net photosynthetic rate (Pn max), dark respiration rate (Rd), and maximum electron transfer rate (Jmax) increased under the shading treatment. There was significant difference between natural and shade treatment in net photosynthetic rate (Pn), stomatal conductance to CO2(gsc), intercellular CO2 concentration (Ci), and mesophyll conductance (gm). Pn and gm of different light regimes were sorted from the highest to the lowest as shading rate 78% > shading rate 50% > full light. gsc under shading rate 78% was higher than that under full light. Ci under shading rate 50% and 78% were lower than that under full light. Actual photochemical efficiency of PS2 (Fv'/Fm'), quantum yields of PS2 (ΦPS2), and electron transport rate (J) of P. bournei leaves were significantly higher under shading rate 78% than those under shading rate 50% and full light. In conclusion, P. bournei could increase Pn by increasing chlorophyll content, AQY, J, gsc, and gm under shade condition.


Assuntos
Clorofila/metabolismo , Lauraceae/fisiologia , Folhas de Planta/metabolismo , Clorofila/análise , Clorofila A , Fotossíntese/fisiologia , Folhas de Planta/química , Plântula , Luz Solar
6.
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
7.
Food Chem ; 299: 125163, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31319344

RESUMO

Citrus fruit postharvest degreening is a critical stage in marketing, carried out by exposure to ethylene or ethephon. Genome-wide screening of the AP2/ERF superfamily indicated that a novel ERF-II (CitERF6) was shown to trans-activate the CitPPH promoter. Expression of CitERF6 is associated with both developmental and postharvest degreening in citrus fruit. Transient and stable over-expression of CitERF6 in Nicotiana tabacum leaves and 'Ponkan' fruit also results in rapid chlorophyll degradation. Auto- and mutual-regulation was also found between CitERF6 and the previously characterized CitERF13 using the dual-luciferase and yeast one-hybrid assays. Moreover, substitution of the 35S promoter for endogenous promoters showed that both pCitERF6::CitERF6 and pCitERF13::CitERF13 were effective in trans-activating their promoters or triggering chlorophyll degradation. It is proposed that ethylene is one of the triggers activating promoters of CitERF6 and CitERF13, and subsequent auto- and mutual-regulation between CitERF6 and CitERF13 might facilitate the effect of ethylene, leading to fruit degreening.


Assuntos
Citrus/fisiologia , Etilenos/metabolismo , Frutas/fisiologia , Proteínas de Plantas/metabolismo , Clorofila/genética , Clorofila/metabolismo , Armazenamento de Alimentos , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas , Tabaco/genética
8.
Bioresour Technol ; 291: 121820, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31344639

RESUMO

Mixotrophy (M) assumes sum of autotrophic (A) and heterotrophic (H) growths. In this study, a novel split-mixotrophic cultivation strategy (SMCS) developed as better mixotrophy via offering mutual-benefits through gas-exchange at both headspaces while splitting both trophic modes. To quantify synergistic-growth effects in combined-autotrophy and combined-heterotrophy (CA&CH) of SMCS, gross O2-evolution, DIC and DO concentrations were compared with A, H and M. Average 12-14% and 26-32% increase in DIC and DO concentrations were determined respectively in CA and CH than A, H and M. Biomass yield in CA + CH was increased approx.1.5-folds higher than yields of A + H and M regimes. These results show SMCS as better cultivation strategy than the M by increased biomass and lipid yields. Challenges associated with organic carbon can be solved by SMCS viz. chlorophyll loss, organic carbon uptake inhibition. SMCS could be a breakthrough to integrate bacterial process with algae for better bioprocess economy and energy recovery.


Assuntos
Biomassa , Chlorella/metabolismo , Lipídeos/biossíntese , Processos Autotróficos , Chlorella/crescimento & desenvolvimento , Clorofila/metabolismo , Processos Heterotróficos
9.
BMC Plant Biol ; 19(1): 323, 2019 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-31319801

RESUMO

BACKGROUND: Exogenous 5-aminolevulinic acid (ALA) positively regulates plants chlorophyll synthesis and protects them against environmental stresses, although the protection mechanism is not fully clear. Here, we explored the effects of ALA on chlorophyll synthesis in tomato plants, which are sensitive to low temperature. We also examined the roles of the glutathione S-transferase (GSTU43) gene, which is involved in ALA-induced tolerance to oxidation stress and regulation of chlorophyll synthesis under low temperature. RESULTS: Exogenous ALA alleviated low temperature caused chlorophyll synthesis obstacle of uroporphyrinogen III (UROIII) conversion to protoporphyrin IX (Proto IX), and enhanced the production of chlorophyll and its precursors, including endogenous ALA, Proto IX, Mg-protoporphyrin IX (Mg-proto IX), and protochlorophyll (Pchl), under low temperature in tomato leaves. However, ALA did not regulate chlorophyll synthesis at the level of transcription. Notably, ALA up-regulated the GSTU43 gene and protein expression and increased GST activity. Silencing of GSTU43 with virus-induced gene silencing reduced the activities of GST, superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase, and increased the membrane lipid peroxidation; while fed with ALA significant increased all these antioxidase activities and antioxidant contents, and alleviated the membrane damage. CONCLUSIONS: ALA triggered GST activity encoded by GSTU43, and increased tomato tolerance to low temperature-induced oxidative stress, perhaps with the assistance of ascorbate- and/or a glutathione-regenerating cycles, and actively regulated the plant redox homeostasis. This latter effect reduced the degree of membrane lipid peroxidation, which was essential for the coordinated synthesis of chlorophyll.


Assuntos
Ácido Aminolevulínico/metabolismo , Clorofila/metabolismo , Genes de Plantas/fisiologia , Glutationa Transferase/metabolismo , Lycopersicon esculentum/genética , Proteínas de Plantas/metabolismo , Ácido Aminolevulínico/farmacologia , Resposta ao Choque Frio , Glutationa Transferase/genética , Homeostase/efeitos dos fármacos , Peroxidação de Lipídeos , Lycopersicon esculentum/efeitos dos fármacos , Lycopersicon esculentum/metabolismo , Lycopersicon esculentum/fisiologia , Oxirredução/efeitos dos fármacos , Proteínas de Plantas/genética
10.
BMC Plant Biol ; 19(1): 331, 2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31357955

RESUMO

BACKGROUND: Salt stress is one of the environmental factors that greatly limits crop production worldwide because high salt concentrations in the soil affect morphological responses and physiological and metabolic processes, including root morphology and photosynthetic characteristics. Soil aeration has been reported to accelerate the growth of plants and increase crop yield. The objective of this study was to examine the effects of 3 NaCl salinity levels (28, 74 and 120 mM) and 3 aeration volume levels (2.3, 4.6 and 7.0 L/pot) versus non-aeration and salinity treatments on the root morphology, photosynthetic characteristics and chlorophyll content of potted tomato plants. RESULTS: The results showed that both aeration volume and salinity level affected the root parameters, photosynthetic characteristics and chlorophyll content of potted tomato plants. The total length, surface area and volume of roots increased with the increase in aeration volume under each NaCl stress level. The effect was more marked in the fine roots (especially in ≤1 mm diameter roots). Under each NaCl stress level, the photosynthetic rate and chlorophyll content of tomato significantly increased in response to the aeration treatments. The net photosynthetic rate and chlorophyll a and t content increased by 39.6, 26.9, and 17.9%, respectively, at 7.0 L/pot aeration volume compared with no aeration in the 28 mM NaCl treatment. We also found that aeration could reduce the death rate of potted tomato plants under high salinity stress conditions (120 mM NaCl). CONCLUSIONS: The results suggest that the negative effect of NaCl stress can be offset by soil aeration. Soil aeration can promote root growth and increase the photosynthetic rate and chlorophyll content, thus promoting plant growth and reducing the plant death rate under NaCl stress conditions.


Assuntos
Lycopersicon esculentum/fisiologia , Fotossíntese , Raízes de Plantas/anatomia & histologia , Clorofila/metabolismo , Lycopersicon esculentum/anatomia & histologia , Lycopersicon esculentum/crescimento & desenvolvimento , Lycopersicon esculentum/metabolismo , Raízes de Plantas/fisiologia , Salinidade , Estresse Salino , Solo
11.
Plant Mol Biol ; 101(1-2): 183-202, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31286324

RESUMO

KEY MESSAGE: Isoforms of 2-OGDH E1 subunit are not functionally redundant in plant growth and development of A. thaliana. The tricarboxylic acid cycle enzyme 2-oxoglutarate dehydrogenase (2-OGDH) converts 2-oxoglutarate (2-OG) to succinyl-CoA concomitant with the reduction of NAD+. 2-OGDH has an essential role in plant metabolism, being both a limiting step during mitochondrial respiration as well as a key player in carbon-nitrogen interactions. In Arabidopsis thaliana two genes encode for E1 subunit of 2-OGDH but the physiological roles of each isoform remain unknown. Thus, in the present study we isolated Arabidopsis T-DNA insertion knockout mutant lines for each of the genes encoding the E1 subunit of 2-OGDH enzyme. All mutant plants exhibited substantial reduction in both respiration and CO2 assimilation rates. Furthermore, mutant lines exhibited reduced levels of chlorophylls and nitrate, increased levels of sucrose, malate and fumarate and minor changes in total protein and starch levels in leaves. Despite the similar metabolic phenotypes for the two E1 isoforms the reduction in the expression of each gene culminated in different responses in terms of plant growth and seed production indicating distinct roles for each isoform. Collectively, our results demonstrated the importance of the E1 subunit of 2-OGDH in both autotrophic and heterotrophic tissues and suggest that the two E1 isoforms are not functionally redundant in terms of plant growth in A. thaliana.


Assuntos
Arabidopsis/enzimologia , Carbono/metabolismo , Complexo Cetoglutarato Desidrogenase/metabolismo , Nitrogênio/metabolismo , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Dióxido de Carbono/metabolismo , Clorofila/metabolismo , Complexo Cetoglutarato Desidrogenase/genética , Mitocôndrias/enzimologia , Mutagênese Insercional , Nitratos/metabolismo , Fenótipo , Filogenia , Folhas de Planta/enzimologia , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Isoformas de Proteínas , Subunidades Proteicas , Plântula/enzimologia , Plântula/genética , Plântula/crescimento & desenvolvimento , Sementes/enzimologia , Sementes/genética , Sementes/crescimento & desenvolvimento
12.
Microbiol Res ; 226: 34-40, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31284942

RESUMO

Carotenoid composition has been studied in mesophilic, nitrogen-fixing cyanobacterium Anabaena sp. PCC7120 grown photoautotrophically, under diazotrophic conditions at four different temperatures (15 °C, 23 °C, 30 °C and 37 °C). The relative accumulation of chlorophyll, carotenoids and proteins was the highest at temperature of 23 °C. At a suboptimal temperature (15 °C) ß-carotene was the dominant carotenoid compound, whereas the increase in temperature caused ketocarotenoids (echinenone, canthaxanthin, keto-myxoxanthophyll) to accumulate. A significant increase in the accumulation of phytoene synthase (CrtB) transcript was observed at both extreme growth temperatures (15 °C and 37 °C). The relative amount of ß-carotene ketolase (CrtW) transcript directly corresponded to the accumulation of its product (keto-myxoxanthophyll) with a maximum at 30 °C and a profound decrease at 37 °C, whereas the transcription level of ß-carotene ketolase (CrtO) was significantly decreased only at a suboptimal temperature (15 °C). These results show that temperature affects the functioning of the carotenoid biosynthesis pathway in Anabaena cells under photoautotrophic growth. Specifically, the balance between ß-carotene and ketocarotenoids is altered according to temperature conditions. The transcriptional regulation of genes encoding enzymes active both at the early (CrtB) and the final steps (CrtO, CrtW) of the carotenoid biosynthetic pathway may participate in the acclimation mechanism of cyanobacteria to low and high temperatures.


Assuntos
Anabaena/crescimento & desenvolvimento , Anabaena/metabolismo , Carotenoides/biossíntese , Temperatura Ambiente , Anabaena/enzimologia , Anabaena/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Vias Biossintéticas/genética , Vias Biossintéticas/fisiologia , Cantaxantina , Clorofila/metabolismo , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos/genética , Geranil-Geranildifosfato Geranil-Geraniltransferase/genética , Geranil-Geranildifosfato Geranil-Geraniltransferase/metabolismo , Oxigenases/genética , Oxigenases/metabolismo , Estresse Fisiológico , beta Caroteno/biossíntese
13.
BMC Plant Biol ; 19(1): 324, 2019 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-31324149

RESUMO

BACKGROUND: Leaf shape development research is important because leaf shapes such as moderate curling can help to improve light energy utilization efficiency. Leaf growth and development includes initiation of the leaf primordia and polar differentiation of the proximal-distal, adaxial-abaxial, and centrolateral axes. Changes in leaf adaxial-abaxial polarity formation, auxin synthesis and signaling pathways, and development of sclerenchyma and cuticle can cause abnormal leaf shapes such as up-curling leaf. Although many genes related to leaf shape development have been reported, the detailed mechanism of leaf development is still unclear. Here, we report an up-curling leaf mutant plant from our Brassica napus germplasm. We studied its inheritance, mapped the up-curling leaf locus BnUC1, built near-isogenic lines for the Bnuc1 mutant, and evaluated the effect of the dominant leaf curl locus on leaf photosynthetic efficiency and agronomic traits. RESULTS: The up-curling trait was controlled by one dominant locus in a progeny population derived from NJAU5734 and Zhongshuang 11 (ZS11). This BnUC1 locus was mapped in an interval of 2732.549 kb on the A05 chromosome of B. napus using Illumina Brassica 60 K Bead Chip Array. To fine map BnUC1, we designed 201 simple sequence repeat (SSR) primers covering the mapping interval. Among them, 16 polymorphic primers that narrowed the mapping interval to 54.8 kb were detected using a BC6F2 family population with 654 individuals. We found six annotated genes in the mapping interval using the B. napus reference genome, including BnaA05g18250D and BnaA05g18290D, which bioinformatics and gene expression analyses predicted may be responsible for leaf up-curling. The up-curling leaf trait had negative effects on the agronomic traits of 30 randomly selected individuals from the BC6F2 population. The near-isogenic line of the up-curling leaf (ZS11-UC1) was constructed to evaluate the effect of BnUC1 on photosynthetic efficiency. The results indicated that the up-curling leaf trait locus was beneficial to improve the photosynthetic efficiency. CONCLUSIONS: An up-curling leaf mutant Bnuc1 was controlled by one dominant locus BnUC1. This locus had positive effects on photosynthetic efficiency, negative effects on some agronomic traits, and may help to increase planting density in B. napus.


Assuntos
Brassica napus/genética , Genes de Plantas/genética , Folhas de Planta/anatomia & histologia , Brassica napus/anatomia & histologia , Clorofila/metabolismo , Mapeamento Cromossômico , Genes de Plantas/fisiologia , Loci Gênicos , Mutação , Fotossíntese , Reação em Cadeia da Polimerase em Tempo Real
14.
Food Chem ; 298: 125017, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31260967

RESUMO

The aim of the study was to evaluate an elevated (3.0 °C) and low (1.0 °C) storage temperature combined with dynamic controlled atmosphere monitored by respiratory quotient (DCA-RQ) and chlorophyll fluorescence (DCA-CF) on anaerobic metabolism, physiological storage disorders and overall quality of 'Nicoter' ('Kanzi®') apples after 5.5 and 8.0 months of storage plus 7d shelf-life. Fruit stored under DCA-RQ 2.0 accumulated the highest amounts of anaerobic metabolites (acetaldehyde, ethanol and ethyl acetate), regardless of storage temperature and timing of storage outturn evaluation, but it did not result in higher electrolyte leakage. Flesh breakdown, core breakdown and cavity formation were reduced at 3 °C. Storage at 3 °C combined with DCA maintained higher flesh firmness after 8.0 months storage plus 7d shelf-life. 'Nicoter' apples can be stored at 3 °C using a DCA system, based either on CF or on RQ, to save electrical energy.


Assuntos
Armazenamento de Alimentos/métodos , Frutas/metabolismo , Malus/metabolismo , Acetaldeído/metabolismo , Acetatos/metabolismo , Anaerobiose , Atmosfera , Clorofila/metabolismo , Etanol/metabolismo , Fluorescência , Temperatura Ambiente
15.
Plant Physiol Biochem ; 141: 154-163, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31163342

RESUMO

Different nitrogen (N) sources have been reported to significantly affect the photosynthesis (Pn) and its attributes. However, molybdenum (Mo) induced effects on photosynthetic efficacy of winter wheat under different N sources have not been investigated. A hydroponic study was carried out comprising of two winter wheat cultivars '97003' and '97014' as Mo-efficient and Mo-inefficient, respectively to underpin the effects of Mo supply (0 and 1 µM) on photosynthetic efficacy of winter wheat under different N sources (NO3̶, NH4NO3 or NH4+). The results revealed that Mo-induced increases in dry weight, gas exchange parameters, chlorophyll contents, NR activities, NO3̶ assimilation, total N contents and transcripts of TaNR and TaNRT1.1 genes under different N sources followed the trend of NH4NO3 > NO3̶ > NH4+, suggesting that Mo has more complementary effects to nitrate nutrition than sole ammonium. Interestingly, under Mo-deprivation environments, cultivar '97003' recorded more pronounced alterations in Mo-dependent parameters than '97014' cultivar. Moreover, Mo application significantly improved the chlorophyll contents and chloroplast configuration in all N sources showing that Mo has a key role in chlorophyll biosynthesis and chloroplast integrity. The results also highlighted that Mo-induced enhancements in total N contents and photosynthetic characteristics followed the same order as NH4NO3 > NO3- > NH4+, suggesting that Mo might affect Pn through N metabolism. In crux, our study findings imply that Mo supply increased Pn not only through chlorophyll synthesis and chloroplast configuration but also by N uptake and assimilation which may represent a strategy of Mo fertilizer to strengthen the photosynthetic machinery.


Assuntos
Compostos de Amônio/metabolismo , Molibdênio/farmacologia , Nitrogênio/metabolismo , Fotossíntese/efeitos dos fármacos , Triticum/fisiologia , Clorofila/metabolismo , Cloroplastos/metabolismo , Fertilizantes , Hidroponia , Microscopia Eletrônica de Transmissão , Nitratos/metabolismo , Proteínas de Plantas/metabolismo , Triticum/efeitos dos fármacos
16.
Food Chem ; 297: 124964, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253313

RESUMO

Broccoli undergoes yellowing in unfavorable conditions, thereby diminishing the sensory quality and commodity value. This study aimed to investigate systematically cellular and/or biomolecular changes involved in broccoli yellowing by analyzing changes in microstructural integrity, pigment content, and gene expression. On day-5 of storage at 20 °C, the buds turned yellow without blooming and showed structural damage; ultrastructural analysis revealed plastid transformation and abnormal chloroplast development. Genes regulating pigment content and chloroplast structure directly were identified. More specifically, BoCAO and BoNYC1 regulated chlorophyll turnover, affecting chlorophyll a and b contents. Changes in the ß-cryptoxanthin content were influenced by the combined action of up- (BoHYD) and downstream (BoZEP) genes. BoZEP and BoVDE were activated after cold-temperature induction. High BoHO1 expression delayed yellowing at low temperature, inducing BoZEP expression. Color intensity correlated significantly with the chlorophyll b, ß-cryptoxanthin, and ß-carotene contents, which were associated with increased yellowing of plant tissues.


Assuntos
Brassica/fisiologia , Carotenoides/metabolismo , Clorofila/metabolismo , Armazenamento de Alimentos , beta-Criptoxantina/genética , beta-Criptoxantina/metabolismo , Vias Biossintéticas , Brassica/ultraestrutura , Cloroplastos/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plastídeos/genética , Plastídeos/metabolismo , Temperatura Ambiente
17.
Ecotoxicol Environ Saf ; 182: 109379, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31254852

RESUMO

Chromium (Cr) contamination of soil and water has become a severe threat to human health. In this study, a series of experiments were conducted to examine the ameliorative effects of Cr toxicity, by exogenous 100 µM sodium sulfate. Our team has examined the plant growth, Cr content, chlorophyll, antioxidant index and soluble protein content, before and after the addition of sodium sulfate. The results showed that the addition of sulfur (S) can reduce the enrichment of Cr and the content of malonyldialdehyde (MDA) under Cr stress. After addition of S in the culture solution, the biomass and roots length of Arabidopsis thaliana increased under Cr stress. Furthermore, the content of chlorophyll, superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), glutathione (GSH), and soluble protein increased with the addition of sulfur. Transmission electron microscope observation point to that the chloroplasts can be damaged in leaf. All data demonstrate that S supplementation should help to alleviate the negative effects caused by both Cr(III) and Cr(VI) on Arabidopsis thaliana.


Assuntos
Antioxidantes/metabolismo , Arabidopsis/efeitos dos fármacos , Cromo/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Poluentes do Solo/toxicidade , Sulfatos/farmacologia , Arabidopsis/metabolismo , Clorofila/metabolismo , Malondialdeído/metabolismo , Modelos Teóricos
18.
Ecotoxicol Environ Saf ; 182: 109378, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31254855

RESUMO

Recently, the strategy of seed soaking has been successfully applied using extracts from different plant parts for healthy growth of plant under different environmental stresses. Compared to antioxidants like ascorbic acid (AsA) and glutathione (GSH) or polyamines (PAs) like spermine (SPM), spermidine (SPD), and putrescine (PUT), the effects of seed soaking using maize grain extract (MGE) on the biomass, productivity, phytohormones, and antioxidant defense system and its different components were examined with Cd2+-stressed wheat plants. In a preliminary study, seed soaking using AsA + GSH or PUT + SPD + SPM was more effective in increasing shoot fresh and dry weights, SPAD chlorophyll, and grain yield, and reducing malondialdehyde (MDA) content than individuals. In addition, MGE at 2% was more efficient than other concentrations. Therefore, they were selected for the main study. In the main study, compared to the control, seed soaking in AsA + GSH, PUT + SPD + SPM or MGE had positive effects on plant growth, yield, photosynthetic efficiency, contents and redox states of AsA and GSH, contents of PAs and plant hormones to varying degrees. Proline content and its metabolism enzymes activity, contents of soluble protein, N-compounds, soluble sugars, and α-tocopherol (α-TOC), and activities of antioxidant enzymes were not affected. However, contents of MDA and hydrogen peroxide (H2O2) were significantly reduced under normal conditions. Under Cd2+ stress (1.2 mM), along with the detrimental increases in the contents of MDA, H2O2 and Cd2+, contents of N-compounds, soluble sugars, proline content and its metabolism enzymes activities, AsA and GSH and their redox states, and polyamines, and activities of antioxidant enzymes were increased. In contrast, plant growth and yield, photosynthetic efficiency, soluble protein, and plant hormones were significantly reduced compared to the control. However, all of these attributes were significantly improved to varying degrees along with reduced contents of Cd2+, MDA, and H2O2 by seed soaking in AsA + GSH, PUT + SPD + SPM or MGE compared to the Cd2+-stressed control. Compared to AsA + GSH or PUT + SPD + SPM, seed soaking in MGE at 2% conferred the best results. Therefore, it is recommended to soak wheat seeds using MGE to improve plant growth and productivity by restricting the inhibitory influences of oxidative stress induced by Cd2+ stress.


Assuntos
Antioxidantes/farmacologia , Cádmio/toxicidade , Extratos Vegetais/farmacologia , Poliaminas/farmacologia , Poluentes do Solo/toxicidade , Triticum/efeitos dos fármacos , Zea mays/química , Antioxidantes/metabolismo , Clorofila/metabolismo , Grão Comestível/efeitos dos fármacos , Grão Comestível/metabolismo , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Extratos Vegetais/isolamento & purificação , Poliaminas/metabolismo , Triticum/metabolismo
19.
Plant Sci ; 285: 44-54, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31203893

RESUMO

Although the involvement of ROS (reactive oxygen species) in leaf senescence is well known, the factors governing this accumulation of ROS are not fully characterized. In this study, analysis of transgenic overexpressing and knock out lines of AtWDS1 (encoding a WD repeat protein), indicates that AtWDS1 negatively regulates age-dependent and dark-induced leaf senescence. Furthermore, we observed ROS accumulation and altered tolerance of oxidative stress in atwds1 plants, as well as upregulated expression of oxidative stress-responsive genes. The location of an EGFP-AtWDS1 fusion protein in the nucleus of transformed cells and plants indicates that AtWDS1 is a nuclear protein, and, using a Dual-Luciferase assay, we showed that AtWDS1 can act as a transcription activator. However, the lack of a nuclear localization sequence in AtWDS1 suggests that its presence in the nucleus must depend on interactions with other proteins. Indeed, we found that AtWDS1 interacts directly with AtRanBPM, and that mutation of the AtRanBPM gene results in partial mislocalization of AtWDS1 in the cytoplasm. Together, these results suggest a role for AtWDS1 as a novel modulator of redox homeostasis, which responds to developmental and stress signals to regulate leaf senescence.


Assuntos
Proteínas de Arabidopsis/fisiologia , Arabidopsis/crescimento & desenvolvimento , Peptídeos e Proteínas de Sinalização Intracelular/fisiologia , Folhas de Planta/crescimento & desenvolvimento , Arabidopsis/fisiologia , Clorofila/metabolismo , Escuridão , Microscopia Confocal , Folhas de Planta/fisiologia , Protoplastos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transcriptoma
20.
Environ Pollut ; 252(Pt B): 1087-1096, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31252106

RESUMO

Effects of CeO2 NPs (200 mg.L-1) on rice (Oryza sativa L.) alone or co-exposure with cadmium (Cd) and salt (sodium chloride, NaCl) were investigated in hydroponic systems for two weeks. Physiological results show that rice biomass was significantly inhibited when NaCl or CdCl2 added alone or in co-exposure treatment. CeO2 NPs significantly relieve the chlorophyll damage under CdCl2 environmental stress. The presence of CeO2 NPs alleviated both stressors induced damages to rice as indicated by the reduced proline level. Additionally, CeO2 NPs triggered the antioxidant defense systems to counteract the oxidative stress caused by NaCl and CdCl2. The level of 8-OHdG, one of the most important indicators for genotoxicity, in rice suggest that the presence of CeO2 NPs reduced the DNA damage in NaCl treated rice. Elemental analysis indicated that co-exposure to NaCl and CdCl2 slightly decreased the Cd content as compared to the one in the CdCl2 alone treatment, and this co-exposure also significantly reduced the Na content when comparing with the NaCl alone treatment. Taken together, our findings suggest that CeO2 NPs could alleviate the CdCl2 and NaCl stresses, but could not completely change the phenotype of both contaminants treated rice.


Assuntos
Cádmio/toxicidade , Cério/farmacologia , Nanopartículas/química , Oryza/efeitos dos fármacos , Cloreto de Sódio/toxicidade , Poluentes do Solo/toxicidade , Antioxidantes/farmacologia , Biomassa , Cério/química , Clorofila/metabolismo , Hidroponia , Oryza/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Plântula/efeitos dos fármacos , Plântula/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA