Changes in photosynthesis and antioxidant metabolism of cotton (Gossypium hirsutum L.) plants in response to manganese stress     

Renan Francisco Rimoldi Tavanti  Grace David Queiroz  Anne Caroline Da Rocha Silva  Walmor Moya Peres  Amanda Pereira Paixão  Fernando Shintate Galindo 《Archives of Agronomy and Soil Science》2020,66(6):743-762

ABSTRACT

This study aimed to assess the physiological and biochemical responses of cotton plants to manganese (Mn²⁺) nutrition. Four cotton genotypes (G1 – TMG 47; G2 – FM 975 WS; G3 – TMG 11 WS and G4 – IMA 8405 GLT) were grown in nutrient solution under two Mn²⁺ concentrations (2 and 200 µmol L^?1) for 10 days. No visible symptoms of Mn²⁺ toxicity were observed in the genotypes tested. All genotypes showed a marked increase in leaf chlorophylls, pheophytins, carotenoids, sucrose and total sugars concentration in response to high Mn²⁺ in a nutrient solution. However, the net photosynthetic rate, stomatal conductance, internal carbon dioxide concentration and transpiration decreased in genotypes G1 and G2 growing under 200 µmol L^?1. Antioxidant enzymes such as superoxide dismutase (SOD), ascorbate peroxidase (APX) and glutathione reductase (GR) activities increased in genotypes G1, G3 and G4. Cotton genotypes showed an increased leaf antioxidant and sugar metabolism as a possible strategy to mitigate oxidative stress. The decrease in the net photosynthetic rate and stomatal conductance; the increased antioxidant enzymes activities (SOD, APX and GR); and the increase in leaf sucrose and total sugar concentration were the main physiological and biochemical responses in cotton plants to Mn²⁺ stress.  相似文献   

Determination of Organic Mercury in Biota, Plants and Contaminated Sediments Using a Thermal Atomic Absorption Spectrometry Technique   总被引：1，自引：0，他引：1  

M. Válega  S. Abreu  P. Pato  L. Rocha  A. R. Gomes  M. E. Pereira  A. C. Duarte 《Water, air, and soil pollution》2006,174(1-4):223-234

A simple, rapid procedure for the determination of organic mercury in sediments, plants and fish tissues has been developed and validated. Extraction and separation of organic mercury compounds from the sample matrix was achieved by an established procedure based on an acid leaching of the sample (H₂SO₄/KBr/CuSO₄), followed by extraction of the organic mercury halide with toluene and back-extraction with an aqueous solution of thiosulphate. Detection and quantification of mercury, in the liquid extracts, was made by atomic absorption spectrometry (AAS), following thermal decomposition of the sample. The method was evaluated using Certified Reference Material (CRM) BCR 463 (tuna fish), BCR 580 (estuarine sediment), IAEA-140TM (sea plant homogenate) and NRCC TORT-2 (lobster hepathopancreas). The recovery factors for organic mercury in all tested CRM were between 81–107%. The precision of the method has relative standard deviations of less than 10% for sediments and fish tissues and of less than 16% for plant material. The method was successfully applied to natural samples of sediments, plants, macroalgae and fish tissues collected from an estuarine ecosystem and could, therefore, be used for routine analyses.  相似文献   

Production of Pearl Millet Irrigated with Different Levels of Brackish Water and Organic Matter     

Jaciele Beserra de Lira  Alberício Pereira de Andrade  André Luiz Rodrigues Magalhães  Fleming Sena Campos  Gherman Garcia Leal de Araújo  Diana Signor Deon 《Communications in Soil Science and Plant Analysis》2020,51(5):701-709

ABSTRACT

The objective is to determine the growth, yield and chemical characteristics of pearl millet irrigated with different levels of brackish water and organic matter in two cultivation cycles. The experimental design was randomized blocks in a 4 × 4 factorial arrangement, composed of 4 levels of brackish irrigation (25, 50, 75 and 100% evapotranspiration), 4 levels of organic matter (0, 15, 30 and 45 t ha^?1) with 3 repetitions. Along two cultivation cycles, pearl millet crop was analyzed for: plant growth variables, fresh and dry mass production, water-use efficiency, and chemical composition. There was significant interaction between applied water levels and organic matter for lignin in the 2nd cut (P < .05). The number of leaves, number of dead leaves and fresh mass production were influenced by the isolated effect of brackish water levels in cut 1 (P < .05). In turn, fresh mass production, dry mass production, plant height, leaves length, panicle length, fresh mass production, crude protein and ether extract were influenced by the isolated effect of saline water levels in the 2nd cut (P < .05). Growth, biomass production and chemical composition variables in second cut are positively influenced by different brackish irrigation levels under low rainfall conditions.  相似文献   

Application of high-temperature gas chromatography-mass spectrometry to the investigation of glycosidically bound components related to cashew apple (Anacardium occidentale L. Var. Nanum) volatiles     

Bicalho B  Pereira AS  Aquino Neto FR  Pinto AC  Rezende CM 《Journal of agricultural and food chemistry》2000,48(4):1167-1174

Free and bound volatile components of a Brazilian cashew apple variety (Anacardium occidentale L. var. nanum) were obtained by simultaneous distillation-extraction (SDE) and XAD-2 adsorption. According to gas chromatography-mass spectrometry (GC-MS) analyses and retention indices, 62 free volatile constituents were characterized and quantified. They were esters (40%), terpenes (20%), hydrocarbons (14%), fatty acids (9%), aldehydes (8%), alcohols (3%), lactones (3%), ketones (1%), phenols (1%), and norisoprenoids (1%). The glycosidically bound volatile precursors were analyzed by high-temperature GC-MS, after room temperature silylation. Several conjugated alcohols and cinnamic acids were detected and reported as cashew apple glycosyl constituents for the first time.  相似文献   

Rapid screening of polar compounds in Brazilian propolis by high-temperature high-resolution gas chromatography-mass spectrometry     

Pereira AS  Norsell M  Cardoso JN  Aquino Neto FR  Ramos MF 《Journal of agricultural and food chemistry》2000,48(11):5226-5230

Methanol extracts of propolis from six different places, five in Rio de Janeiro state and one in S?o Paulo state, both in the Southeast of Brazil, were investigated using high-temperature high-resolution gas chromatography (HT-HRGC) and HT-HRGC-mass spectometry. The main purpose of the study was to establish the applicability of HT-HRGC as an analytical method for systematic studies of polar propolis fractions. Several compounds, including carbohydrates, phenolic acid derivatives, and high molecular weight compounds (e.g., wax esters of long chain fatty alcohols) could be readily characterized in the crude extracts by HT-HRGC-MS. HT-HRGC and HT-HRGC-MS were shown to be quick and informative tools for rapid analysis of crude polar extracts without cleanup.  相似文献   

Transgenic fertile soybean plants derived from somatic embryos transformed via the combined DNA-free particle bombardment and <Emphasis Type="Italic">Agrobacterium</Emphasis> system     

Beatriz Wiebke-Strohm  Annette Droste  Giancarlo Pasquali  Marina Borges Osorio  Lauro Bücker-Neto  Luciane Maria Pereira Passaglia  Marta Bencke  Milena Schenkel Homrich  Márcia Margis-Pinheiro  Maria Helena Bodanese-Zanettini 《Euphytica》2011,177(3):343-354

An Agrobacterium-mediated transformation procedure for soybean [Glycine max L. Merrill] proliferating somatic embryos is here described. The Agrobacterium tumefaciens LBA4404 strain harboring pTOK233, pCAMBIA1390-olp or pH7WG2Dwrky plasmids was used to mediate gene transfer into the plant genome. Prior to Agrobacterium inoculation, proliferative soybean embryogenic clusters were microwounded by DNA-free tungsten particle bombardment. Three independent transformation experiments were performed. In Experiment I, 26 transgenic plants were obtained from a unique clone of cv Bragg, while 580 plants were recovered from 105 clones of cv IAS5. In Experiment II, a single hygromycin-resistant clone of cv BRSMG68 Vencedora was recovered and gave rise to five plants. In Experiment III, 19 plants of cv Bragg and 48 plants of IAS5 were recovered, representing five and 14 independent transformation events, respectively. PCR and Southern analyses confirmed the transgenes’ integration into plant genomes. Transgenic plants were fertile. They flowered, set pods and seeds. Transgene segregation in two T₁ progenies fits the Mendelian pattern (3:1 transgenic:non-transgenic plants). This is the first report of transgenic fertile soybean plants obtained from somatic embryogenic tissues transformed by the system that combines DNA-free particle bombardment and Agrobacterium.  相似文献   

ON THE EFFECTS OF VARIATION IN FREQUENCY OF STIMULATION ON STRIATED,CARDIAC AND SMOOTH MUSCLE     

Veach HO  Pereira JR 《Science (New York, N.Y.)》1924,60(1549):225-226

  相似文献   

TEMPERATURE AND MUSCULAR EXCITABILITY     

Pereira JR 《Science (New York, N.Y.)》1924,60(1544):102-103

  相似文献   

A developmentally regulated neuraminidase activity in Trypanosoma cruzi   总被引：18，自引：0，他引：18  

M E Pereira 《Science (New York, N.Y.)》1983,219(4591):1444-1446

The human pathogen Trypanosoma cruzi (Y strain) contains a neuraminidase activity that varies widely in the different developmental stages of the parasite. The specific neuraminidase activity of infective trypomastigotes obtained from tissue culture and from the bloodstream of infected mice is 7 to 15 times higher than that of the acellular culture forms. Amastigotes were devoid of enzyme activity. The enzyme has a pH optimum of 6.0 to 6.5. Live trypanosomes released sialic acid from human erythrocytes and plasma glycoproteins. Several sialyl compounds were hydrolyzed by the parasite, but the best substrate was the protein orosomucoid. Erythrocytes from infected mice with T. cruzi parasitemia were agglutinated by peanut lectin and the hemagglutination titer was correlated with the degree of parasitemia.  相似文献   

Synthetic clonal reproduction through seeds     

Marimuthu MP  Jolivet S  Ravi M  Pereira L  Davda JN  Cromer L  Wang L  Nogué F  Chan SW  Siddiqi I  Mercier R 《Science (New York, N.Y.)》2011,331(6019):876

Cloning through seeds has potential revolutionary applications in agriculture, because it would allow vigorous hybrids to be propagated indefinitely. However, asexual seed formation or apomixis, avoiding meiosis and fertilization, is not found in the major food crops. To develop de novo synthesis of apomixis, we crossed Arabidopsis MiMe and dyad mutants that produce diploid clonal gametes to a strain whose chromosomes are engineered to be eliminated after fertilization. Up to 34% of the progeny were clones of their parent, demonstrating the conversion of clonal female or male gametes into seeds. We also show that first-generation cloned plants can be cloned again. Clonal reproduction through seeds can therefore be achieved in a sexual plant by manipulating two to four conserved genes.  相似文献