Genetic variation and environmental effects on beta-conglycinin and glycinin content in Brazilian soybean cultivars

The objective of this work was to determine genetic and environmental effects on beta-conglycinin and glycinin content in Brazilian soybean cultivars. The concentrations of these protein fractions were analyzed by scanning densitometry after electrophoresis, in 90 Brazilian soybean cultivars sown in Ponta Grossa, PR, in 2001. The effects of the sowing location were determined in the cultivar MG/BR 46 (Conquista), sown in 16 locations of Goiás and Minas Gerais states (Central Brazil), and in the cultivar IAS 5, sown in 12 locations of Paraná and São Paulo states (Southern Brazil), in 2002 soybean season. A significant variability for beta-conglycinin (7S) and glycinin (11S) protein fractions ratio was observed among the 90 Brazilian soybean cultivars. 'MS/BRS 169' (Bacuri) and 'BR-8' (Pelotas) presented the highest and the lowest 11S/7S ratios (2.76 and 1.17, respectively). Beta-conglycinin protein fractions presented more variability than glycinin protein fractions. Grouping test classified 7S proteins in seven groups, 11S proteins in four groups, and protein fraction ratios (11S/7S) in nine groups. Significant effect of sowing locations was also observed on protein fractions contents. There is a good possibility of breeding for individual protein fractions, and their subunits, without affecting protein content.

Environmental and genetic variation of isoflavone content of soybean seeds grown in Brazil

The objective of this work was to evaluate isoflavone concentrations in seeds of different Brazilian soybean cultivars grown in a range of locations and environmental conditions in Brazil. Seeds of 233 cultivars grown in Ponta Grossa, PR, Brazil, during the 2001/2002 soybean season, and of 22 cultivars sown in different locations of Brazilian Northeast, Southeast on South regions were analyzed for total isoflavones, including daidzin, glycitin, genistin and acetylgenistin. The total isoflavones ranged from 12 mg 100 g-1 (cv. Embrapa 48) to 461 mg 100 g-1 (cv. CS 305) among the 233 cultivars grown in Ponta Grossa, and the differences among them are due to genetic effects since all cultivars were grown and collected at the same locatation and year. This is an indication of the possibility of breeding for isoflavone content. Differences in isoflavone content observed in the cultivars grown in different locations permit the selection of locations for optimum isoflavone content (low or high), depending on the uses of soybean. In the Northeast region (5-8°S), higher concentrations of total isoflavones were observed at São Raimundo das Mangabeiras (232 mg 100 g-1) and Tasso Fragoso (284 mg 100 g-1) municipalities, and in the South (23-30°S), isoflavones were higher in Guarapuava, Canoinhas, Vacaria and Campos Novos municipalities, ranging from 130 to 409 mg 100 g-1.

Prediction of direct and indirect genetic gains and genotypic correlations in rubber tree progenies

The objective of this work was to estimate the genetic parameters, genotypic and phenotypic correlations, and direct and indirect genetic gains among and within rubber tree (Hevea brasiliensis) progenies. The experiment was set up at the Municipality of Jaú, SP, Brazil. A randomized complete block design was used, with 22 treatments (progenies), 6 replicates, and 10 plants per plot at a spacing of 3x3 m. Three‑year‑old progenies were assessed for girth, rubber yield, and bark thickness by direct and indirect gains and genotypic correlations. The number of latex vessel rings showed the best correlations, correlating positively and significantly with girth and bark thickness. Selection gains among progenies were greater than within progeny for all the variables analyzed. Total gains obtained were high, especially for girth increase and rubber yield, which were 93.38 and 105.95%, respectively. Young progeny selection can maximize the expected genetic gains, reducing the rubber tree selection cycle.

Seasonal variation in the composition of volatile oils from Schinus terebinthifolius raddi

Essential oils from leaves, ripe and unripe fruits of Schinus terebinthifolius growing in Brazil were investigated. Oil content from either ripe or unripe fruits was similar (4.65% and 3.98%, respectively). Sesquiterpenes (from 78.0% to 90.4%) dominated the oil content of both leaves and unripe fruit. The essential oils were tested in vitro for their allelopathic activity on germination and radicle growth of Lactuca sativa and Cucumis sativus at 1,000 and 10,000 µg mL-1concentrations. The three samples tested were more active in inhibiting the radicle growth for L. sativa (88.6-92.4%) than for C. sativus (50.5-84.5%) at 10,000 µg mL-1 concentration.

Interespecific variation in the composition of volatile oils from the leaves of Swietenia macrophylla King (Meliaceae)

The volatile oils from leaves of five Brazilian specimens of Swietenia macrophylla King (Meliaceae) collected in three different Amazon Rainforest Conservation Areas in the States of Mato Grosso, Pará, and Rondônia were extracted and analyzed by GC and GC/MS. The oils showed to be composed by terpenoids, majority hydrocarbon sesquiterpenes, being germacrene D (20.5-46.8%) and bicyclogermacrene (8.3-11.1%) the main components. Besides these derivatives, only α-cubebene, β-caryophyllene, β-gurjunene and γ-cadinene were detected in all of the analyzed samples. This analysis indicated a great diversity of constituents in the oils obtained from specimens collected in these regions, which could be associated to the different susceptibility in the attack of H. grandella in S. macrophylla cultures.

Seasonal variation of the major secondary metabolites present in the extract of Eremanthus mattogrossensis Less (Asteraceae: Vernonieae) leaves

The species Eremanthus mattogrossensis, known as "veludo do cerrado" (cerrado velvet), is native to the Brazilian Cerrado. Because the amount of metabolites present in plants may be influenced by biological and environmental factors, here we conducted an HPLC-DAD-MS/MS investigation of the metabolite concentrations found in the MeOH/H2O extract of the leaves of this species. The main compounds were identified and quantified, and the metabolites were grouped by chemical class (caffeoylquinic acids, flavonoids, and sesquiterpene lactone). Statistical analysis indicated a straight correlation between the quantity of metabolites and seasonality, suggesting that environmental properties elicit important metabolic responses.

Variation of essential oil composition of Tapirira guianensis Aubl. (Anacardiaceae) from two sandbank forests, north of Brazil

Tapirira guianensis (Anacardiaceae) is used in traditional medicine and is important for the recovery of degraded areas and riparian forests because the T. guianensis fruits are highly consumed by wildlife. Volatile components from dried leaves and branches of five individual plants of T. guianensis were collected in two sandbank forests of the State of Pará (Extractive Reserve Maracanã and Area of Environmental Protection Algodoal/Maiandeua), extracted by hydrodistillation using a Clevenger-type apparatus, and analyzed by GC/MS. The ten oils obtained are comprised mostly of sesquiterpene hydrocarbons (58.49 to 100%), with (E)-caryophyllene, β-selinene, α-selinene, β-sesquiphellandrene, and α-zingiberene being the most prominent. The results of the oil compositions were processed by Hierarchical Component Analysis (HCA) allowing the establishment of three groups of essential oils for T. guianensis differentiated by the content of β-selinene/α-selinene (Type I), (E)-caryophyllene (Type II), and β-sesquiphellandrene/α-zingiberene (Type III).

Genetic variation among pathogens causing "Helminthosporium" diseases of rice, maize and wheat

Twenty isolates of four fungal species, agents of "Helminthosporium" diseases in cereals, were collected from different regions: nine Bipolarisoryzae isolated from rice (Oryza sativa), seven B.sorokiniana from wheat (Triticum aestivum), two B. maydis, and two Exserohilumturcicum from maize (Zea mays). The strains were compared by PCR-RFLP and RAPD analysis. Size polymorphism among the isolates in the ITS region comprising the 5.8 S rDNA indicated genetic differences among the isolates, while a UPGMA phenogram constructed after the digestion of this region with restriction enzymes showed inter- and intra-specific polymorphism. The RAPD profiles indicated an expressive level of polymorphism among different species, compared with a low level of polymorphism among isolates of the same species. A UPGMA phenogram grouped the isolates according to the species and their host plant. RAPD profiles did not reveal polymorphism that directly correlated climatic factors with geographic source of the isolates of B. sorokiniana, and B. oryzae. Teleomorphic species revealed high similarity with their correspondent anamorphs.

Pathogenicity, molecular characterization, and cercosporin content of Brazilian isolates of Cercospora kikuchii

Cercospora kikuchii, involved with the defoliation of soybean (Glycine max) plants, is normally associated with Septoria glycines in late season. Seventy-two isolates from different regions in Brazil, obtained mainly from purple stained seeds, showed phenotypic variation. Cercosporin content and rate of colony growth was higly variable among isolates. A strong correlation between cercosporin content and virulence was identified. Genetic variation among and within populations was evaluated based on 86 RAPD loci. The RAPD analysis clustered all isolates into seven groups. No relationship was observed between RAPD groups and geographic origin or cercosporin content. The sequence of the internal spacer regions (ITS1-5.8S-ITS2) from 13 isolates chosen according to the previous RAPD and clustering analysis showed high similarity (97%-100%) to the GenBank sequences of C. kikuchii (AY266160, AY266161, AY152577 and AF291708). It is clear from this work that Brazilian isolates of C. kikuchii from different geographic regions, are variable in relation to virulence, RAPD profiles and cercosporin content. Cercosporin content could be a good parameter for choosing an adequate isolate for screening resistant or tolerant cultivars. Considering that this pathogen is easily seed-borne, findings are expected to show the same haplotypes in different regions. Migration could be favoured by infected seeds as demonstrated by RAPD analysis.

Immersion enthalpy variation of surface-modified mineral activated carbon in lead (II) aqueous solution adsorption: the relation between immersion enthalpy and adsorption capacity

An activated carbon was obtained by chemical activation with phosphoric acid, CM, from a mineral carbon. Afterwards, the carbon was modified with 2 and 5 molL-1, CMox2 and CMox5 nitric acid solutions to increase the surface acid group contents. Immersion enthalpy at pH 4 values and Pb2+ adsorption isotherms were determined by immersing activated carbons in aqueous solution. The surface area values of the adsorbents and total pore volume were approximately 560 m².g-1 and 0.36 cm³g-1, respectively. As regards chemical characteristics, activated carbons had higher acid sites content, 0.92-2.42 meq g-1, than basic sites, 0.63-0.12 meq g-1. pH values were between 7.4 and 4.5 at the point of zero charge, pH PZC. The adsorbed quantity of Pb2+ and the immersion enthalpy in solution of different pH values for CM activated carbon showed that the values are the highest for pH 4, 15.7 mgg-1 and 27.6 Jg-1 respectively. Pb2+ adsorption isotherms and immersion enthalpy were determined for modified activated carbons and the highest values were obtained for the activated carbon that showed the highest content of total acid sites on the surface.

Harmonical oscillator and electro-mechanical analogy: an interdiscinary experiment to high precision mass variation measurements

In general, the traditional Physics courses needs examples of the aplications of the Physics concepts in other areas such as Chemistry and Biology. This lacks tend to demotivate Chemistry and Biology students regarding to deal with Physical concepts developed in classroom. In this work, the analogy among mechanic and electric oscillators is investigated to be applied in Chemistry and Biology areas, showing to be valuable due to its aplication in techniques that aims to measure mass variation with high precision. This measure could be made in a direct or indirect way. These techniques are known as electrogravimetric techniques and they are important in biosensor aplications. Thus, this paper explores the electromechanic analogy in an interdisciplinary way involving areas like Physics, Chemistry and Biology. Based on this analogy, it is proposed an experiment that can be applied in different ways, i.e. by an basic approach or more deeper, depending on the students specific formation, in other words, Physics, Chemistry or Biology.

VARIATION OF MICROFIBRIL ANGLE OF Pinus radiata D. Don IN RELATION TO TREE SPACING IN CHILEAN PLANTATIONS

ABSTRACTFour stands of 28-year-old radiata pine (Pinus radiata D. Don) grown in the eighth region (Biobio) of Chile were sampled to determine the effect of tree spacing on the microfibril angle. The samples were taken at two different stem levels of the tree, 2.5 m and 7.5 m, with increment strip taken in the Nothern direction. The four experimental stands were characterized by the following spacing 2x2, 2x3, 3x4 and 4x4. The microfibril angle was measured by X-ray diffraction with the SilviScan technology at the FP-Innovation-Paprican Division in Vancouver, Canada. The results showed a significant effect of tree spacing on the microfibril angle in both juvenile wood and mature wood as well as at the two stem levels considered. The minimum (9.42º) was reached in 2x2 stand at 7.5 m in mature wood, while maximum microfibril angle (24.54º) was obtained in 2x3 stand at 2.5 m in juvenile wood. Regarding the effect of tree spacing, 4x4 stand had the lowest microfibril angle,except in mature wood at 7.5 m where 4x4 had the highest microfibril angle (11°) of the four stands.

Determination of the influence of the variation of reducing and non-reducing sugars on coffee quality with use of artificial neural network

The present study aimed at evaluating the use of Artificial Neural Network to correlate the values resulting from chemical analyses of samples of coffee with the values of their sensory analyses. The coffee samples used were from the Coffea arabica L., cultivars Acaiá do Cerrado, Topázio, Acaiá 474-19 and Bourbon, collected in the southern region of the state of Minas Gerais. The chemical analyses were carried out for reducing and non-reducing sugars. The quality of the beverage was evaluated by sensory analysis. The Artificial Neural Network method used values from chemical analyses as input variables and values from sensory analysis as output values. The multiple linear regression of sensory analysis values, according to the values from chemical analyses, presented a determination coefficient of 0.3106, while the Artificial Neural Network achieved a level of 80.00% of success in the classification of values from the sensory analysis.

Floristic and structural variation of weeds in eucalyptus plantations as influenced by relief and time of year

The objective of this work was to analyze the floristic variation and phytosociological structure of weeds as influenced by relief and time of year in eucalyptus plantations in Santana do Paraíso and Guanhães - MG. The total area sampled for each locality was approximately 10 ± 3 hectares, comprising three types of relief: lowland, slope, and upper area. In each type of relief, 10 plots of 1 m² were sampled, corresponding to 30 plots per locality, where they were randomly allocated in a zigzag. The taxonomic identification was performed in four assessments, corresponding to the months of November and March, comprising two ratings each season, always at the same points, and geo-referenced using the Global Positioning System (GPS). A total of 3,893 individuals, 18 families and 61 species, were identified in Santana do Paraiso and a total of 1,166 individuals, 13 families and 58 species, in Guanhães. In both localities, the most representative families in terms of wealth were: Poaceae, Asteraceae, and Fabaceae. Galinsoga parviflora was the most abundant species. The Vernonia polyantes was identified only in the lowlands, while Arrabida florida was identified in the slope and upper area. On the other hand, Emilia coccinea, Sida rhombifolia, S. paniculatum and Spermacoce latifolia were common to all three environments. Commelina benghalensis was present only in the month of March, while G. parviflora was present only in the month of November. It was concluded that the floristic and phytosociological variation of weeds in eucalyptus plantations is influenced by the type of relief and time of year, which should guide the management practices used in the culture.

Fructan variation in the rhizophores of Vernonia herbacea (Vell.) Rusby, as influenced by temperature

The influence of climatic variations on fructan content in tropical regions is not well known. The present study deals with the effects of temperature on fructan contents in rhizophores of plants of Vernonia herbacea, a native species from the Brazilian cerrado vegetation. Intact plants and fragmented rhizophores were subjected to different temperatures under natural and controlled environmental conditions. Rhizophores of plants in pre-dormant stage (aerial parts showing some yellowish leaves) presented higher fructan content at 5oC than those kept at 25oC, whereas in dormant plants (aerial parts absent) temperature treatments did not affect fructan contents. Fragmented rhizophores obtained from dormant plants presented higher levels of fructo-polysaccharides at the end of the experiment than at the beginning of the treatment, regardless of the temperature they were stored, whereas fragments obtained from vegetative plants showed a decrease in fructan content under the same treatments. It was concluded that variations observed in fructan contents are related to the phenological state of the plants prior to the treatment rather than to extraneous temperatures they are subjected to during this stage.