Photosynthetic characteristics of hybrid and conventional rice plants as a function of plant competition

The objective of this work was to evaluate the characteristics related to the photosynthetic ability of hybrid and inbred rice varieties, as a way to assess which of the two presented higher potential to stand out under conditions of competition. The trial was set in a greenhouse in completely randomized block design and 2 x 6 factorial scheme with four replications. Factor A consisted of rice varieties (hybrid or inbred) and factor B by competition levels. Treatments consisted in maintaining one plant of either BRS Pelota (inbred) or Inov (hybrid) variety at the center of the plot, under competition with 0, 1, 2, 3, 4 or 5 plants of the variety BRS Pelota at the periphery of the experimental unit, according to the treatment. Fifty days after emergence (DAE), sub-stomatal CO2 concentration (Ci - mmol mol-1), photosynthetic rate (A - mmol m-2 s-1) and CO2 consumed (DC - mmol mol-1) were quantified, as well as shoot dry mass(SDM).Hybrid plants present higher photosynthesis capacity than inbred plants, when competing with up to 3 times its own density. When under the same competitive intensity, hybrid plants surpass the inbred. However, it should be emphasized that, when in farm condition, the lower competitive capacity with weeds often attributed to the hybrid varieties, probably is due to their lower planting density, but if weed competition is kept at low levels, hybrid rice plants may perform in the same way or usually better than inbred plants.

Sugarcane tolerance to ratoon eradication with glyphosate determined by physiological responses

This study aimed to evaluate the tolerance of sugarcane cultivars to ratoon eradication under different glyphosate rates by means of physiological responses. Therefore, a trial was carried out in randomized complete blocks with 4 x 4 factorial design (cultivars x rates) totaling 16 treatments with four replicates. The cultivars IAC91-5155, IACSP93-3046, and IAC86-2480 and IAC87-3396 and the glyphosate rates 0 g ha-1; 1,920 g ha-1; 2,400 g ha-1; 2,880 g ha-1 were tested. The variables analyzed were percentage of tiller mortality, quantum efficiency of PSII (Fv/Fm) and SPAD index. The results showed that there are differences among sugarcane cultivars for tiller eradication and for physiological responses with glyphosate different rates. The rate of 2,880 g ha-1 was the most efficient in eliminating sugarcane tillers. The cultivars IAC86-2480, IAC87-3396 and IACSP93-3046 were the most sensitive and the IAC91-5155 tolerated, for a longer period of time, the damage to the photosynthetic apparatus of the ratoons caused by glyphosate desiccation. Due to different responses, different managements should be considered for eliminating ratoons of different cultivars.

Cryptoglena, Monomorphina and Phacus (Euglenophyceae) of a reservoir in the State of Rio Grande do Sul, southern Brazil

Taxonomic survey of representatives of genera Cryptoglena Ehrenberg emend. Kosmala & Zakry´s, Monomorphina Mereschkowsky emend. Kosmala & Zakry´s and Phacus Dujardin (Euglenaceae, Euglenophyceae) of a reservoir in the municipality of Triunfo (30°02'15" S, 51°13'13" W), state of Rio Grande do Sul, southern Brazil. Samplings were performed at two stations during 14 consecutive months, from February 1995 to March 1996. Sixteen taxa including nine species, three varieties that are not typical of their respective species and one taxonomic forma also not typical of Phacus, two species of Monomorphina and one of Cryptoglena were identified. Phacuspseudobicarinatus is described as a new species. Phacuslongicauda (Ehrenberg) Dujardin var. longicauda, P. longicauda (Ehrenberg) Dujardin var. tortus Lemmermann, P. orbicularis Hübner, P. pleuronectes (O.F. Müller) Dujardin and P. pseudobicarinatusnov. sp. were the best represented taxa geographycally, occurring in more than 55% of samples studied. Phacuslongicauda var. longicauda and P. longicauda var. tortus were characteristic by their wide tolerance to the following environmental variables: pH, water temperature, organic matter concentration, total phosphorus and the nitrogen series (nitrite, nitrate, ammonium and total nitrogen). Phacusundulatus f. major is cited for the first time for Brazil.

Pigmented Euglenophytes in a natural and shallow lake in the semiarid region of Paraíba State, Brazil

A floristic survey of the class Euglenophyceae in Panati Lake (7º11'14" S and 36º49'52" W) is presented. The samples were collected between November 2005 and April 2007 along the margins of the lake, and a total of 29 taxa were collected, described, and illustrated, comprising 11 specifics and 18 infraspecifics, with five typical and 13 non-typical varieties. The genus Trachelomonas showed the greatest richness (13 taxa), followed by the genus Lepocinclis (seven taxa). All of the 29 taxa cataloged had been previously reported for Brazil, most with wide geographical distributions, but all were new records for Paraíba State, and 25 new for northeastern Brazil - reflecting the need for more taxonomic studies of the Euglenophyceae in these locations.

Use of canonical variates in genetic divergence studies

Exact correlation coefficients between a canonical variate and measured traits were derived to evaluate genetic divergence among varieties. This method allows the plant breeder to determine which traits contribute significantly to genetic divergence and, also, to identify the most important among them. An example is presented, related to a trial where 28 varieties of maize were evaluated for two traits

Predicting variety composite means without diallel crossing

Prediction of variety composite means was shown to be feasible without diallel crossing the parental varieties. Thus, the predicted mean for a quantitative trait of a composite is given by: Yk = a1 sigmaVj + a2sigmaTj + a3 - a4, with coefficients a1 = (n - 2k)/k²(n - 2); a2 = 2n(k - 1)/k²(n - 2); a3 = n(k - 1)/k(n - 1)(n - 2); and a4 = n²(k - 1)/k(n - 1)(n - 2); summation is for j = 1 to k, where k is the size of the composite (number of parental varieties of a particular composite) and n is the total number of parent varieties. Vj is the mean of varieties and Tj is the mean of topcrosses (pool of varieties as tester), and and are the respective average values in the whole set. Yield data from a 7 x 7 variety diallel cross were used for the variety means and for the "simulated" topcross means to illustrate the proposed procedure. The proposed prediction procedure was as effective as the prediction based on Yk = - ( -)/k, where and refer to the mean of hybrids (F1) and parental varieties, respectively, in a variety diallel cross. It was also shown in the analysis of variance that the total sum of squares due to treatments (varieties and topcrosses) can be orthogonally partitioned following the reduced model Yjj’ = mu + ½(v j + v j’) + + h j+ h j’, thus making possible an F test for varieties, average heterosis and variety heterosis. Least square estimates of these effects are also given

Studies on ATP-diphosphohydrolase nucleotide-binding sites by intrinsic fluorescence

Potato apyrase, a soluble ATP-diphosphohydrolase, was purified to homogeneity from several clonal varieties of Solanum tuberosum. Depending on the source of the enzyme, differences in kinetic and physicochemical properties have been described, which cannot be explained by the amino acid residues present in the active site. In order to understand the different kinetic behavior of the Pimpernel (ATPase/ADPase = 10) and Desirée (ATPase/ADPase = 1) isoenzymes, the nucleotide-binding site of these apyrases was explored using the intrinsic fluorescence of tryptophan. The intrinsic fluorescence of the two apyrases was slightly different. The maximum emission wavelengths of the Desirée and Pimpernel enzymes were 336 and 340 nm, respectively, suggesting small differences in the microenvironment of Trp residues. The Pimpernel enzyme emitted more fluorescence than the Desirée apyrase at the same concentration although both enzymes have the same number of Trp residues. The binding of the nonhydrolyzable substrate analogs decreased the fluorescence emission of both apyrases, indicating the presence of conformational changes in the neighborhood of Trp residues. Experiments with quenchers of different polarities, such as acrylamide, Cs+ and I- indicated the existence of differences in the nucleotide-binding site, as further shown by quenching experiments in the presence of nonhydrolyzable substrate analogs. Differences in the nucleotide-binding site may explain, at least in part, the kinetic differences of the Pimpernel and Desirée isoapyrases.

The husk fiber of Cocos nucifera L. (Palmae) is a source of anti-neoplastic activity

In the present study, we investigated the in vitro anti-tumoral activities of fractions from aqueous extracts of the husk fiber of the typical A and common varieties of Cocos nucifera (Palmae). Cytotoxicity against leukemia cells was determined by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. Cells (2 x 104/well) were incubated with 0, 5, 50 or 500 µg/mL high- or low-molecular weight fractions for 48 h, treated with MTT and absorbance was measured with an ELISA reader. The results showed that both varieties have almost similar antitumoral activity against the leukemia cell line K562 (60.1 ± 8.5 and 47.5 ± 11.9% for the typical A and common varieties, respectively). Separation of the crude extracts with Amicon membranes yielded fractions with molecular weights ranging in size from 1-3 kDa (fraction A) to 3-10 kDa (fraction B) and to more than 10 kDa (fraction C). Cells were treated with 500 µg/mL of these fractions and cytotoxicity was evaluated by MTT. Fractions ranging in molecular weight from 1-10 kDa had higher cytotoxicity. Interestingly, C. nucifera extracts were also active against Lucena 1, a multidrug-resistant leukemia cell line. Their cytotoxicity against this cell line was about 50% (51.9 ± 3.2 and 56.3 ± 2.9 for varieties typical A and common, respectively). Since the common C. nucifera variety is extensively cultured in Brazil and the husk fiber is its industrial by-product, the results obtained in the present study suggest that it might be a very inexpensive source of new antineoplastic and anti-multidrug resistant drugs that warrants further investigation.

Resveratrol inhibits the intracellular calcium increase and angiotensin/endothelin system activation induced by soluble uric acid in mesangial cells

Resveratrol (Resv) is natural polyphenol found in grapes. This study evaluated the protective effect of Resv against the effects of uric acid (UA) in immortalized human mesangial cells (ihMCs). ihMCs were preincubated with Resv (12.5 µM) for 1 h and treated with UA (10 mg/dL) for 6 or 12 h. The intracellular calcium concentration [Ca2+]i was quantified by fluorescence using flow cytometry. Angiotensinogen (AGT) and pre-pro endothelin-1 (ppET-1) mRNA were assayed by quantitative real-time RT-PCR. Angiotensin II (AII) and endothelin-1 (ET-1) were assayed by ELISA. UA significantly increased [Ca2+]i. Pre-incubation with Resv significantly reduced the change in [Ca2+]i induced by UA. Incubation with UA for 6 or 12 h also increased AGT mRNA expression and AII protein synthesis. Resv blunted these increases in AGT mRNA expression and AII protein. Incubation with UA in the ihMCs increased ppET-1 expression and ET-1 protein synthesis at 6 and 12 h. When ihMCs were pre-incubated with Resv, UA had a significantly diminished effect on ppET-1 mRNA expression and ET-1 protein synthesis at 6 and 12 h, respectively. Our results suggested that UA triggers reactions including AII and ET-1 production in mesangial cells. The renin-angiotensin system may contribute to the pathogenesis of renal function and chronic kidney disease. Resv can minimize the impact of UA on AII, ET-1 and the increase of [Ca2+]i in mesangial cells, suggesting that, at least in part, Resv can prevent the effects of soluble UA in mesangial cells.

Almond and peanut flours suppelmented with iron as potential ingredients to develop gluten-free cookies

Brazil is the second biggest worldwide producer of cookies and there are many varieties in the market; however, only a few are gluten-free. The objectives of this work were to formulate two gluten-free cookies added with iron, peanut or almond, and analyze their physicochemical, chromatic and sensory properties. Moisture, instrumental color (L*, a*, b* and C*), ash, proteins, lipids, iron, carbohydrates (estimated by difference), and water activity were determined. The acceptance of the products was assessed by 115 untrained taste panelists using a five-point hedonic scale. The data collected from the physicochemical analyses were submitted to Levene's, ANOVA, and Tukey's tests, which showed statistical difference (p < 0.05) in all the attributes for centesimal composition, water activity, and color of the cookies. Peanut and almond cookies could be considered sources of iron once they presented at least 15% of the daily recommended value of intake. They also garnered acceptance indexes of 80 and 85%, respectively, concluding that both formulations developed in this study were source of iron and contained high concentration of lipids and proteins with great sensory acceptance, suggesting their potential consumption by gluten-intolerants.

Discrimination of Brazilian red wines according to the viticultural region, varietal, and winery origin

This work evaluated the physicochemical composition of 171 red Brazilian wines from the 2006 vintage, which were represented by 21 varietals. These wines were produced by 58 Brazilian wineries in different regions of the country, with latitudes varying from 9º to 31º South. Physicochemical wine analysis was performed in the same year and discrimination in the viticultural regions, varietal wines, and wineries was performed by means of the principal component analysis (PCA). The main results show that wines from São Joaquim had higher values of A420, A520, A620, color intensity, total phenolic compounds, anthocyanins, and dry extracts, while those from Toledo had lower values of these variables; those from Vale do São Francisco had higher values of potassium, pH, density, and volatile acidity; from Serra do Nordeste A, they had higher titratable acidity; and from Planalto Superior B, higher hue. Regarding the varietal wines, PCA mainly discriminated the wines produced from the varieties Ancellotta, Teroldego, Egiodola, Refosco, Marselan, Cabernet Sauvignon, Pinotage, Pinot Noir, Malbec, Arinarnoa, Barbera, and Alfrocheiro. In relation to wineries, twenty two of them were discriminated by their higher values of some variables, i.e., three were characterized by color intensity; three by hue; eight by alcohol content; six by potassium, dry extract, density, and pH; and two by titratablel acidity.

Polyphenoloxidase and peroxidase in avocado pulp (Persea americana Mill.)

The aim of the present investigation was to evaluate the enzymatic activity of polyphenoloxidase and peroxidase in avocado pulps, from the Northwest area of Paraná-Brazil, in order to compare the varieties on their enzymatic activity for both, minimum and industrial processing. Enzymatic extracts were prepared from avocado pulp of Choquete, Fortuna and Quintal varieties, in green and ripe maturation stage. Thermal treatment was applied with temperatures 60, 65, 70, 75 and 80 °C. The enzymatic activities were determined by using spectrophotometer. A decline of polyphenoloxidase activity was observed in all of the varieties when both, temperature and time increased. Total inactivation of enzymes was not observed in the largest temperature. Fortuna and Choquete variety showed the lowest polyphenoloxidase activity in the ripe stage. Soluble peroxidase showed activity in the green stage, whereas, ionically bound peroxidase activity increased with the change from green to ripe maturation stage in Choquete variety.

Study of carbohydrates present in the cladodes of Opuntia ficus-indica (fodder palm), according to age and season

Types and content of carbohydrates were evaluated by chemical (spectrophotometric assay) and physicochemical (Thin Layer Chromatography - TLC and High Performance Liquid Chromatography - HPLC) methods in some Opuntia ficus-indica varieties according to age and season. The samples comprised four varieties of palm (giant, copena F1, clone 20, and round palm). The results demonstrated that the four varieties of palm contain a good quantity of neutral and acid sugars in both summer and winter seasons. However, samples collected in the summer presented a higher content of carbohydrates specially glucose, fructose, galactose, xylose, and arabinose. The tertiary cladode (old cladode) presented almost the double content of sugar found in the quaternary cladodes (young cladodes). Pectic polysaccharides were sequentially extracted with water at 60 ºC, and EDTA at 60 ºC solution resulting in Water-Soluble Pectin (WSP) and a Chelating-Soluble Pectin (CSP) respectively. Galacturonic acid was detected in the fractions WSP and CSP. However, the fraction CSP presented the highest content of sugar acid.

Colour, phenolic content and antioxidant activity of grape juice

Viticultural practices in the State of Santa Catarina, Brazil, have shown economic growth, with the production of grapes used to produce wines and grape juice. Grapes are rich in phenolic compounds which have drawn attention not only because of their important role in the development of products derived from grapes, but also for their potential beneficial health effects. The objective of this study was to evaluate commercial, organic and homemade grape juices produced in Santa Catarina. Grape juices were analyzed for total phenolic content, colour, and antioxidant activity. The commercial juices had the highest average values for total monomeric anthocyanins and total phenolics. There was a strong positive correlation (R = 0.9566) between the antioxidant activity and total phenolic content for the commercial juice. In addition, the Principle Components Analysis showed a strong positive correlation between the red colour and total monomeric anthocyanins. However, the total monomeric anthocyanis and polymeric anthocyanins showed a negative correlation.

Effect of soaking and cooking on phytate concentration, minerals, and texture of food-type soybeans

The increasing consumption of soybeans due to its bioactive compounds has attracted interest in describing the grain's constituents and variation during processing. Phytate has been the aim of much research since it chelates essential minerals but also has beneficial antioxidant effects. This study evaluated the variation of phytate, calcium, zinc, and iron during soaking and cooking of soybeans. The phytate: Zn and phytate: Fe molar ratios were determined in order to estimate the bioavailability of these minerals. Six food-type varieties were used: BR 36, BRS 213, BRS 216, BRS 232, BRS 155, and Embrapa 48. The samples were soaked in water 3:1 (w/w) for 12 hours at room temperature and cooked. Cooking time was determined by modeling the softening of each variety using fractional conversion. Water content, phytate, and minerals were determined in raw, soaked and cooked samples. The water content of raw grains for all varieties was 9.9 g.100 g-1 increasing to a range of 58.1-63.7 g.100 g-1 after soaking and 63.1-66.0 g.100 g-1 after cooking. Soaking caused a significant reduction in phytate (23-30%), but cooking caused no additional reduction. The phytate: Zn molar ratio was 20 indicating that zinc absorption could be impaired, while the phytate: Fe molar ratio was 8, below the level of compromising absorption