Search

Jambu (Acmella oleracea [(L.) RK Jansen]) is a vegetable of great importance in the Amazonian region; it can be found in the daily life of the citizens of the State of Pará (Brazil), since it is part of traditional dishes such as duck in tucupi and tacacá sauce. Although jambu is widely cultivated, agronomic information about its management remains scarce. The aim of the current study was to analyze the physiological potential of jambu seeds stored in different packages and environments. The investigated packages comprised glass, Eppendorf tubes, plastic bags and paper bags conditioned in refrigerator and under natural conditions in Castanhal, Pará, for 360 days. Seed germination, first germination count, emergence seedlings, germination and emergence speed index, and seedling dry weight and length were the variables evaluated at 40-day intervals. The experimental design was completely randomized, with four replicates of 50 seeds per treatment. Jambu seeds were only influenced by the environment where they were stored; the ones stored under natural conditions recorded decreasing behavior for the investigated variables until they reached zero, after 280 storage days. It was possible to conclude that the physiological potential of jambu seeds stored in refrigerator was better conserved. [ABSTRACT FROM AUTHOR]

Yellow pitahaya (Selenicereus megalanthus) has become an alternative for agricultural production in several municipalities of the province of Lengupá, in the department of Boyacá, Colombia, with an expanding and consolidating international market due to its status as an exotic fruit. This paper presents the results of a mixed methods research conducted with producers affiliated with the PITAFCOL organization in the municipality of Miraflores. The characteristics of the fruit and its market were described, and the socioeconomic conditions of the members of the association, as well as their attitudes of trust, reciprocity, and solidarity under the perspective of social capital (bonding type) were characterized. The conclusions point to the need to strengthen the trust within the organization for its consolidation, improve the organizational practices and seek new allies for processing the fruit to generate added value to the product, as well as alternative economic activities. [ABSTRACT FROM AUTHOR]

In production systems there is a close relationship between producers and nature. This situation has been studied within human ecology, so the objective of this paper was to describe the perception of cocoa producers in the municipalities of Caucasia and Necoclí (Antioquia, Colombia), about the link between human beings and nature. 74 diagnostic visits to producers were made and the information was analyzed using structural equations models, considering the latent variables: attitude, subjective norm, perception of control, intention, behavior, and satisfaction of lower and higher needs. The results indicated that the producers consider the care of nature important, that there is an influence of the natural environment to carry out this practice, and that to a lesser extent they are influenced by the family and the community. They also considered having the skills and knowledge but not the tools to do so, they stated that they intended to develop actions, but to a lesser extent they expressed that these actions were effectively implemented. They also found that most needs are easily met by living in natural environments. Two structural equations models were obtained: a) for the planned behavior, where it was found that the attitude influences the intention and this one in the behavior, and b) for the needs, where the satisfaction of lower needs facilitates the satisfaction of higher needs. In conclusion, caring for nature is important for participating producers and the natural environment facilitates the satisfaction of needs. [ABSTRACT FROM AUTHOR]

This paper presents a review on hydrogels applied to agriculture emphasizing on the use of natural fibers. The objectives were to examine, trends in research addressed to identify natural fibers used in hydrogels development and methods for modifying natural fibers, understand factors which determine the water retention capacity of a hydrogel. Consequently, this paper shows some methodologies used to evaluate the hydrogels efficiency and to collect in tables, relevant information in relation to methods of natural fibers modification and hydrogel synthesis. It was found that previous research focused on hydrogels development processed with biodegradable polymers such as starch, chitosan and modified natural fibers, cross-linked with potassium acrylate and acrylamide, respectively. In addition, current researches aimed to obtaining hydrogels with improved properties, which have allowed a resistance to climatic variations and soil physicochemical changes, such as pH, presence of salts, temperature and composition. In fact, natural fibers such as sugarcane, agave fiber and kapok fiber, modified with maleic anhydride, are an alternative to obtain hydrogels due to an increasing of mechanical properties and chemically active sites. However, the use of natural nanofibers in hydrogels, has been a successful proposal to improve hydrogels mechanical and swelling properties, since they give to material an elasticity and rigidity properties. A hydrogel efficiency applied to soil, is measured throughout properties as swellability, mechanical strength, and soil water retention. It was concluded that hydrogels, are an alternative to the current needs for the agricultural sector. [ABSTRACT FROM AUTHOR]

The sugar industry is an ideal sector for electricity cogeneration due to a large amount of burnable bagasse produce as a by-product. Bagasse produced in the sugar industry always consists of moisture affecting the efficiency of a boiler in the cogeneration plant. In our case study, a cogeneration plant run by bagasse burning found with bagasse moisture problem and suffocating with low power generation for the last few years. The boiler efficiency per tonne of bagasse is currently lower than optimal due to the substantial percentage of water present in the bagasse. A bagasse dryer design for this industry can improve the efficiency of a boiler as well as the cogeneration plant. In this paper, a pneumatic bagasse drying system is proposed to reduce the moisture content of bagasse from 48% to 30%. This work provides a full analysis of bagasse dryer design parameters, including specifications for dryer system components, such as feeders, fan, drying tube, and cyclone. The total bagasse drying system proposed is expected to be fitted within a 6 × 6 × 25 m space to dry 60 tph of bagasse, reducing the moisture content from 48% to 30%, in full compliance with all relevant Australian and company standards. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare two methods of estimating leaf area (leaf area meter LI-COR 3100 and ImageJ software) in oats. Renascem black oats and UTF Iguaçu white oats cultivars were evaluated. All the leaves of one plant per plot, with six repetitions, were evaluated every seven days to obtain five assessments for each cultivar. The leaves were identified and fixed on a white A4 sheet of paper with an indication of a known area (45 cm²), photographed and evaluated using a leaf area meter (LI-3100 - LI-COR). Leaf area was then estimated using ImageJ software. Estimates were obtained for standard deviation and coefficient of variation, and a simple linear regression equation was estimated based on the two estimation methods. Mean variances were tested using the 'F'-test and the means compared by the 't'-test. There was no difference between the leaf areas found by both methods. In addition, they were highly correlated, and variances were homogeneous. We concluded that ImageJ software can be used instead of the leaf area meter on the two oat cultivars evaluated. [ABSTRACT FROM AUTHOR]

In the majority of developing countries the research on the cellulolytic microorganisms has been scarcely oriented to the transformation of organic solid waste into compost, ignoring their enormous industrial potential. The main objective of the present investigation was to generate information on the capacity and diversity of the cellulolytic bacteria isolated from three different habitats. The study included soil samples from native forests and cereal producing farms as well as from compost piles. From each sample, a serial dilution until 10-4 was prepared and from each dilution test tubes containing liquid mineral medium and a strip of filter paper as a source of cellulose were inoculated. After three weeks of incubation, the population density of the cellulolytic microorganisms was estimated and from the filter paper strips streaks were made on nutrient agar medium and then on solid mineral medium, supplemented with cellulose. The bacterial growths were submitted to the Congo Red test and the ones with the greater potential were identified. In comparison to the soils the compost piles harbor a higher population density of cellulolytic microorganisms. In respect to the cellulolytic bacteria, in total were obtained 20 isolates, 19 from the native forests and 1 from a compost pile. Isolates 1, 2, 6, 7 and 14 showed a higher cellulolytic capacity with halos of hydrolysis between 0.65 and 0.30 cm. Isolate 1 was identified as Bacillus sp, isolate 7 as Pseudomonas sp, and isolate 6 as Erwinia sp. This information is useful to explore with confidence the potential of the cellulolytic bacteria in the industry. [ABSTRACT FROM AUTHOR]

In this paper we present the bases for the aseptic establishment of Monstera acuminata Koch and Monstera deliciosa Liebm from leaves and the induction of in vitro organogenesis of M. acuminata K. from discs of stems of young shoots. Different disinfection protocols were applied to mature leaves and young shoots, from which foliar explants of 1 cm2 of both species were extracted, and stem disks approximately 1 mm of thick in M. acuminata K. The explants were established in semi-solid media with different hormonal treatments during the stage of aseptic establishment and induction of organogenesis. Disinfection with 3% of sodium hypochlorite (NaClO) for 20 min and 50% Murashige y Skoog medium (1962) with PPM, led to less oxidation in the leaf explants of both species. All the explants in the two treatments belonging to M. deliciosa, grown in medium added with PPM and different disinfection protocols, survived, did not present contamination and more than 80% maintained answer's capacity until 49 days of culture. After 35 days of culture, with disinfection in Tween 20 + Ethanol 20% + 2.5% NaClO, and sowing of the explants in the MS medium added with 1 mg/l of BAP, 0.5 mg/l of AIA and 0.1 mg/l of ANA was induced to induce seven new shoots of stem disks. M. deliciosa had better ability to adapt to in vitro conditions. Advances in the establishment and induction of organogenesis in native araceas for wicker production are the basis for ex situ conservation of local populations. [ABSTRACT FROM AUTHOR]

The goals of this paper were to evaluate total polyphenol content (TPC), total flavonoid content (TFC), anti-oxidant capacity (AC) and reducing power (RP) of eight dark chocolates that are sold in Peru. Imported and domestic chocolate samples containing between 50% and 74% cacao were defatted. Defatted chocolate (DCh) was separated and treated to extract phenolic compounds. The TPC and AC were determined by using the Folin-Ciocalteu reagent and two in vitro models based on the free-radical capturing capacity DPPH and ABTS. The RP was evaluated by using the potassium pherricyanide method; in the TFCs assessments, catechin was used as the standard. Chocolate TPC varied between 1.69 ± 0.02 and 5.39 ± 0.17 mg gallic acid/g chocolate and AC (DPPH-IC50) varied between 52.97 ± 1.77 and 158.67 ± 2.04 µg/ml extract, and by means of ABTS the values were between 12.01 ± 0.18 and 32.74 ± 0.49 µmol TEAC/g chocolate. Chocolates with 71% and 72% cacao showed a greater antioxidant capacity, which was confirmed by the RP test. Chocolates showed different levels of TPC, TFC, AC and RP, depended on a large degree of the cacao percentage. However, in some cases there was no direct relationship among results, most likely due to different technological and thermal processes as well as different biological nature of cacao beans. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the chemical control of Asian soybean rust (Phakopsora pachyrhizi Syd. & P. Syd.) using different tips and spray nozzles under controlled conditions. Rooted trifolia placed inside an acrylic box containing macronutrients, micronutrients and vitamins were treated with epoxiconazol + pyraclostrobin, ciproconazol + azoxystrobin and tebuconazol fungicides. These fungicides were sprayed at a height of 0.5 m with two knapsack sprayers pressurized with CO2 gas (drop generator in four spray tips spaced by 0.5 m from each other) and another rotating nozzle (drop generator through a rotating nozzle). Untreated trifolia were controls. Water sensitive paper was placed next to each acrylic box to obtain median volume diameter (VMD), number of droplets.cm2 and coverage (%). Trifolia were inoculated 24 hours after that these were treated with fungicide, using a spore concentration adjusted to 2 x 104 uredospores.mL1. Then, the number of lesions and uredia.cm-2 in central leaflets were quantified. Lower number of lesions and uredia.cm2 were observed in leaflets treated with two fungicide mixtures using an AIRMIX 11001 tip. A lower VMD was found in leaflets sprayed with the fungicides azoxystrobin + epoxiconazol and tebuconazol, when compared to the leaflets treated with another mixture. The Asian rust control, as well as the number of droplets.cm2 and coverage, seems to be dependent on the interactions among fungicides and tips or nozzles. [ABSTRACT FROM AUTHOR]

For each vegetable species, there is a specific environment conditions to occur the seed germination process. However, there is a little information regarding the necessary conditions for Niger (Guizotia abyssinica (L.f.) Cass.) seeds germination. The aim of this research was to evaluate the influence of different temperatures and types of light on Niger (Guizotia abyssinica (L.f.) Cass.) seeds germination. Seeds were sown on two sheets of "germitest" paper inside plastic box type "gerbox" and placed on B.O.D. Treatments were constituted of two constant temperatures (15 °C and 25 °C, respectively) and an alternating temperature (20-30 °C) under 10 hours for the lowest temperature and 14 hours for the highest temperature and they were associated to the wavelengths as follows: blue (440 nm), green (560 nm), red (660 nm), extreme red (730 nm), white light and dark. The experiment was conducted in a completely randomized design with four replicates of 50 seeds. Effects of different temperatures and qualities of light were evaluated by seeds germination and vigor. Higher germination of Niger seeds is observed in temperatures of 25 and 20-30 °C and they can be considered as non-photoblastic. [ABSTRACT FROM AUTHOR]

This paper presents the conceptualization, methodological adjustment and experimental application of the micrometeorological technique eddy covariance - EC, to measure energy, water vapor and CO2 fluxes in two coffee agroecosystems: the first under full sunlight, and the second under shade, both with equatorial Andean hillslope conditions. With a footprint and fetch calculation, the required distance from the edge of the field in the prevailing wind direction to the EC tower is three times higher under shade than full sun. The shaded agroecosystem reached maximum average carbon fixation rates of 21.26 ± 2.469 μmolCO2.m-2s-1 (= 0.05) (61% higher than under 100% sunlight) which gives a high carbon sink capacity to the association of coffee plants with shading Pigeon peas (Cajanus cajan L). The average evapotranspiration rate was 2.33 ± 0.0102 mm.d-1 0.05) and 2.08 ± 0.00732 mm.d-1 under shade and 100% sunlight, respectively. The proportion of net radiation that reached the soil was 2% under shade and 4% under 100% sunlight. Likewise, the soil energy loss during the night was lower under shade, indicating less day-night temperature range in the latter agroecosystem. The methodological adjustment and the results of this first work using EC in Colombian coffee plantations, contribute to the development of reliable research regarding gas and energy exchanges between the atmosphere and ecosystems in conditions of the equatorial Andean hillslope. [ABSTRACT FROM AUTHOR]

Plant genetic improvement has a double scientific nature: it is both an empirical science of nature and an applied science of design. In this context, this paper provides an investigation of scientific prediction as an essential feature of plant genetic improvement as an applied science of design with special emphasis in the improvement of stone fruits (Prunus genus). In considering plant genetic improvement, we can speak of three levels of knowledge. These levels are associated with molecular biology (micro level); the genetic constitution of an individual (meso level); and the phenotype and overall appearance of the new release (macro level). These levels of reality affect both the type of prediction and the methodology applied. The prediction is the main objective of the plant genetic improvement as science of design. It is very important to have a knowledge of possible future to make a new design that will be complete within a few years, more than 12 years in the case of stone fruit that is the subject of this work. Finally, in developing a scientific prediction applied to Prunus breeding it is necessary to consider different internal (the genetic nature of the starting plant material, the available methodologies, etc.) and external (social acceptation, environmental factors, biotic and abiotic stresses, etc.) variables. The degree of knowledge of these variables determines the quality of the prediction in the design of the new Prunus varieties. [ABSTRACT FROM AUTHOR]

Several studies about juçara palm fruit (Euterpe edulis) have emphasized its high antioxidant capacity. However, there is a lack of studies comparing the effects of conservation technologies on the physicochemical and sensory quality of juçara pulp. This work aimed at evaluating the effects of gamma radiation (60Co) and pasteurization process on the physicochemical and sensory quality ofjuçara pulp. The irradiated (2.5 ± 0.06 kGy) and pasteurized (80°C/5 minutes) pulps were stored at 6°C, 90% RH, for 30 days (3 periods of analysis) and were analyzed for their microbiological, physicochemical (titratable acidity, soluble solids content, color, phenolic compounds, anthocyanin content, polyphenol oxidase and peroxidase activity) and sensory parameters (acceptance test). The physicochemical results were submitted to ANOVA for the 'F' test and the statistical difference of averages (P < 0.05) was determined by the Tukey's test. The results of the sensory analysis were submitted to Principal Component and Cluster Analysis. The gamma radiation did not show satisfactory results in the preservation ofjuçara pulp since there was a significant decrease in total phenolics and anthocyanin content. The pasteurized pulp maintained its physicochemical and sensory characteristics during storage. Therefore, we recommend the pasteurization as a good conservation technique to this kind of product, which presented a shelf-life of around 15 days. [ABSTRACT FROM AUTHOR]