Growth promotion of pineapple 'vitória' by humic acids and burkholderia spp. during acclimatization

In vitro propagation of pineapple produces uniform and disease-free plantlets, but requires a long period of acclimatization before transplanting to the field. Quicker adaptation to the ex vitro environment and growth acceleration of pineapple plantlets are prerequisites for the production of a greater amount of vigorous, well-rooted planting material. The combination of humic acids and endophytic bacteria could be a useful technological approach to reduce the critical period of acclimatization. The aim of this study was to evaluate the initial performance of tissue-cultured pineapple variety Vitória in response to application of humic acids isolated from vermicompost and plant growth-promoting bacteria (Burkholderia spp.) during greenhouse acclimatization. The basal leaf axils were treated with humic acids while roots were immersed in bacterial medium. Humic acids and bacteria application improved shoot growth (14 and 102 %, respectively), compared with the control; the effect of the combined treatment was most pronounced (147 %). Likewise, humic acids increased root growth by 50 %, bacteria by 81 % and the combined treatment by 105 %. Inoculation was found to significantly increase the accumulation of N (115 %), P (112 %) and K (69 %) in pineapple leaves. Pineapple growth was influenced by inoculation with Burkholderia spp., and further improved in combination with humic acids, resulting in higher shoot and root biomass as well as nutrient contents (N 132 %, P 131 %, K 80 %) than in uninoculated plantlets. The stability and increased consistency of the host plant response to bacterization in the presence of humic substances indicate a promising biotechnological tool to improve growth and adaptation of pineapple plantlets to the ex vitro environment.

Fertilization with filter cake and micronutrients in plant cane

The response of sugarcane to application of micronutrients is still not very well known. In view of the need for this information, the aim of this study was to evaluate the application of the micronutrients Zn, Cu, Mn, Fe, B, and Mo to plant cane in three soils, with and without application of filter cake. This study consisted of three experiments performed in the State of São Paulo, Brazil, (in Igaraçu do Tiete, on an Oxisol; in Santa Maria da Serra, on an Entisol, both in the 2008/2009 growing season; and in Mirassol, on an Ultisol, in the 2009/2010 growing season) in a randomized block design with four replications with a 8 x 2 factorial combination of micronutrients (1 - no application/control, 2 - addition of Zn, 3 - addition of Cu, 4 - addition of Mn 5 - addition of Fe, 6 - addition of B, 7 - addition of Mo, 8 - Addition of Zn, Cu, Mn, Fe, B, and Mo) and filter cake (0 and 30 t ha-1 of filter cake) in the furrow at planting. The application of filter cake was more efficient than of Borax in raising leaf B concentration to sufficiency levels for sugarcane in the Entisol, and it increased mean stalk yield in the Oxisol. In areas without filter cake application, leaf concentrations were not affected by the application of Zn, Cu, Mn, Fe, B, and Mo in the furrow at planting; however, Zn and B induced an increase in stalk and sugar yield in micronutrient-poor sandy soil.

Competitive sorption and desorption of phosphate and citrate in clayey and sandy loam soils

The increase of organic acids in soils can reduce phosphorus sorption. The objective of the study was to evaluate the competitive sorption of P and citrate in clayey and sandy loam soils, using a stirred-flow system. Three experiments were performed with soil samples (0-20 cm layer) of clayey (RYL-cl) and sandy loam (RYL-sl) Red Yellow Latosols (Oxisols). In the first study, the treatments were arranged in a 2 × 5 factorial design, with two soil types and five combinations of phosphorus and citrate application (only P; P + citrate; and citrate applied 7, 22, 52 min before P); in the second, the treatments were arranged in a 2 × 2 factorial design, corresponding to two soils and two forms of P and citrate application (only citrate and citrate + P); and in the third study, the treatments in a 2 × 2 × 6 factorial design consisted of two soils, two extractors (citrate and water) and six incubation times. In the RYL-cl and RYL-sl, P sorption was highest (44 and 25 % of P application, respectively), in the absence of citrate application. Under citrate application, P sorption was reduced in all treatments. The combined application of citrate and P reduced P sorption to 25.8 % of the initially applied P in RYL-cl and to 16.7 % in RYL-sl, in comparison to P without citrate. Citrate sorption in RYL-cl and RYL-sl was highest in the absence of P application, corresponding to 32.0 and 30.2 % of the citrate applied, respectively. With P application, citrate sorption was reduced to 26.4 and 19.7 % of the initially applied citrate in RYL-cl and RYL-sl, respectively. Phosphorus desorption was greater when citrate was used. Phosphorus desorption with citrate and water was higher in the beginning (until 24 h of incubation of P) in RYL-cl and RYL-sl, indicating a rapid initial phase, followed by a slow release phase. This suggests that according to the contact time of P with the soil colloids, the previously adsorbed P can be released to the soil solution in the presence of competing ligands such as citrate. In conclusion, a soil management with continuous input of organic acids is desirable, in view of their potential to compete for P sorption sites, especially in rather weathered soils.

Soil water erosion under different cultivation systems and different fertilization rates and forms over 10 years

The action of rain and surface runoff together are the active agents of water erosion, and further influences are the soil type, terrain, soil cover, soil management, and conservation practices. Soil water erosion is low in the no-tillage management system, being influenced by the amount and form of lime and fertilizer application to the soil, among other factors. The aim was to evaluate the effect of the form of liming, the quantity and management of fertilizer application on the soil and water losses by erosion under natural rainfall. The study was carried out between 2003 and 2013 on a Humic Dystrupept soil, with the following treatments: T1 - cultivation with liming and corrective fertilizer incorporated into the soil in the first year, and with 100 % annual maintenance fertilization of P and K; T2 - surface liming and corrective fertilization distributed over five years, and with 75 % annual maintenance fertilization of P and K; T3 - surface liming and corrective fertilization distributed over three years, and with 50 % annual maintenance fertilization of P and K; T4 - surface liming and corrective fertilization distributed over two years, and with 25 % annual maintenance fertilization of P and K; T5 - fallow soil, without liming or fertilization. In the rotation the crops black oat (Avena strigosa ), soybean (Glycine max ), common vetch (Vicia sativa ), maize (Zea mays ), fodder radish (Raphanus sativus ), and black beans (Phaseolus vulgaris ). The split application of lime and mineral fertilizer to the soil surface in a no-tillage system over three and five years, results in better control of soil losses than when split in two years. The increase in the amount of fertilizer applied to the soil surface under no-tillage cultivation increases phytomass production and reduces soil loss by water erosion. Water losses in treatments under no-tillage cultivation were low in all crop cycles, with a similar behavior as soil losses.

Transfer of cadmium and barium from soil to crops grown in tropical soils

Phytotoxicity and transfer of potentially toxic elements, such as cadmium (Cd) or barium (Ba), depend on the availability of these elements in soils and on the plant species exposed to them. With this study, we aimed to evaluate the effect of Cd and Ba application rates on yields of pea (Pisum sativum L.), sorghum (Sorghum bicolor L.), soybean (Glycine max L.), and maize (Zea mays L.) grown under greenhouse conditions in an Oxisol and an Entisol with contrasting physical and chemical properties, and to correlate the amount taken up by plants with extractants commonly used in routine soil analysis, along with transfer coefficients (Bioconcentration Factor and Transfer Factor) in different parts of the plants. Plants were harvested at flowering stage and measured for yield and Cd or Ba concentrations in leaves, stems, and roots. The amount of Cd accumulated in the plants was satisfactorily evaluated by both DTPA and Mehlich-3 (M-3). Mehlich-3 did not relate to Ba accumulated in plants, suggesting it should not be used to predict Ba availability. The transfer coefficients were specific to soils and plants and are therefore not recommended for direct use in risk assessment models without taking soil properties and group of plants into account.

LAYERED DOUBLE HYDROXIDES: NANOMATERIALS FOR APPLICATIONS IN AGRICULTURE

The current research aims to introduce Layered Double Hydroxides (LDH) as nanomaterials to be used in agriculture, with particular reference to its use as storage and slow release matrix of nutrients and agrochemicals for plant growing. Structural characteristics, main properties, synthesis methods and characterization of LDH were covered in this study. Moreover, some literature data have been reported to demonstrate their potential for storage and slow release of nitrate, phosphate, agrochemicals, besides as being used as adsorbent for the wastewater treatment. This research aims to expand, in near future, the investigation field on these materials, with application in agriculture, increasing the interface between chemistry and agronomy.

Nitrogen and Potassium in Narrow-Row Cotton

ABSTRACT Information on fertilizer management for cotton in narrow-row cropping system is scarce; therefore, studies are needed to improve nutrient stewardship for such systems. The aim of this study was to evaluate the effects of nitrogen and potassium application on yield and fiber quality of cotton under a narrow-row system. A field trial was carried out for three years, where the treatments were set up in an incomplete factorial arrangement [(4 × 4) + 1] under a randomized block design, with four N rates (20, 40, 60, and 80 kg ha-1), four K2O rates (0, 40, 80, and 120 kg ha-1), and one control (no N or K2O), for a total of 17 treatments, with four replicates. Urea and potassium chloride were applied on the soil surface 20 days after crop emergence. Varieties used were FMT 701 (2009/2010 and 2010/2011) and FMT 709 (2011/2012). Cotton yield and fiber quality parameters were measured. In the narrow-row cropping system, cotton lint yield was positively affected by N and K application. Cotton yield in relation to K applications was not dependent on N rates. Potassium application increased the micronaire index and fiber resistance, whereas high N rates reduced fiber resistance.

Matriconditioning integrated with gibberellic acid to hasten seed germination and improve stand establishment of pepper and tomato

Emergence and stand establishment of tomato (Lycopersicon lycopersicum (L.) (Karsten ex Farw) and pepper (Capsicum annus L.) seeds are often slow and erratic, particularly under stress conditions. Field emergence trials sometimes have not responded to priming in pepper. This study examined the combined effects of matriconditioning and gibberellin application on the germination and stand establishment of pepper and tomato seeds. Pepper and tomato seeds were conditioned with a solid carrier, Micro Cel E, in the presence of gibberellic acid (GA) for 1, 2 , 3 and 4 days at 15 and 25ºC. The results showed that, in all cases, even under stress conditions, the combination of matriconditioning with GA was effective in improving germination and emergence of pepper and tomato. The germination time was, in average, reduced by 2 to 3 days by primed seeds. Thus, matriconditioning, during which germination is suspended, provides an unique means to rapidly and efficiently digest the endosperm by GA-induced enzymes and reduce the mechanical restraints of endosperm thus providing energy to start and sustain embryo growth.

Growth components and zinc recovery efficiency of upland rice genotypes

The objective of this work was to evaluate Zn use efficiency by upland rice genotypes. The experiment was carried out in a greenhouse, with ten upland rice genotypes grown on an Oxisol (Typic Hapludox) with no application, and with application of 10 mg kg-1 Zn, applied as zinc sulfate. Shoot dry weight, grain yield, Zn harvest index, Zn concentration in shoot and in grain were significantly influenced by soil Zn levels and genotypes. However, panicle number and grain harvest index were significantly affected only by genotype. Genotypes CNA8557, CNA8540 and IR42 produced higher grain yield than other genotypes. Genotypes showed significant variability in Zn recovery efficiency. On average, 13% of the applied Zn was recovered by upland rice genotypes. Genotypes with high Zn recovery efficiency could be used in breeding of Zn efficient upland rice cultivars. Higher level of soil Zn (10 mg kg-1) increased significantly the concentrations of plant Cu and Mn. However, Fe concentrations in plant (shoot and grain) were not influenced by soil Zn levels.

Seed priming and sulfur effects on soybean cell membrane stability and yield in saline soil

The objective of this work was to determine the effects of seed priming and sulfur application on cell membrane characteristics, seedling emergence, chlorophyll content and grain yield of soybean (Glycine max) in saline soil. A complete-block design in 4x3 factorial arrangement with three replicates was used to test four types of seed priming (water, auxin, gibberellin and non-priming) and three levels of sulfate availability (0, 70 and 140 kg ha-1 K2SO4). The soil had a silty loam texture with an electrical conductivity of 3.61 ds m-1, a pH of 8.2 and a saturation percentage of about 46%. Seed priming had significant effects on mean emergence rate (MER), emergence percentage, relative water content (RWC) of leaves, relative chlorophyll content, time of maturity, shoot length and grain yield. The highest values for these variables were observed in the priming treatments, except for the time of maturity. Sulfur application had significant effects on MER, shoot length, RWC, membrane injury index and grain yield. Priming treatments provide greater emergence rates and grain yields and interact sinergicaly with sulfur rates.

APPLICATION OF OZONE AIMING TO KEEP THE QUALITY OF STRAWBERRIES USING A LOW COST REACTOR

RESUMO O morango é uma fruta de alto valor comercial e tem uma rápida deterioração, como a demanda por produtos saudáveis, seguros sob o ponto de vista microbiológico e livre de produtos químicos aumenta cada vez mais, o método de aplicação do gás ozônio em uma atmosfera controlada foi proposto. O objetivo deste trabalho foi verificar a eficiência do gás ozônio produzido por um reator, a fim de que os pequenos produtores de morangos possam usá-lo, contribuindo, assim, para as economias regionais. Morangos (Fragaria ananassa) variedade Oso Grande, colhidasna região de Minas Gerais foram divididas dois grupos: o primeiro recebeu tratamento com ozônio e o segundo não. No primeiro grupo, o ozônio foi aplicado durante 20 minutos a partir de um reator de Corona. Os frutos foram armazenados a 4 ° C, por períodos de 5, 10 e 15 dias. A qualidade dos frutos foi relata a partir dos níveis de sólidos solúveis totais (SS), acidez titulável (AT ), pH, compostos fenólicos (CF), ácido ascórbico (AA), perda de massa fresca (PM%) e análise microbiológica (AM), em diferentes tempos de armazenamento de frutos ozonizados e não ozonizados. O uso de gás ozônio foi eficiente para a pós-colheita de morango. Os níveis de microrganismos estão dentro dos limites aceitáveis e as propriedades físicas e químicas foram mantidas.

Estado da arte da cromatografia gasosa de alta resolução e alta temperatura

The developments in stationary phase synthesis and capillary column technology, have opened new perspectives in analysis of high molecular mass compounds (³600 daltons) and thermolabile organic compounds by High Temperature High Resolution Gas Chromatography (HT-HRGC). HT-HRGC is a new analytical borderline and its application to the analysis of high molecular mass compounds is still in its infancy. The apolar and medium polar gum phases can now be operated at temperatures up to 400-480ºC, being used for the analysis of n-alcanes up to C-100, lipids, oligosaccharides, industrial resins, polyglycerols, cyclodextrins, porphyrins, etc. This technique should play a leading role as a powerful tool, for many different analysis types, in multidisciplinary fields of Science.

Catalyzed and non-catalyzed synthesis of bioactive monastrol

The bioactive 3,4-dihydropyrimidin-2(1H)-thione derivative known as Monastrol was synthesized under catalyzed and non-catalyzed conditions through the Biginelli multicomponent reaction under solvent-free conditions. The use of two Lewis acids (FeCl3 and CuCl2) and two Brønsted acids (HCl and CF3COOH) as catalysts improved the reaction yields of the transformation compared with the non-catalyzed reaction. The experiments investigated catalysis and its role, the importance of multicomponent reactions and their green features, and the application of these concepts to the synthesis of a biologically important structure.

INTERACTIONS: DESIGN, IMPLEMENTATION AND EVALUATION OF A COMPUTATIONAL TOOL FOR TEACHING INTERMOLECULAR FORCES IN HIGHER EDUCATION

Intermolecular forces are a useful concept that can explain the attraction between particulate matter as well as numerous phenomena in our lives such as viscosity, solubility, drug interactions, and dyeing of fibers. However, studies show that students have difficulty understanding this important concept, which has led us to develop a free educational software in English and Portuguese. The software can be used interactively by teachers and students, thus facilitating better understanding. Professors and students, both graduate and undergraduate, were questioned about the software quality and its intuitiveness of use, facility of navigation, and pedagogical application using a Likert scale. The results led to the conclusion that the developed computer application can be characterized as an auxiliary tool to assist teachers in their lectures and students in their learning process of intermolecular forces.

Biomass allocation and water use efficiency in fertigated sweet pepper

The use of productivity information and efficiency of water use is important for the economic analysis of production and irrigation management, and also helps the economy of water use, which is essential to plant life. The objective of this study was to evaluate the biomass allocation, the water use efficiency and water content in fruits of sweet pepper cropped under the influence of irrigation blades and potassium doses. The statistic design was a completely randomized factorial scheme (5 x 2) and four replications, with five irrigation blades (80; 90; 100; 110 and 120% of crop evapotranspiration) and two levels of potassium (80 and 120 kg K2O ha-1 ), applied according to phenological phase, through a system of drip irrigation with self-compensated drippers, installed in a battery of 40 drainage lysimeters cultivated with sweet pepper (Maximos F1), at Federal Rural University of Pernambuco (UFRPE), Recife, state of Pernambuco, Brazil. The dry biomass production of sweet pepper was influenced by fertigation regimes; when it was set the lowest dose, estimates of the efficiency of water use and moisture in the fruit occurred with the use of irrigation depth of 97 and 95% of ETc, respectively.