ESALQ

Rio de Janeiro, Brazil
Rio de Janeiro, Brazil

Time filter

Source Type

The autoimmunization of the analysis of seedling growth by the use of computerized image can contribute to the evaluation of seed vigor. The aim of this research was to verify the effciency of computerized seedling image analysis by SVIS to detect differences of vigor between eggplant seed lots as compared to those provided by traditional vigor tests. Ten lots of eggplant seeds, cultivar Embu, were stored for 12 months in a room with controlled environment, at 20±1°C and 45-50% relative humidity. The water content of the seeds was monitored and physiological potential assessed at 0, 6 and 12 months after storage, with standard germination, accelerated aging (traditional and with saturated salt solution), electrical conductivity, seedling emergence on substrate and with the system of computerized image analysis (SVIS) of seedlings (seedling length, vigor and growth index). The experimental design was completely randomized with 4 replications and data were submitted to analysis of variance and means were compared by the Tukey test (p<0.05). The parameters obtained by the computerized seedling analysis with SVIS® software (seedling length and vigor and growth index) are efficient to differ between lots of high and low vigor eggplant seeds as traditional vigor methods.


Nunes M.A.,Centro APTA Citros Sylvio Moreira IAC | de Oliveira C.A.L.,São Paulo State University | De Oliveira M.L.,São Paulo State University | Kitajima E.W.,ESALQ | And 3 more authors.
Plant Disease | Year: 2012

The equivalent of US$75 million is spent each year in Brazil to control Brevipalpus phoenicis, a mite vector of Citrus leprosis virus C (CiLVC). In this study, we investigated the possibility that hedgerows and windbreaks normally found in citrus orchards could host CiLV-C. Mites confined by an adhesive barrier were reared on sweet orange fruit with leprosis symptoms then were transferred to leaves of Hibiscus rosa-sinensis, Malvaviscus arboreus, Grevilea robusta, Bixaorellana, and Citrus sinensis. Ninety days post infestation, the descendant mites were transferred to Pera sweet orange plants to verify the transmissibility of the virus back to citrus. Nonviruliferous mites which had no feeding access to diseased tissue were used as controls. Local chlorotic or necrotic spots and ringspots, symptoms of leprosies disease, appeared in most plants tested. Results generated by reversetranscription polymerase chain reaction with primers specific for CiLVC and by electron microscope analyses confirmed the susceptibility of these plants to CiLV-C. © 2012 The American Phytopathological Society.


Andreazza R.,Federal University of Rio Grande do Sul | Andreazza R.,Auburn University at Montgomery | Okeke B.C.,Auburn University at Montgomery | Pieniz S.,Federal University of Rio Grande do Sul | And 3 more authors.
Biological Trace Element Research | Year: 2012

Long-term copper application in vineyards and copper mining activities cause heavy metal pollution sites. Such sites need remediation to protect soil and water quality. Bioremediation of contaminated areas through bioleaching can help to remove copper ions from the contaminated soils. Thus, the aim of this work was to evaluate the effects of different treatments for copper bioleaching in two diverse copper-contaminated soils (a 40-year-old vineyard and a copper mining waste) and to evaluate the effect on microbial community by applying denaturing gradient gel electrophoresis (DGGE) of 16S ribosomal DNA amplicons and DNA sequence analysis. Several treatments with HCl, H2SO 4, and FeSO4 were evaluated by stimulation of bioleaching of copper in the soils. Treatments and extractions using FeSO4 and H2SO4 mixture at 30°C displayed more copper leaching than extractions with deionized water at room temperature. Treatment with H 2SO4 supported bioleaching of as much as 120 mg kg -1 of copper from vineyard soil after 115 days of incubation. DGGE analysis of the treatments revealed that some treatments caused greater diversity of microorganisms in the vineyard soil compared to the copper mining waste. Nucleotide Blast of PCR-amplified fragments of 16S rRNA gene bands from DGGE indicated the presence of Rhodobacter sp., Silicibacter sp., Bacillus sp., Paracoccus sp., Pediococcus sp., a Myxococcales, Clostridium sp., Thiomonas sp., a firmicute, Caulobacter vibrioides, Serratia sp., and an actinomycetales in vineyard soil. Contrarily, Sphingomonas was the predominant genus in copper mining waste in most treatments. Paracoccus sp. and Enterobacter sp. were also identified from DGGE bands of the copper mining waste. Paracoccus species is involved in the copper bioleaching by sulfur oxidation system, liberating the copper bounded in the soils and hence promoting copper bioremediation. Results indicate that stimulation of bioleaching with a combination of FeSO4 and H2SO4 promoted bioleaching in the soils and can be employed ex situ to remediate copper-impacted soils. © 2011 Springer Science+Business Media, LLC.


Andreazza R.,Federal University of Rio Grande do Sul | Andreazza R.,Auburn University at Montgomery | Okeke B.C.,Auburn University at Montgomery | Pieniz S.,Federal University of Rio Grande do Sul | And 3 more authors.
Biological Trace Element Research | Year: 2011

Environmental copper contamination is a serious human health problem. Copper reductase is produced by microorganisms to facilitate copper uptake by ATPases into the cells increasing copper biosorption. This study assessed the reduction of Cu(II) by cell-free extracts of a highly copper-resistant bacterium, Pseudomonas sp. strain NA, isolated from vineyard soil contaminated with copper. Both intact cells and cell-free extract of Pseudomonas sp. strain NA displayed substantial reduction of Cu(II). Intact cells reduced more then 80 mgL -1 of Cu(II) from medium amended with 200 mgL -1 of copper after 24 h of incubation. Cell-free extract of the isolate reduced more than 65% of the Cu(II) at initial copper concentration of 200 mgL -1 after 24 h. Soluble protein production was high at 72 h of incubation at 100 mgL -1 of copper, with more then 60 μgL -1 of total soluble protein in cell-free extract recorded. Cu(II) reduction by isolate NA was increased when copper concentration increased for both intact cells and cell-free extract. Results indicate that Pseudomonas sp. strain NA produces copper reductase enzyme as the key mechanism of copper biotransformation. © 2010 Springer Science+Business Media, LLC.


PubMed | Brawijaya University, ESALQ and Hasselt University
Type: Journal Article | Journal: Statistical methods in medical research | Year: 2015

This paper presents, extends, and studies a model for repeated, overdispersed time-to-event outcomes, subject to censoring. Building upon work by Molenberghs, Verbeke, and Demtrio (2007) and Molenberghs etal. (2010), gamma and normal random effects are included in a Weibull model, to account for overdispersion and between-subject effects, respectively. Unlike these authors, censoring is allowed for, and two estimation methods are presented. The partial marginalization approach to full maximum likelihood of Molenberghs etal. (2010) is contrasted with pseudo-likelihood estimation. A limited simulation study is conducted to examine the relative merits of these estimation methods. The modeling framework is employed to analyze data on recurrent asthma attacks in children on the one hand and on survival in cancer patients on the other.


da Silva L.O.,Federal Rural University of Pernambuco | da Silva A.P.N.,Bairro Universitario | Moura G.B.A.,Federal Rural University of Pernambuco | Lopes P.M.O.,Federal Rural University of Pernambuco | de Medeiros S.R.R.,ESALQ
Revista Caatinga | Year: 2011

The present work had as objective to carry through the agroclimatic zoning of the culture of surinam cherry in the state of Pernambuco. They had been used given average annual of minimum and maximum pluvial precipitation and pertaining temperatures of air the 201 climatologic station located in the main representative cities of the regions of the State for the elaboration of the water balance and the attainment of the thermal and water limits. The function density of probability of the distribution gamma was used to classify the dry, regular and rainy years. The maps of dry, regular and rainy years had been produced using interpolation for kriging. The results had presented 19 cities with full aptitude for dry years, 50 cities for regular years and 66 cities for rainy years apt to the culture of surinam cherry. The cities of Cortês, Gameleira and Palmares had revealed with better aptitudes agroclimatic for the culture of the surinam cherry in Pernambuco.


The plants are subject to the conditions of multiple stresses, such as water and salt stress, which limit their development and their chances of survival. Aware of the factors that control seed germination can generate support for management strategies of weed species. The objective of this study was to evaluate the possible effects of water stress caused by PEG and NaCl solutions on germination of wild Raphanus raphanistrum and Senna obtusifolia seeds. The seeding was done with four repetitions of 50 seeds on moistened paper with solutions of polyethylene glycol (PEG 6000) and NaCl at osmotic potentials of 0.0, -0.2, -0.4 and -0.8 MPa. The germination test was conducted at 25° C in the presence of light, evaluating the first test score to seven days after sowing, and weekly, germination (normal seedlings) until 35 days; it was also calculated the index germination rate. The results allowed the conclusion that water stress by PEG causes a greater reduction in force, speed of germination and accumulated germination of seeds of Raphanus raphanistrum and Senna obtusifolia seeds. The Senna obtusifolia was more tolerant to water stress.


The soil hydraulic conductivity K is a property that expresses the ability of the soil in conducting water. It is important for soil management, crops yield and the preservation of soil and environment. The soil hydraulic conductivity can be determined by means of laboratory and field methods, the first better experimentally controlled and the second with less degree of soil disturbing. Among the field methods, the instantaneous profile one is the most used, both the original and the modified in which a relation between the soil water content θ and the soil water redistribution time t is obtained assuming soil water total potential gradient equal to one. In order to analyse in more detail the method, a study was carried out with the objective of verifying the possibility to obtain the relation of θ as a function of t without the assumption of the existence of total potential gradient equal to one. The study was developed with data of four soils and the validation of the proposed relation was made by comparing the K(θ) function obtained from it and the K(θ) function obtained in the traditional way. From the results, it could be conclude that the proposed relation between θ and t for the instantaneous method showed to be valid and that the total potential gradient may affect both γ and K0 parameters of the K = K0 exp [γ(θ - θ0)] equation fitted to the experimental data. For the specific case of the soils evaluated in this work, the potential gradient had low influence on the γ parameter as compared with its influence on the K0 parameter, leading to the possibility of utilization of a mean potential gradient to obtain the K(θ) function. Besides, it was observed that the procedure to calculate the flux density from the curve of soil water storage as a function of redistribution time is much simpler than the original that has been used for this purpose in the instantaneous profile method.


Cato S.C.,ESALQ | Macedo W.R.,ESALQ | Peres L.E.P.,ESALQ | Castro P.R.C.,ESALQ
Horticultura Brasileira | Year: 2013

The aim of this study was to evaluate the effect of isolated and combined applications of gibberellic acid (gibberellin), indolbutyric acid (auxin) and kinetin (cytokinin) on vegetative and reproductive development of tomato test plants (Solanum lycopersicum cv. Micro- Tom), to better elucidate the interactions among these hormonal classes. The following treatments were accomplished through foliar application: GA3 (5 mg L-1); IBA (5 mg L-1); KIN (9 mg L-1); GA3 + IBA (5 mg L-1 + 5 mg L-1); GA3 + KIN (5 mg L-1 + 9 mg L-1); IBA + KIN (5 mg L-1 + 9 mg L-1); GA3 + IBA + KIN (5 mg L-1 + 5 mg L-1 + 9 mg L-1) and Stimulate® (100 mL L-1). Plants from the control were sprayed with water. Stimulate®, is a commercial liquid formulation containing KIN (90 mg L-1), GA3 (50 mg L-1) and IBA (50 mg L-1). We analyzed the shoot dry matter (g), root dry matter (g); fruit fresh matter (g); fruit dry matter (g) and fruit size (cm). The experimental design was completely randomized with nine treatments and fifteen replications. The treatment means were compared by Tukey's test. Some combined applications of GA3, IBA and KIN or Stimulate® promoted significant increases in the dry matter accumulation of roots and fresh and dry matter of fruit compared to the control. Besides the perspective to extend such results for commercial tomato production, the relevance of known hormonal interactions for the results obtained is discussed.


Bromeliads production in greenhouses is highly influenced by microclimate, which affects plants growth and development. Based on that, this study aimed to evaluate the influence of shading screens of different colors on microclimatic variables and Aechmea fasciata bromeliad growth in a greenhouse covered by transparent low-density polyethylene. The experiment had five treatments, with screens of different colors, inside a plastic greenhouse: thermo-reflective (T1); control without screen (T2); red (T3); blue (T4); and black (T5) screens, all of them with 70% of shading. From the 60 plants arranged in each one of the treatments 24 were evaluated, which were obtained randomly. The statistical design was completely randomized for the biometric variables. An automatic micrometeorological station was installed in each treatment, recording temperature, relative humidity and solar radiation. The plant parameters evaluated weekly were plant diameter and height, leaf width and length, and number of leaves per plant. The rosette diameter and leaf length were the parameters that presented the highest differences among treatments, which was basically a function of changes in solar radiation caused by the shading screens. The red screen provided the best conditions for A. fasciata bromeliad production.

Loading ESALQ collaborators
Loading ESALQ collaborators