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Rio de Janeiro, Brazil

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 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.,Sao Paulo State University | De Oliveira M.L.,Sao 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.

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.

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.

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