Interferência de Euphorbia heterophylla no crescimento e acúmulo de macronutrientes da soja

O grau de interferência depende da densidade de plantas daninhas que infestam a soja. O objetivo deste trabalho foi avaliar características de crescimento e nutrição mineral da soja mantida em convivência com densidades crescentes de Euphorbia heterophylla. O experimento foi conduzido em Jaboticabal, SP, Brasil, entre outubro e dezembro de 2008, em vasos mantidos em campo aberto. Os tratamentos consistiram em submeter uma planta de soja por vaso à convivência com 0, 1, 2, 4, 8 e 16 plantas de E. heterophylla por vaso, da semeadura até o início do florescimento. Nesse período, avaliaram-se, apenas na soja, a altura e o número de trifólios, e em ambas as espécies, a matéria seca e o acúmulo de macronutrientes. Observou-se variação na altura de plantas e redução no número de trifólios e no acúmulo de matéria seca e macronutrientes da soja devido ao maior acúmulo de matéria seca e macronutrientes por densidades crescentes de E. heterophylla. Conclui-se que a soja mantida em convivência com E. heterophylla teve o crescimento e o acúmulo de macronutrientes reduzidos em razão da interferência imposta pela planta daninha.

Densidades de palha e condições de luminosidade na germinação de sementes de Euhphorbia heterophylla

It was studied the influence of sugarcane straw density and light conditions on the germination of seeds of Euphorbia heterophylla under controlled conditions. The experimental design was completely randomized design with four replications of 50 seeds, and the treatments were arranged in a 6 x 5 factorial, with six amount of sugarcane straw (0, 8, 10, 12, 14 and 16 t ha(-1)) and 5 types of light (constant light, constant darkness, alternating light and dark, short red and far red). The seeds were germinated in plastic type boxes covered by overlapping layers of straw and kept in germination. Assessments of germination were daily computing the normal seedlings, when they presented protusion roots visible and calculated the germination speed index (IGS). It was observed that the increase of different densities of straw and different wave lengths provided germination ranged from 83 to 97% and IGS between 9.85 to 15.36. The different densities of straw and wavelength did not suppress the germination of E. heterophylla. Therefore, the species was insensitive to light, so the presence of raw sugarcane system can't be considered a potential tool for controlling this species.

Deposição de glyphosate aplicado para controle de plantas daninhas em soja transgênica

Inúmeros fatores estão envolvidos na tecnologia de aplicação de um herbicida, sendo a deposição correta fundamental para que o produto possa expressar sua eficiência. Com o objetivo de avaliar a deposição de uma solução traçante constituída de glyphosate Roundup Ready (0,96 kg e.a. ha-1) + corante FDC-1 (1.500 ppm), foi conduzido um experimento em área semeada com soja transgênica e infestada com amendoim-bravo (Euphorbia heterophylla), localizada em Londrina-PR. As aplicações foram efetuadas em diferentes estádios de desenvolvimento da cultura, correspondendo a 17, 24, 31, 38 e 45 dias após a emergência da soja. Os alvos, plantas de soja, amendoim-bravo e placas na superfície do solo (linha e entrelinha), foram coletados após pulverização, e a solução traçante foi nestes depositada, posteriormente recuperada através de lavagem com agitação em água destilada. As amostras das soluções recuperadas foram submetidas à análise, utilizando-se procedimentos espectrofotométricos, e os resultados de absorbância convertidos para concentração em µL cm-2 e µL por planta. As freqüências acumuladas dos dados originais de depósito foram adequadamente ajustadas segundo modelo de Gompertz, apresentando elevada precisão (R² > 0,95). Os resultados indicaram que o depósito da calda de pulverização nas plantas de soja e amendoim-bravo reduziu progressivamente com o desenvolvimento da cultura e infestação, sugerindo que a maior garantia de eficiência de controle pode ser conseguida com aplicações precoces.

Déficit hídrico na eficiência de herbicidas e nas características bioquímicas de Euphorbia heterophylla

The objective of this work was to evaluate conditions the effectiveness of acetolactate synthase (ALS) and protoporphyrinogen oxidase (PROTOX) inhibitors in the Bidens pilosa control under two water deficit conditions, as well as to determine the action under the content of soluble carbohydrates and protein and free amino acids of weed. The experimental design was randomized completely design, with four replications, with the treatments setup in a factorial scheme 4x2, with four herbicides (fomesafen lactofen, chlorimuron-ethyl and imazethapyr), and two soil water conditions (-0.5 MPa and -0.01MPa). At 7, 14, 21 and 28 days after application (DAA), was assessed visually control efficiency of herbicides. For the determination of organic solutes plants were collected at 24, 48, 72 and 96 hours after application (HAA), except for the amino acids were analyzed 48, 72 e 96 HAA. Herbicides fomesafen and lactofen were efficient to control E. heterophylla, while the ALS inhibitors (chlorimuron-ethyl e imazethapyr) provided an unsatisfactory control. Water deficit altered the efficiency of herbicides, mainly chlorimuronethyl. Lactofen provided a smaller content of soluble carbohydrates, in the same way, the protein ranged in the 72 HAA, the lower value observed for imazethapyr e lactofen respectively. Herbicide lactofen increased the concentration of free amino acids, while the imposition of water deficit caused an increase in soluble carbohydrate content.

Estimativa da área foliar de Euphorbia heterophylla

Leaf area estimate may contribute to understand the relationships of interference among weeds and crops. The objective of this research was to obtain a mathematical equation to estimate the leaf area of Euphorbia heterophylla based on linear measures of the leaf blade. Correlation studies were carried out using the real leaf area and leaf length (C) and the maximum leaf width (L) of 200 leaf blades which were collected from several agroecosystems at Universidade Estadual Paulista in Jaboticabal, SP, Brazil. The evaluated statistic models were: linear Y = a + bx; simple linear Y = bx; geometric Y = ax b; and exponential Y = ab x. All of the evaluated models can be used for E. heterophylla leaf area estimation. The simple linear regression model is suggested using C*L and taking the linear coefficient equal to zero. Thus, an estimate of the leaf area of E. heterophylla can be obtained using the equation Af' = 0.6816*(C*L).

Herança genética e marcadores moleculares associados à resistência de Euphorbia heterophylla L. aos herbicidas inibidores da ALS e PROTOX

This study aimed to assess the genetic inheritance, determine the better DNA isolation protocol for this species and to identify molecular markers associated with the Wild Poinsettia (Euphorbia heterophylla L.) resistance ALS- and PROTOX- inhibiting herbicides and. The genetic inheritance of resistance was determined from crosses between E. heterophylla biotypes susceptible (S) and resistant (R), backcrosses and F2 generation. The complete dominance of resistance was confirmed with dose response curves. Ten adjusted methods for DNA isolation described in the literature were tested. The specific primers for ALS and PROTOX genes were designed from the consensus DNA sequence of these genes, obtained by aligning the gene sequences of the species Manihot esculenta and Ricinus communis L. Additionally, it was assessed the transferability of twenty SSR (simple sequence repeat) markers designed for Manihot esculenta, because among the species of Euphorbiaceae with more developed SSRs markers, because it is the closest relative phylogenetic species of E. heterophylla. Regarding genetic inheritance, the frequencies observed in the F1, F2, RCs and RCr did not differ significantly from the expected frequencies for a trait controlled by two dominant genes for multiple resistance and a single dominant gene for simple resistance to ALS- and PROTOX-inhibiting herbicides. The similar levels of resistance to dosage up to 2000 g i.a. ha-1 of fomesafen and dosage up to 800 g i.a. ha-1 of imazethapyr observed in F1 (heterozygous) and homozygous R biotype confirm the complete dominance of resistance to PROTOX- and ALS-inhibiting herbicides, respectively. The 0.2%BME protocol allowed the isolation of 7,083 ng μL-1 DNA, significantly (P=0.05) higher than other methods. Co-isolation of phenolic compounds was observed in FENOL and 3%BME+TB methods, but the addition of polyvinylpyrrolidone (PVP40) in the protocol extraction buffer 3%BME+TA solved this problem. The primers designed for ALS and PROTOX genes amplified but not showed no visible polymorphism in agarose gel between the S and R biotypes of E. heterophylla. Regarding the SSR transferability, ten markers were transferred to E. heterophylla, however, these six primers showed polymorphism among S and R biotypes.

Genetic resources in wild and cultured stocks of the Asian mud crab, Scylla paramamosain

The mud crab (Scylla spp.) aquaculture industry has expanded rapidly in recent years in many countries in the Indo - West Pacific (IWP) region as an alternative to marine shrimp culture because of significant disease outbreaks and associated failures of many shrimp culture industries in the region. Currently, practices used to produce and manage breeding crabs in hatcheries may compromise levels of genetic diversity, ultimately compromising growth rates, disease resistance and stock productivity. Therefore, to avoid “genetic pollution” and its harmful effects and to promote further development of mud crab aquaculture and fisheries in a sustainable way, a greater understanding of the genetic attributes of wild and cultured mud crab stocks is required. Application of these results can provide benefits for managing wild and cultured Asian mud crab populations for multiple purposes including for commercial production, recreation and conservation and to increase profitability and sustainability of newly emerging crab culture industries. Phylogeographic patterns and the genetic structure of Asian mud crab populations across the IWP were assessed to determine if they were concordant with those of other widespread taxa possessing pelagic larvae of relatively long duration. A 597 bp fragment of the mitochondrial DNA COI gene was amplified and screened for variation in a total of 297 individuals of S. paramamosain from six sampling sites across the species’ natural geographical distribution in the IWP and 36 unique haplotypes were identified. Haplotype diversities per site ranged from 0.516 to 0.879. Nucleotide diversity estimates among haplotypes were 0.11% – 0.48%. Maximum divergence observed among S. paramamosain samples was 1.533% and samples formed essentially a single monophyletic group as no obvious clades were related to geographical location of sites. A weak positive relationship was observed however, between genetic distance and geographical distance among sites. Microsatellite markers were then used to assess contemporary gene flow and population structure in Asian mud crab populations sampled across their natural distribution in the IWP. Eight microsatellite loci were screened in sampled S. paramamosain populations and all showed high allelic diversity at all loci in sampled populations. In total, 344 individuals were analysed, and 304 microsatellite alleles were found across the 8 loci. The mean number of alleles per locus at each site ranged from 20.75 to 28.25. Mean allelic richness per site varied from 17.2 to 18.9. All sites showed high levels of heterozygosity as average expected heterozygosities for all loci ranged from 0.917 – 0.953 while mean observed heterozygosity ranged from 0.916 – 0.959. Allele diversities were similar at all sites and across all loci. The results did not show any evidence for major differences in allele frequencies among sites and patterns of allele frequencies were very similar in all populations across all loci. Estimates of population differentiation (FST) were relatively low and most probably largely reflect intra – individual variation for very highly variable loci. Results from nDNA analysis showed evidence for only very limited population genetic structure among sampled S. paramamosain, and a positive and significant association for genetic and geographical distance among sample sites. Microsatellite markers were then employed to determine if adequate levels of genetic diversity has been captured in crab hatcheries for the breeding cycle. The results showed that all microsatellite loci were polymorphic in hatchery samples. Culture populations were in general, highly genetically depauperate, compared with comparable wild populations, with only 3 to 8 alleles recorded for the same loci set per population. In contrast, very high numbers of alleles per locus were found in reference wild S. paramamosain populations, which ranged from 18 to 46 alleles per locus per population. In general, this translates into a 3 to 10 fold decline in mean allelic richness per locus in all culture stocks compared with wild reference counterparts. Furthermore, most loci in all cultured S. paramamosain samples showed departures from HWE equilibrium. Allele frequencies were very different in culture samples from that present in comparable wild reference samples and this in particular, was reflected in a large decline in allele diversity per locus. The pattern observed was best explained by significant impacts of breeding practices employed in hatcheries rather than natural differentiation among wild populations used as the source of brood stock. Recognition of current problems and management strategies for the species both for the medium and long-term development of the new culture industry are discussed. The priority research to be undertaken over the medium term for S. paramamosain should be to close the life cycle fully to allow individuals to be bred on demand and their offspring equalised to control broodstock reproductive contributions. Establishing a broodstock register and pedigree mating system will be required before any selection program is implemented. This will ensure that sufficient genetic variation will be available to allow genetic gains to be sustainably achieved in a future stock improvement program. A fundamental starting point to improve hatchery practices will be to encourage farmers and hatchery managers to spawn more females in their hatcheries as it will increase background genetic diversity in culture stocks. Combining crablet cohorts from multiple hatcheries into a single cohort for supply to farmers or rotation of breeding females regularly in hatcheries will help to address immediate genetic diversity problems in culture stocks. Application of these results can provide benefits for managing wild and cultured Asian mud crab populations more efficiently. Over the long-term, application of data on genetic diversity in wild and cultured stocks of Asian mud crab will contribute to development of sustainable and productive culture industries in Vietnam and other countries in the IWP and can contribute towards conservation of wild genetic resources.

Broad Bean Stain Virus: Identification, Detectability with ELISA in Faba Bean Leaves and Seeds, Occurrence in West Asia and North Africa and Possible Wild Hosts

Abstract During a survey of faba bean viruses in West Asia and North Africa a virus was identified as broad bean stain virus (BBSV) based on host reactions, electron microscopy, physical properties and serology. An antiserum to a Syrian isolate was prepared. With this antiserum both the direct double antibody sandwich ELISA (DAS-ELISA) and dot-ELISA were very sensitive in detecting BBSV in leaf extracts, ground whole seeds and germi nated embryos. Sens it i vity was not reduced when the two-day procedure was replaced by a one-day procedure. us i ng ELISA the vi rus was detected in 73 out of 589 faba bean samples with virus-like symptoms collected from Egypt (4 out of 70 samples tested), Lebanon (6/44) , Morocco (017), Sudan (19/254), Syria (36/145) and Tunisia (8/69). This is the first report of BBSV infection of faba bean in Lebanon, Sudan, Syria and Tunisia. speci es i ndi genous to Syri a were Fourteen wild legume susceptible to BBSV infection, with only two producing obvious symptoms. The virus was found to be seed transmitted ~n Vicia palaestina.

Seed Transmission of Broad Bean Stain Virus in the Wild Legume Vicia Palestina Boiss

Abstract Seed-transmissibility of brood bean stain virus (BBSV) was investigated in a number of wild legume species. Genninating axes of seeds coliected from BBSV -infected plants were tested by the enzyme-linked immunosorbent assay (ELISA). The virus was found to be seedtransmitted in Vida pal«stina.

Wild weather hampers Brisbane’s popular CityCat services

The heavy rain falls that we have been experiencing have had their impact on the public transport system, especially the ferries. September 2010 was the Brisbane area’s wettest on record, and early to mid October has shaped up much the same. So much so that the South East Queensland’s main water storages, the Wivenhoe and Somerset Dams, which are fed by the Stanley and Brisbane Rivers’ upper catchments, have filled to capacity. SEQ Water consequently released the floodgates on the Wivenhoe Dam for the first time in almost a decade, with bipartisan support of State and Local Governments.

Wild Things

Creative non-fiction published by Voiceworks.

PCR bias Toward the wild-type k-ras and p53 sequences: Implications for PCR detection of mutations and cancer diagnosis

PCR-based cancer diagnosis requires detection of rare mutations in k- ras, p53 or other genes. The assumption has been that mutant and wild-type sequences amplify with near equal efficiency, so that they are eventually present in proportions representative of the starting material. Work on factor IX suggests that this assumption is invalid for one case of near- sequence identity. To test the generality of this phenomenon and its relevance to cancer diagnosis, primers distant from point mutations in p53 and k-ras were used to amplify wild-type and mutant sequences from these genes. A substantial bias against PCR amplification of mutants was observed for two regions of the p53 gene and one region of k-ras. For k-ras and p53, bias was observed when the wild-type and mutant sequences were amplified separately or when mixed in equal proportions before PCR. Bias was present with proofreading and non-proofreading polymerase. Mutant and wild-type segments of the factor V, cystic fibrosis transmembrane conductance regulator and prothrombin genes were amplified and did not exhibit PCR bias. Therefore, the assumption of equal PCR efficiency for point mutant and wild-type sequences is invalid in several systems. Quantitative or diagnostic PCR will require validation for each locus, and enrichment strategies may be needed to optimize detection of mutants.