Boro afeta o crescimento e a ultra-estrutura da mamoneira

A mamoneira é uma oleaginosa com grande potencial para a geração de renda na agricultura familiar e para produção de matéria prima para a indústria química e setor energético brasileiro, especialmente em regiões do semi-árido nordestino. A deficiência de boro (B) ocorre de forma generalizada no Brasil e a aplicação excessiva deste micronutriente pode causar toxicidade. Este estudo avalia o desenvolvimento e os efeitos ultra-estruturais de deficiência e toxicidade de boro em mamoneira. O experimento foi realizado em condições de casa de vegetação, com vasos de 10 L de solução nutritiva. Foram utilizados três tratamentos: testemunha (sem B); 0,27 e 5,40 mg L-1 B, uma planta por vaso, em delineamento experimental inteiramente ao acaso com três repetições. A produção de matéria seca de cada parte da planta foi avaliada e o teor de boro determinado. Foram observados os efeitos morfológicos e as alterações na ultra-estrutura celular nas folhas e pecíolos, através da técnica de microscopia eletrônica de transmissão e varredura. A produção de matéria seca da mamoneira foi afetada em condições de deficiência de boro, mas não em condições de toxicidade (5,4 mg L-1 B). Neste último tratamento foram constatadas cloroses nos bordos de folhas velhas e ausência de grânulos de amido. Na omissão de boro, as plantas apresentaram deformação de folhas novas, morte do meristema apical, engrossamento da lamela média, ausência de grânulos de amido nos cloroplastos e desorganização dos vasos condutores do pecíolo. O desenvolvimento e a produção da mamoneira são afetados em condições de deficiência de boro mas não na condição de toxicidade.The cultivation of oleaginous plants like the castor bean guarantees employment for agricultural families and can contribute in energy and chemical sectors, especially in the northeastern semi-arid regions of Brazil. Boron (B) deficiency is a widespread nutritional disorder despite the fact that various anthropogenic sources with high B content may increase soil B to toxic levels for plants. The present study was designed to investigate the ultrastructural effects of boron deficiency and toxicity on castor bean plants which were grown under greenhouse condition using plastic containers with 10 L of nutrient solution. Boron treatments comprised: control (no B); 0.27 mg L-1, 5.40 mg L-1 B pots (one plant per pot), tested in a completely randomized design with three replicates. The dry matter of all plant parts and B concentration were determined. Cellular ultrastructure was evaluated by transmission and scanning electron microscopy on samples of leaves and petioles. Dry matter yield was affected by the B absence treatment but there was no difference for the 5.4 mg L-1 B (toxic conditions) treatment. A marginal leaf burn at edge and tips of oldest leaves and absence of starch granules in chloroplasts were noted for the B toxicity treatment. The deformation of the youngest leaves, the death of the apical meristem as well as the swelling of the middle lamella, absence of starch granules in chloroplasts and petiole vessels untidily were observed in the B absent treatment. It is concluded that the production and development of castor bean plants is affected by boron deficiency, but not for boron toxicity conditions

Alterações na ultra-estrutura de genótipos de soja em resposta ao fornecimento de manganês em solução nutritiva

The deleterious effects of Mn stress on many species have been studied, mainly concerning biochemical, physiological and growth parameters of plants. However, there are few studies relating the anatomical and ultrastructural changes in response to manganese (Mn) nutritional disorders, This study examined the leaf ultrastructure of Mn-inefficient (IAC-15, Santa Rosa) and Mn-efficient (IAC-Foscarin 31) soybean (Glycine max L.) genotypes in response to three rates of Mn (0.5, 2 and 200 µmol L-1) in the nutrient solution. Symptoms of Mn deficiency developed 12 days after transplanting in IAC-15 and Santa Rosa, followed by IAC-Foscarin 31 on the 15th day. Only IAC-15 and Santa Rosa leaves showed symptoms of Mn toxicity. The Mn concentration in leaves ranged from 8.6 (deficiency) to 886.3 mg kg-1 d.w. (toxicity). There were no changes either in stomata length or stomata number per unit of leaf surface. Cytoplasm disorganization was observed in IAC-15 under Mn-excess. In this case, the cytoplasm was amorphous, densely stained and extensively disorganized, with increased vacuolation. Mn effects were not found in mitochondria and nucleus in any of the genotypes tested. Under all Mn concentrations, many lipid globules were observed in the IAC15 chloroplasts. There was an increase in the number of plastids as well as in the size of starch grains within IAC-Foscarin 31 chloroplasts as Mn concentration in the nutrient solution increased. Genotypes had marked differences in the ultrastructure organization, mainly in leaf chloroplasts grown under conditions of both Mn deficiency and toxicity (the most sensitive genotype was IAC-15).Os efeitos negativos provocados tanto pela deficiência quanto pela toxidez de manganês (Mn) no desenvolvimento das plantas têm sido avaliados, considerando-se os aspectos bioquímicos e produtivos da parte aérea, particularmente, onde os sintomas visuais são manifestados. Entretanto, há poucas informações na literatura abordando as alterações anatômicas e de ultra-estrutura, em relação ao suprimento de Mn. Os objetivos do presente estudo foram avaliar os efeitos do fornecimento de três doses de Mn (0,5; 2 e 200 µmol L-1), em solução nutritiva, nas ultra-estruturas de folhas de cultivares de soja Glycine max (L.): Santa Rosa, IAC-15 e IAC-Foscarin 31, contrastantes quanto à aquisição e ao uso do Mn. Os sintomas visuais de deficiência foram observados primeiramente em Santa Rosa e IAC-15 (ineficientes), os únicos a exibirem sintomas de toxidez. As concentrações de Mn nas folhas com sintomas variaram de 8,6 (deficiência) a 886,3 mg kg-1 (toxidez). Não houve alterações no comprimento e no número de estômatos nos limbos foliares. Em condição de toxidez, constatou-se no IAC-15, citoplasma desorganizado, vacuolado em excesso e denso evidenciando alterações nas membranas dos tilacóides. Não ocorreram alterações ultra-estruturais nas mitocôndrias e no núcleo das células dos três genótipos. Constatou-se presença de glóbulos de lipídios nos cloroplastos do cultivar IAC-15, em todas as condições de fornecimento de Mn. Houve aumento no número de plastídeos e grãos de amido, bem como no tamanho destes no IAC-Foscarin 31 com o suprimento de Mn. Os genótipos, tanto na condição de deficiência quanto de excesso, exibiram distintos graus de organização das ultraestruturas, notadamente, os cloroplastos. O IAC-15 exibiu maiores alterações das ultra-estruturas em função das desordens nutricionais em manganês

Sintomas de deficiência e acúmulo de micronutrientes na mamoneira cultivada em solução nutritiva

Castor bean is a nutrient-demanding species, but there is still little information on its micronutrient requirements. The objectives of this study were to evaluate the effects of levels of B (2.5, 12.5 and 25.0 µmol L-1), Cu (0.05, 0.25 and 0.50 µmol L-1), Mn (0.2, 1.0 and 2.0 µmol L-1) and Zn (0.2, 1.0 and 2.0 µmol L-1) in a nutrient solution on plant B, Cu, Mn and Zn concentrations and uptake, vegetative growth and fruit yield of castor bean "Iris", grown in greenhouse. The experiment was arranged in a completely randomized block design with three replicates. The first deficiency symptoms were observed for B, followed by Zn, Cu and Mn. The main changes in the cell ultrastructure due to lack of B were thickening of the cell walls and middle lamellae, distorted chloroplasts and tightly stacked thylakoids, besides the absence of starch grains. The Mn, Zn and Cu deficiencies led to disruption of chloroplasts, disintegration of thylakoids and absence of amyloplasts. The concentration and uptake of B, Cu, Mn, and Zn in castor bean plants increased with micronutrient supply in the solution. Fruit yield was drastically reduced by B and Mn deficiencies. On the other hand, the dry matter yield of the shoot and root of castor bean plants was not. In the treatment with full nutrient solution, the leaves accumulated 56 and 48 % of the total B and Mn taken up by the plants, respectively, and the seeds and roots 85 and 61 % of the total Cu and Zn taken up, respectively. This shows the high demand of castor bean Iris for B and Mn for fruit yield

A CRIANÇA E O NÚMERO

Ensinar número para crianças é uma tarefa difícil, uma vez que o educador necessita de sensibilidadepara detectar as necessidades no aprendizado do aluno no processo de conservação do número, ou seja, que oaluno compreenda que o arranjo diferenciado na colocação de objetos sobre a mesa não altera a quantidade. Asmaneiras de ensinar, através da busca pela construção do conceito de número pela criança, devem respeitar umaordem hierárquica de desenvolvimento que toda criança possui. Essa ordem passa pela natureza do número quese desenvolve sob três tipos de conhecimento: conhecimentos físicos – conhecimento das propriedades que estãonos objetos na realidade externa, e podem ser conhecidas pela observação; conhecimento lógico matemático – conhecimentoda existência de diferença entre dois objetos, criada mentalmente pelo indivíduo; conhecimento social– convenções criadas, como as palavras um, dois, três, assim como o ato de dizer bom dia. Todo esse ensinamentotem como objetivo dar autonomia para a criança, diminuindo sua dependência dos adultos e é nos jogos e nasbrincadeiras em sala de aula que encontramos as melhores maneiras para a criança adquirir esses ensinamentos e,por consequência, sua autonomia

Somatic embryogenesis and the effect of particle bombardment on banana Maçã regeneration

Neste trabalho é descrito um método de regeneração de plantas, a partir de células de bananeira, em suspensão, e o efeito da biobalística no potencial regenerativo. Embriões somáticos foram obtidos de inflorescências masculinas de bananeira cv. Maçã (grupo AAB) por meio de embriogênese indireta. Parte dos calos (40%) apresentou características embriogênicas (não-friáveis, compactas e amareladas). Suspensões celulares obtidas desses calos continham pequenas massas celulares, com citoplasmas ricos em grânulos de amido, núcleos grandes e nucléolos densos. Após quatro meses, embriões somáticos começaram a se desenvolver. O número máximo de plantas regeneradas ocorreu 45–60 dias após a formação dos embriões. No primeiro experimento foram regeneradas 401 plantas. No segundo, 399 plantas foram obtidas de uma suspensão celular 6 meses mais velha do que a do primeiro experimento. Transformações celulares com uma das três construções plasmidiais utilizadas, que continham o gene uid-A, resultaram em fortes sinais de expressão cinco dias após as transformações; todavia, o número de plantas regeneradas foi muito menor do que o observado no material não bombardeado.A plant regeneration method with cell suspension cultures of banana, and the effect of biobalistic on regeneration potential are described in this report. Somatic embryos of banana were obtained from indirect embryogenesis of male inflorescence of banana cultivar Maçã (AAB group). Part of the calluses formed (40%) showed embryogenic characteristics (nonfriable, compact and yellow color). The cell suspension, originated from embryogenic calluses, contained clusters of small tightly packed cells with dense cytoplasms, relatively large nuclei and very dense nucleoli. After four months of culture, somatic embryos started to regenerate. The maximum number of regenerated plants was observed between 45 and 60 days after embryo formation. In the first experiment, 401 plants were regenerated from approximately 10 mL of packed cells. In the second experiment, 399 plants were regenerated from a cell suspension six months older than that of the first experiment. Cell transformation using particle bombardment with three different plasmid constructions, containing the uid-A gene, resulted in a strong GUS expression five days after bombardment; however, plant regeneration from bombarded cells was much lower than nonbombarded ones

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Not available

Na presente tese foi estudado o local de replicação do RNA do vírus do Anel do Pimentão (VAP) associando-se as técnicas de auto-radiografia e microscopia eletrônica. Tecidos foliares de Nicotiana tabacum L, var. Turkish NN sadios e com VAP foram incubados com Actinomicina D (AMD) ou agua e a seguir tratadas com uridina tritiada (atividade específica 29,2 curies/m mol) durante três intervalos de tempo, 3, 5 e 9 horas. Depois de fixados com glutaraldeido e ácido ósmico foram desidratados com acetona 30, 50, 70, 90 e 100% e incluídos em resina Epon. Os cortes ultrafinos e semifinos foram cobertos com emulsão fotográfica e apôs tempo de exposição adequado foram revelados e examinados. A produção de grãos de prata reduzida (grãos ) devido a incorporação de uridina -5-3H (U-5-3H) no RNA permitiu contagens que, analisadas quantitativamente, serviram para identificar o local de replicação do RNA viral. Os resultados obtidos indicaram que: 1. O efeito dos tratamentos utilizados sobre as áreas médias das secções das células foliares e as áreas médias de seus constituintes não apresentam diferença estatística significativa a nível de 1% de probabilidade. 2. A densidade dos grãos de prata da célula afetada pelo VAP e tratada com água indica que a síntese de RNA sofre uma redução no período de 3 a 5 horas de incubação com U-5-3H e que a taxa de redução no período de 5 a 9 horas é semelhante entre célula doente e sadia. 3. O tratamento dos tecidos foliares sadios e doentes com AMD revelou que a ação do antibiótico foi seletiva no sentido de inibir a polimerase dependente do DNA e não a replicasse do RNA viral, permitindo acompanhar com melhor aproximação o curso da biossíntese do RNA do VAP. 4. O estudo do comportamento individual de três regiões da célula sadia ao tratamento com AMD, mostrou, pela comparação dos números de grãos de prata por unidade de área, que a atividade de síntese do RNA no nucléolo foi a mais inibida pelo antibiótico, seguindo-se a do citoplasma e a do núcleo. 5. As densidades dos grãos de prata das organelas da célula afetada tratada com AMD e corrigidas com respeito às densidades da célula sadia inibida com AMD, mostraram que o curso da biossíntese do ácido nucléico no núcleo (excluindo o nucléolo) e no citoplasma é bastante semelhante, diferindo do processo biossintético do RNA no nucléolo. 6. Examinando as taxas de síntese do RNA da célula afetada pelo VAP, tratada com AMD e corrigida com os respectivos valores da célula sadia nas mesmas condições e no período de 3 a 5 horas, observou-se que a taxa de síntese no nucléolo é aproximadamente três vezes a do citoplasma e a do núcleo sem nucléolo. 7. Os dados da tese sugerem que embora alguma síntese do RNA ou ácidos nucléicos devidos a presença do VAP possa ocorrer no núcleo da célula infectada, o nucléolo é o local principal da biossíntese do RNA do VAP. 8. As auto-radiografias revelaram também que a translocação do RNA marcado do VAP já pode ser observada nas proximidades do mitocôndria no período de 5 horas de tratamento com U-5-3H.Location of the replication of the RNA of the Virus Anel do Pimentão (VAP) has been studied using both autoradiograph and electron microscope techniques. Foliar tissues of Nicotiana tabacum L. var. Turkish NN, healthy and infected with VAP, were incubated with Actinomicina D (AMD),or water and then treated with tritiated uridine (specific activity 29.2 Ci/mmol) during three different time intervals - 3, 5 and 9 hours. After being fixed with glutaraldehyde and osmic acid they were dehydrated with 30, 50, 70, 90 and 100% acetone and embedded in Epon resin. The ultra-thin and semi-thin sections were covered with photographic emulsion and after adequate exposure they were developed and examined. The production of reduced silver grains (grains) due to the incorporation of uridine-5-3H (U-5-3H) in the RNA, made possible countings which, analysed quantitatively, helped in the identification of the location of the replication of the virus RNA. Results obtained indicated that: 1. The effect of the treatments on the area of the foliar cells and on the area of their constituents presented no significant difference at a level of 1% probability. 2. The silver grain density on VAP infected cell treated with water presented some decrease during 3 - 5 hours incubation with U-5-3H and similar behavior during 5-9 hours between healthy and diseased cells. 3. Treatment of healthy and infected foliar tissues with AMD revealed that the action of the antibiotic was selective as far as inhibition of the DNA dependent polymerase and not on the replicase of the virus RNA, allowing to follow with a better approximation, the development of the RNA biosynthesis of the VAP. 4. Study of the response of three regions of a healthy cell to treatment with AMD indicated that the most inhibited activity was the RNA synthesis in the nucleolus, followed by that of the cytoplasm and of the nucleus. 5. The grain density obtained for regions of an infected cell treated with AMD and corrected in relation to the densities of a healthy cell inhibited with AMD, indicated that the biosynthesis of the nucleic acid in the nucleus excluding the nucleolus, and in the cytoplasm is identical, differing from the biosynthetic process of the RNA in the nucleolus. 6. When studying the rate of the synthesis of the RNA in a cell infected with VAP and treated with AMD and corrected according to the respective values for a healthy cell under same conditions and for a period of 3-5 hours, it was observed that the rate of synthesis of the nucleolus is approximately three times that of the cytoplasm and of the nucleus without nucleolus. 7. The data presented suggest that, although some synthesis of the RNA or nucleic acids due to the presence of VAP can occur in the nucleus of an infected cell, the nucleolus is the main place of the biosynthesis of the RNA of the VAP. 8. The autoradiographs revealed that the translocation of the labelled RNA of the VAP can already be noted close to the mitochondria in a period of 5 hours treatment with U-5-3H

Achromobacter insolitus and Zoogloea ramigera associated with wheat plants (Triticum aestivum)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)This study reports for the first time the presence of diazotrophic bacteria belonging to the genera Achromobacter and Zoogloea associated with wheat plants. These bacterial strains were identified by the analysis of 16S rDNA sequences. The bacterium IAC-AT-8 was identified as Azospirillum brasiliense, whereas isolates IAC-HT-11 and IAC-HT-12 were identified as Achromobacter insolitus and Zoogloea ramigera, respectively. A greenhouse experiment involving a non-sterilized soil was carried out with the aim to study the endophytic feature of these strains. After 40 days from inoculation, all the strains were in the inner of roots, but they were not detected in soil. In order to assess the location inside wheat plants, an experiment was conducted under axenic conditions. Fifteen days after inoculation, preparations of inoculated plants were observed by the scanning electron microscope, using the cryofracture technique, and by the transmission electron microscope. It was observed that all isolates were present on the external part of the roots and in the inner part at the elongation region, in cortex cells, but not in the endodermis or in the vascular bundle region. No colonizing bacterial cells were observed in wheat leaves.44811071112Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES