Efeito de doses de nitrogênio em cobertura em variáveis biométricas e de produção em híbridos de milho.

Resumo: Com o objetivo de avaliar a adubação nitrogenada em cobertura em variáveis biométricas e de produção de diferentes híbridos de milho, conduziu-se ensaio em condições de campo em Jaboticabal, SP. Antes da instalação do experimento foi realizada amostragem de solo na camada 0-20 cm para verificação da fertilidade do solo e ainda realizou-se a adubação de semeadura, que consistiu em 300 kg ha-1 do formulado 4-20-20. Os tratamentos foram dois genótipos híbridos simples, AS1522 e AS1596 submetidos a quatro níveis de N em cobertura: zero, metade da padrão, padrão e duas vezes a padrão. O delineamento foi em blocos ao acaso, com três repetições. A semeadura foi realizada manualmente, e quando as plantas atingiram estágio de maturidade fisiológica foram avaliadas as variáveis altura, diâmetro do colmo, produção de grãos, número de grãos por espiga e número de fileiras de grãos por espiga. Os dados foram analisados utilizando-se o teste F e, quando significativos foi realizado teste de comparação de médias. Há diferença entre os híbridos de milho em função das doses de nitrogênio aplicadas em cobertura para produção de grãos e eficiência agronômica. O material AS1596 apresentou superioridade na produção de grãos e eficiência agronômica em relação ao genótipo AS1522. [Effect of nitrogen topdressing levels on biometric variables and on production of corn hybrids]. Abstract: Aiming to evaluate the nitrogen topdressing on biometric variables and production of different corn hybrids, an experiment was conducted under field conditions in Jaboticabal, SP. Before carrying out the experiment, soil sampling in the layer 0-20 cm was performed for soil fertility verification, also it was performed the sowing fertilization, which consisted of the 300 kg ha-1 formulated 4-20-20. The treatments consisted of two simple hybrid genotypes, AS1522 and AS1596, subjected to four nitrogen level: zero, half the standard, standard and twice the standard. The experimental was a randomized complete block design with three replications. The sowing was done manually, and when the plants reached stage of physiological maturity, parameters such as height, stem geometry, grain yield, number of grains per spike and number of grain rows per ear were evaluated. The data were analyzed through the F test, and when significant, it was carried out an average comparison. There is difference between the hybrids on the basis of nitrogen topdressing for grain yield and agronomic efficiency. The material AS1596 showed superiority in grain yield and agronomic efficiency in relation to genotype AS1522

Qualidade industrial de cultivares de trigo e triticale submetidos à adubação nitrogenada no sistema de plantio direto.

O presente trabalho foi desenvolvido nos anos agrícolas de 2004 e 2005, no município de Selvíria (MS), com o objetivo de avaliar a influência de doses de nitrogênio (N) em cobertura nas características industriais de cultivares de trigo e triticale, em sistema de plantio direto. O delineamento experimental foi o de blocos ao acaso, com parcelas subdivididas, com 30 tratamentos constituídos pela combinação de seis cultivares nas parcelas, sendo cinco cultivares de trigo (IAC 364, IAC 370, Embrapa 22, BRS 210 e BRS 207) e um de triticale (IAC 3), e cinco doses de N em cobertura (0, 30, 60, 90 e 120 kg ha-1) nas subparcelas, com quatro repetições. Em função dos resultados obtidos, o peso hectolítrico do triticale foi inferior ao dos cultivares de trigo, com a adubação nitrogenada proporcionando redução nesse componente; o número de queda foi adequado, sendo pouco afetado pela adubação nitrogenada; a relação P/L da farinha, de forma geral foi elevada, podendo prejudicar a aceitação comercial de farinha para panificação; a adubação nitrogenada em cobertura incrementou a força geral do glúten (W), bem como o teor de proteína da farinha e reduziu a relação P/L, influenciando positivamente na qualidade da farinha para panificação; a farinha de triticale não foi adequada para fins de panificação, por sua reduzida força geral do glúten.The work was developed in season cropping 2004 and 2005 in Selvíria county (MS), Brazil, with aim of evaluate the effect of different rates of nitrogen (N) in side dress on the industrial characteristics of the cultivars of wheat and triticale in no-till system. The completely randomize design was used with split plots with 30 treatments, consisting of the six combination of cultivars in plots, being five cultivars of wheat (IAC 364, IAC 370, Embrapa 22, BRS 210 and BRS 207) and one of triticale (IAC 3), and five rates of N in side dress (0, 30, 60, 90 and 120 kg ha-1) in subplots, with four replicatons. In function of the results gotten, the hectoliter weight of triticale was inferior to the ones of the wheat, with the nitrogen fertilization providing reduction in this component; the falling number is adjusted, not being affected for the nitrogen fertilization; relation P/L of the flour of general form is raised, harming the commercial flour acceptance for bread-making; the nitrogen fertilization in covering develops the gluten strength (W) as well as the protein content of the flour and reduces relation P/L positively, influencing in the quality of the flour for bread-making; the flour of triticale is not adjusted for end of bread-making for its reduced gluten strength

In Search of Possible Associations between Planetary Nebulae and Open Clusters

We consider the possibility of cluster membership for 13 planetary nebulae that are located in close proximity to open clusters lying in their lines of sight. The short lifetimes and low sample size of intermediate-mass planetary nebulae with respect to nearby open clusters conspire to reduce the probability of observing a true association. Not surprisingly, line of sight coincidences almost certainly exist for 7 of the 13 cases considered. Additional studies are advocated, however, for 6 planetary nebula/open cluster coincidences in which a physical association is not excluded by the available evidence, namely M 1-80/Berkeley 57, NGC 2438/NGC 2437, NGC 2452/NGC 2453, VBRC 2 & NGC 2899/IC 2488, and HeFa 1/NGC 6067. A number of additional potential associations between planetary nebulae and open clusters is tabulated for reference purposes. It is noteworthy that the strongest cases involve planetary nebulae lying in cluster coronae, a feature also found for short-period cluster Cepheids, which are themselves potential progenitors of planetary nebulae.Comment: Accepted for publication in PASP (December 2007

De novo transcriptome assembly of sugarcane leaves submitted to prolonged water-deficit stress.

ABSTRACT. Sugarcane production is strongly influenced by drought, which is a limiting factor for agricultural productivity in the world. In this study, the gene expression profiles obtained by de novo assembly of the leaf transcriptome of two sugarcane cultivars that differ in their physiological response to water deficit were evaluated by the RNA-Seq method: drought-tolerant cultivar (SP81-3250) and drought-sensitive cultivar (RB855453). For this purpose, plants were grown in a greenhouse for 60 days and were then submitted to three treatments: control (-0.01 to -0.015 MPa), moderate water deficit (-0.05 to -0.055 MPa), and severe water deficit (-0.075 to -0.08 MPa). The plants were evaluated 30, 60, and 90 days after the beginning of treatment. Sequencing on an Illumina platform (RNA-Seq) generated more than one billion sequences, resulting in 177,509 and 185,153 transcripts for the tolerant and sensitive cultivar, respectively. These transcripts were aligned with sequences from Saccharum spp, Sorghum bicolor, Miscanthus giganteus, and Arabidopsis thaliana available in public databases. The differentially expressed genes detected during the prolonged period of water deficit permit to increase our understanding of the molecular patterns involved in the physiological response of the two cultivars. The tolerant cultivar differentially expressed a larger number of genes at 90 days, while in the sensitive cultivar the number of differentially expressed genes was higher in 30 days. Both cultivars perceived the lack of water, but the tolerant cultivar responded more slowly than the sensitive cultivar. The latter requires rapid activation of different water-deficit stress response mechanisms for its survival. This rapid activation of metabolic pathways in response to water stress does not appear to be the key mechanism of drought tolerance in sugarcane. There is still much to clarify on the molecular and physiological pattern of plants in response to drought.Article gmr16028845

Respostas fisiológicas e enzimáticas no milho sob diferentes concentrações de nitrogênio.

O estudo de aspectos químicos e bioquímicos associados ao desenvolvimento das diferentes partes das plantas permite a observação e o entendimento de uma série de reações que levam à produção de fitomassa e grãos pela cultura de milho. Assim, objetivou-se estudar a diferença na eficiência de uso do nitrogênio nas raízes e parte aérea em dois genótipos de milho, na fase inicial de crescimento das plantas e avaliar as respostas bioquímico-fisiológicas desses órgãos quando as plantas são submetidas a distintas doses de N em condições hidropônicas

de novo assembly and transcriptome analysis of sugarcane leaves from contrasting varieties submited to prolonged water stress.

Sugarcane is an important crop, major source of sugar and alcohol, accounting for two-thirds of the world's sugar production. In Brazil, the sugarcane culture has expanded to areas with prolonged drought seasons, which is constraining its production. In order to identify genes and molecular process related to sugarcane drought tolerance, we performed de novo assembly and transcriptome analysis of two sugarcane genotypes, one tolerant and other sensitive to water stress, submitted to three water deficit condition (30, 60 and 90 days). The de novo assembly of leaves transcriptome was performed using short reads from Illumina RNA-Seq platform, which produced more than 1 billion reads, which were assembled into 177,509 and 185,153 transcripts sequences for the tolerant and sensitive cultivars, respectively. These transcripts were aligned with Sorghum bicolor, Miscanthus giganteus, Arabidopsis thaliana sequences and sugarcane sequences available in public databases. This analysis allowed the identification of a set of sugarcane genes shared with other species, as well as led to the identification of novel transcripts not cataloged yet. Differential expression analysis between genotypes and among days of water deficit were performed with EdgeR and DESeq. The differentially expressed genes were annotated and categorized using Blast2GO. The terms "enzyme regulator" and "transcription regulator" were highlighted within the differentially expressed genes between the contrasting cultivars, suggesting the importance of gene regulation during water deficit. This study found new molecular patterns, which provided hypotheses on plant response to drought and provided important information about genes involved in drought tolerance response.PAG 2016. Pôster P0792

Investigating potential planetary nebula/cluster pairs

Fundamental parameters characterizing the end-state of intermediate-mass stars may be constrained by discovering planetary nebulae (PNe) in open clusters (OCs). Cluster membership may be exploited to establish the distance, luminosity, age, and physical size for PNe, and the intrinsic luminosity and mass of its central star. Four potential PN-OC associations were investigated, to assess the cluster membership for the PNe. Radial velocities were measured from intermediate-resolution optical spectra, complemented with previous estimates in the literature. When the radial velocity study supported the PN/OC association, we analyzed if other parameters (e.g., age, distance, reddening, central star brightness) were consistent with this conclusion. Our measurements imply that the PNe VBe3 and HeFa1 are not members of the OCs NGC5999 and NGC6067, respectively, and likely belong to the background bulge population. Conversely, consistent radial velocities indicate that NGC2452/NGC2453 could be associated, but our results are not conclusive and additional observations are warranted. Finally, we demonstrate that all the available information point to He2-86 being a young, highly internally obscured PN member of NGC4463. New near-infrared photometry acquired via the Vista Variables in the Via Lactea ESO public survey was used in tandem with existing UBV photometry to measure the distance, reddening, and age of NGC4463, finding d=1.55+-0.10 kpc, E(B-V)=0.41+-0.02, and tau=65+-10 Myr, respectively. The same values should be adopted for the PN if the proposed cluster membership will be confirmed.Comment: Accepted for publication in A&

Plant ecology meets animal cognition: impacts of animal memory on seed dispersal

We propose that an understanding of animal learning and memory is critical to predicting the impacts of animals on plant populations through processes such as seed dispersal, pollination and herbivory. Focussing on endozoochory, we review the evidence that animal memory plays a role in seed dispersal, and present a model which allows us to explore the fundamental consequences of memory for this process. We demonstrate that decision-making by animals based on their previous experiences has the potential to determine which plants are visited, which fruits are selected to be eaten from the plant and where seeds are subsequently deposited, as well as being an important determinant of animal survival. Collectively, these results suggest that the impact of animal learning and memory on seed dispersal is likely to be extremely important, although to date our understanding of these processes suffers from a conspicuous lack of empirical support. This is partly because of the difficulty of conducting appropriate experiments but is also the result of limited interaction between plant ecologists and those who work on animal cognition