Federal University of Roraima

About: Federal University of Roraima is a based out in . It is known for research contribution in the topics: Population & Thermogravimetry. The organization has 981 authors who have published 1218 publications receiving 7849 citations. The organization is also known as: Federal University of Roraima.

Gene expression analysis reveals important pathways for drought response in leaves and roots of a wheat cultivar adapted to rainfed cropping in the Cerrado biome

Abstract: Drought limits wheat production in the Brazilian Cerrado biome. In order to search for candidate genes associated to the response to water deficit, we analyzed the gene expression profiles, under severe drought stress, in roots and leaves of the cultivar MGS1 Alianca, a well-adapted cultivar to the Cerrado. A set of 4,422 candidate genes was found in roots and leaves. The number of down-regulated transcripts in roots was higher than the up-regulated transcripts, while the opposite occurred in leaves. The number of common transcripts between the two tissues was 1,249, while 2,124 were specific to roots and 1,049 specific to leaves. Quantitative RT-PCR analysis revealed a 0.78 correlation with the expression data. The candidate genes were distributed across all chromosomes and component genomes, but a greater number was mapped on the B genome, particularly on chromosomes 3B, 5B and 2B. When considering both tissues, 116 different pathways were induced. One common pathway, among the top three activated pathways in both tissues, was starch and sucrose metabolism. These results pave the way for future marker development and selection of important genes and are useful for understanding the metabolic pathways involved in wheat drought response.

Cyberlindnera xylosilytica sp. nov., a xylitol-producing yeast species isolated from lignocellulosic materials.

Abstract: Independent surveys of yeasts associated with lignocellulosic-related materials led to the discovery of a novel yeast species belonging to the Cyberlindnera clade (Saccharomycotina, Ascomycota). Analysis of the sequences of the internal transcribed spacer (ITS) region and the D1/D2 domains of the large subunit rRNA gene showed that this species is related to C. japonica, C. maesa and C. easanensis. Six isolates were obtained from different sources, including rotting wood, tree bark and sugar cane filter cake in Brazil, frass from white oak in the USA and decayed leaf in Taiwan. A novel species is suggested to accommodate these isolates, for which the name C. xylosilytica sp. nov. is proposed. The type strain of C. xylosilytica sp. nov. is NRRL YB-2097T ( = CBS 13984T = UFMG-CM-Y347T) and the allotype is UFMG-CM-Y409 ( = CBS 14083). The novel species is heterothallic and complementary mating types are represented by the type and allotype strains. The MycoBank number is MB 811428.

Tomato yield and potassium concentrations in soil and in plant petioles as affected by potassium fertirrigation

Abstract: - Tomato (Lycopersicon esculentum Mill.) cv. Santa Clara was grown on a silt clay soilwith 46 mg dm -3 Mehlich 1 extractable K, to evaluate the effects of trickle-applied K rates on fruityield and to establish K critical concentrations in soil and in plant petioles. Six potassium rates (0, 48,119, 189, 259 and 400 kg ha -1 K) were applied in a randomized complete block design with fourreplications. Soil and plant K critical levels were determined at two plant growth stages (at the beginningof the second and fourth cluster flowering). Total, marketable and weighted yields increased with Krates, reaching their maximum of 86.4, 73.4, and 54.9 ton ha -1 at 198, 194, and 125 kg ha K , respectively.At the first soil sampling date K critical concentrations in the soil associated with K rates for maximummarketable and weighted yields were 92 and 68 mg dm -3 , respectively. Potassium critical concentrationsin the dry matter of the petioles sampled by the beginning of the second and fourth cluster floweringtime, associated with maximum weighted yield, were 10.30 and 7.30 dag kg

Amazon tree dominance across forest strata

Abstract: The forests of Amazonia are among the most biodiverse plant communities on Earth. Given the immediate threats posed by climate and land-use change, an improved understanding of how this extraordinary biodiversity is spatially organized is urgently required to develop effective conservation strategies. Most Amazonian tree species are extremely rare but a few are common across the region. Indeed, just 227 ‘hyperdominant’ species account for >50% of all individuals >10 cm diameter at 1.3 m in height. Yet, the degree to which the phenomenon of hyperdominance is sensitive to tree size, the extent to which the composition of dominant species changes with size class and how evolutionary history constrains tree hyperdominance, all remain unknown. Here, we use a large floristic dataset to show that, while hyperdominance is a universal phenomenon across forest strata, different species dominate the forest understory, midstory and canopy. We further find that, although species belonging to a range of phylogenetically dispersed lineages have become hyperdominant in small size classes, hyperdominants in large size classes are restricted to a few lineages. Our results demonstrate that it is essential to consider all forest strata to understand regional patterns of dominance and composition in Amazonia. More generally, through the lens of 654 hyperdominant species, we outline a tractable pathway for understanding the functioning of half of Amazonian forests across vertical strata and geographical locations. Most Amazon tree species are rare but a small proportion are common across the region. The authors show that different species are hyperdominant in different size classes and that hyperdominance is more phylogenetically restricted for larger canopy trees than for smaller understory ones.

Flow-by-flow chemical stratigraphy and evolution of thirteen Serra Geral Group basalt flows from Vista Alegre, southernmost Brazil

Abstract: The geochemical characterization of thirteen Serra Geral Group flows in the Vista Alegre region (RS-SC), southern Brazil, displays the homogeneous basaltic composition near 50 wt.% SiO2. Each of the five basal flows (Pitanga-type, high-Ti/Y ~600, TiO2 > 3 wt.%) and eight upper flows (Paranapanema-type, medium Ti/Y ~400, TiO2 > 2 wt.%) can be identified from their chemical composition; sets of flows have parallel variation in chemical composition. The flow-by-flowcorrelation in four sections shows the horizontal position of the flows in three profiles and an approximately 200-m downdrop of the Itapiranga block with respect to the Frederico Westphalen block. The world-class amethyst geode mineralization and the systematic presence of native copper in the basalts make the correlation of great geological and economic significance.