Search

Copyright of Nativa is the property of Revista Nativa and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ABSTRACT: The present study assessed the influence of the preceding crop (crotalaria or corn) on the bromatological, digestibility and microbiological aspects of the EMBRAPA 139 black oat hay (Avena strigosa) cultivar. A randomized block design was used, with subplots divided according to time, whereby the preceding crop (crotalaria or corn) was allocated to the main plot and hay storage times (baling, 30, 60 and 90 days of storage) to the subplots, with five repetitions. Crotalaria as predecessor resulted in lower indigestible fiber and higher protein contents in black oat hay, both in acid detergent, as well as higher pH. Corn as the preceding crop provided better hay digestibility due to lower neutral detergent insoluble protein content and higher in vitro neutral detergent fiber digestibility. The preceding crop did not significantly affect the drying time of forage and the microorganism population.

Farmers in Indonesia generally spray herbicides to control weeds and use tillage during the early stages of crop cultivation; consequently, these activities affect the weed composition and diversity. This study aimed to evaluate the dominance and diversity index of weeds and obtain abundance correlations according to the soil chemical characteristics, as well as the effect of the ammonium glufosinate herbicide, in different tillage systems. A non-factorial randomized block design was used, consisting of no-tillage (NT), 1-time tillage (T1) and 2-times tillage (T2), with three replications. The Cyperus rotundus and Ageratum conyzoides weed species were dominant in the tillages. The diversity indices were 2.261, 2.196 and 2.234 (moderate/stable condition), respectively for the NT, T1 and T2. For T2, there were increases of 2.82-folds, 41 populations and 2.43-folds, respectively for A. conyzoides,Cynodon dactylon and Euphorbia heterophylla, when compared to NT, while a decrease was observed in grasses for T1 and T2 (50.71 and 26.05 %, respectively). Moreover, there was a positive and significant correlation for E. heterophylla according to the soil cation exchange capacity (0.727). In contrast, four new weed species (Glyceria maxima, Leersia oryzoides,Scoparia dulcis and Anthoxanthum oculatum)were found due to the ammonium glufosinate application, in the different tillage systems.

The recovery of degraded pasture areas is based on the efficient use of forage grass in order to minimize weed interference. The objective of this study was to evaluate the effect of sowing densities in the population variation of weeds under the condition of reformed cultivated pasture of Urochloa brizantha cv. Marandu. The experiment was arranged in a randomized block design with four replications and treatments consisting of five sowing densities (0, 25, 50, 75 and 100) expressed as the percentage of the recommendation to use Marandu grass (15 kg ha-1) based on cultural value (60% purity and 60% germination). The seedling emerged on January 28, 2020. Weed identification and quantification was carried out from 7 to 49 days after emergence (DAE). The weed dry mass was obtained at 49 DAE and the plots were evaluated for the structural and productive characteristics of the forage. With the weed dry matter data, the relative importance was determined by the importance value index. Results were subjected to analysis of variance, and when significant, regression analysis was performed. There was a gradual decrease in the total number of individuals m-2 in the weed community according to the increase in sowing density, reaching a 55% reduction in sowing density of 75% at 42 DAE. Competition between species in the initial period of coexistence contributes to the low production of dry matter of Marandu grass sown at 25% of the recommendation for use. [ABSTRACT FROM AUTHOR]

ABSTRACT Invasive species influence the structure and functioning of ecosystems, as they affect native species, significantly decreasing their diversity. Aquatic ecosystems harbor a great biodiversity, and invasive macrophytes significantly affect the native plant communities, causing a cascade effect on other trophic levels. Among invasive macrophytes, Urochloa arrecta is cause for concern in the Neotropics and is found in several regions of Brazil, specially in the southeastern and southern regions. So far the species had been recorded only in the northern state of Amazonas. We report the first record of the species in the state of Pará, in the eastern Brazilian Amazon. We emphasize that identifying sites where this species is invasive is the best strategy to prevent its spread, aiming at the protection and conservation of Amazonian freshwater ecosystems.

RESUMO In this study a floristic survey of species of Poaceae from the restingas and dunes vegetation of Ilha do Maranhão, located in the north of Maranhão State, was performed. Collections in the study areas and analysis of material from Herbarium MAR and SLUI was carried out. Thirty species were found, the genus Paspalum L. was the richest genus, whit four species. An identification key to the founded species, descriptions and illustrations are provided.

The text aims to analyze the territorialization of the capital in Alagoa's agrarian space through the expansion of the wood-paper-cellulose complex. During a long period the monoculture of sugar cane occupied the best lands of the State, however within the last few years in the face of the sugar-ethanol sector crisis, extensive hectares of land, once designed to grasses, have been set as ide space to Eucalyptus monoculture. The phenomenon is inserted as part of the globalized accumulation of capitals context, in which capitalist stake possession of lands between the tropics for the monoculture of commercial trees, combining the trade of commodities, and to the financial capital. It is assumed that the extraordinary soil and climatic conditions found in Alagoas and the support offered by the State act as an incentive to the partial replacement the sugar cane for eucalyptus. The underlyingcontradictionsregardingthephenomenonfollowingtheexampleoftheState'sfoodsover eigntyweakeningandofenvironmentalimpacts, also are objects in the present reflection. [ABSTRACT FROM AUTHOR]

Abstract The Cerrado (Brazilian Savanna) biome suffers intense degradation due to several anthropic activities and its recovery is extremely important for the restoration of environmental quality. Therefore, the present study tested the survival and growth of seedlings of the grass Schizachyrium tenerum produced by the division of clumps. The experiment was carried out in a greenhouse using Reddish Oxisol, dystrophic of “cerrado sensu stricto” and Litholic Neosol dystrophic of quartzitic rupestrian grassland with and without the addition of limestone and NPK. Survival of S. tenerum was also compared between being grown in a greenhouse and directly in the field in full sun. Seedlings of S. tenerum had greater survival, total growth, number of tillers and accumulation of biomass when cultivated in Reddish Oxisol and Reddish Oxisol with limestone added than in the other treatments. Seedling survival was three times greater when grown in a greenhouse than in full sun.

ABSTRACT: Experiments were run in a greenhouse where samples of Eragrostis pilosa and Eragrostis plana, species that infest rice crops, were subjected to three soil moisture conditions (50% of soil water retention capacity (WRC), 100% of WRC, 10 cm water depth), simulating three different environments (upland, lowland and irrigated rice farm, respectively), with the aim of studying how these conditions affect the morphology and vegetative cycle of these plants, by means of development and growth assessments. Results show that each species responds differently when subjected to varying amounts of water in the soil. Soaking the soil with 10 cm of water was the treatment that most negatively influenced the development of E. plana plants, reducing the formation of panicles per plant, as well as the aerial part dry mass. The responses of E. pilosa plants to the waterlogged environment manifested as reductions in tillering parameters, number of panicles per plant, root and aerial part dry mass, changes in flag leaf formation, and vegetative cycle increases, which allows inferring that these plants are more sensitive to hypotoxic environments. Thus, the water depth treatment is possibly what caused negative effects on the development of the study plants, which indicates that water management in irrigated rice farming is of uttermost importance for management of invasive plants.

This study consists of a floristic survey of the Bambusoideae (Poaceae) species that occur in the Serra do Brigadeiro State Park (PESB). The study area is inserted in the Atlantic Forest, considered as one of the centers of bamboo endemism. We carried out expeditions from August 2013 to July 2015 for the collection of botanical material and observation of the species in their natural environment. In addition, the collections of the herbaria BHCB, CESJ, HUEFS, ISC, K, MG, RB, SPF, VIC, and VIES were analyzed. Six genera and 27 species were recorded in the PESB. The most diverse genus is Chusquea with 16 species, followed by Merostachys and Aulonemia with four species each, and Colanthelia, Guadua, and Parodiolyra with one species each. Identification keys for genera and species, descriptions, and morphological comments are presented. PESB has the highest bamboo species richness recorded for the conservation units of Minas Gerais. [ABSTRACT FROM AUTHOR]

We evaluated pollen production per anther, per flower, and per spikelet of the grassland species Bromus catharticus and the forest taxon Guadua trinii (Poaceae), which have divergent pollination syndrome. We collected ten anthers of each taxon to determine differences in pollen production based on pollination system. Anthers were macerated and pollen grains were counted in a Neubauer chamber. Pollen morphology was observed using optical and scanning electron microscopy to establish relationships between pollen grain production and morphology. The anemophilous species Bromus catharticus (2,556,000 pollen grains/spikelet) has twice the pollen production per anther and per spikelet compared to Guadua trinii (1,716,000 pollen grains/spikelet), a species that requires biotic assistance for pollination. Pollen grain size is inversely proportional to production. Microechinate ornamentation, which is not expected to occur in anemophilous species, was observed on pollen of both taxa. Our results indicate that the frequency of forest Poaceae in the quaternary records may be underestimated while frequency of grassland taxa may be overestimated, leading to misrepresentation of the respective flora in this period.

ABSTRACT This study aimed to isolate and identify endophytic fungi from the forage grass P. maximum and evaluate their ability to inhibit the growth of plant pathogenic fungi. One sample from P. purpureum grass was also included. Surface disinfected stem fragments were used for endophytic fungal isolation. One hundred and twenty-six endophytic fungi were isolated, of which 118 were from P. maximum and eight from P. purpureum. Morphological characteristics and internal transcribed spacer (ITS) and 18S (NS) sequence comparisons identified most isolated endophytic fungi as belonging to the phylum Ascomycota, with Sarocladium being the dominant genus. The isolates were subjected to in vitro antagonism tests against pathogenic fungi, and 31 endophytic fungi inhibited the growth of Bipolaris maydis, Penicillium expansum, and Sclerotinia minor. The results expand our knowledge of the diversity of endophytes associated with tropical grasses and suggest that they may represent new sources of antifungal metabolites for biocontrol and biotechnological purposes.

This study aimed to evaluate the control and susceptibility of signalgrass and ruzigrass in initial growth under different rates of glyphosate and fluazifop-p-butil. The treatments were distributed in a 2 × 6 factorial design, with five repetitions, being two grasses: Brachiaria decumbens cv. Basilisk (signalgrass) and B. ruziziensis (ruzigrass) with six doses of herbicides: 0.00; 0.25; 0.50; 1.00; 1.5 and 2.00 times the commercial dose recommended by manufacturers. At 7, 15, 21, and 30 days after herbicide application (DAA) were evaluated the intoxication in signalgrass and ruzigrass, visually. The glyphosate toxicity was of 100% in both plants, signalgrass and ruzigrass, even at the lowest dose (90 g ha-1), so it can control effectively these species in early growth stage. It was observed that the plants exposed to fluazifop-p-butil showed regrowth only in the doses to 100 g ha-1 and 50 g ha-1 for signalgrass and ruzigrass, respectively. These results confirm the effectiveness of this herbicide molecule in the control of these two species from doses of 200 g ha-1 and 100 g ha-1 for signal grass and ruzigrass, respectively. [ABSTRACT FROM AUTHOR]

The objective of the study was to evaluate periods of sealing in Brachiaria brizantha cv. pastures. Xaraés and its implications on morphological, structural, Bromatological and production of pastures. The experiment was conducted in randomized blocks, with four periods of deferment (30, 60, 90 and 120 days), each with three replications, totaling 12 experimental units. The number of live leaves (NFV), presented quadratic behavior (P0.05) with the increase of the deferral period. The height of the sward obtained increasing linear result (P0.05). The total dry matter adjusted to the increasing linear model (P0.05) for the NDF. The 60-day period of deferral is the most recommended for Brachiaria brizantha cv. Xaraés.

Additional procedures in the study of grasses are needed to improve animal performance in tropical regions of Brazil, as the increase in voluntary forage intake is related to the volume of the cell wall in leaf blades, referring to the vascular tissue, sclerenchyma, parenchyma bundle sheath cells, the C4 grasses which have become well developed and can influence the accessibility of rumen microorganisms. Added to this fact changes in nutritive value and sward structure, which vary throughout the seasons and can be correlated to the proportion and distribution of these tissues. This tissue differs in the plant by several factors, one of them is the presence or absence of secondary cell wall, another important factor is the arrangement that exists between them and that can generate barriers to the ruminal microorganisms, limiting digestion. So it is very important to know the anatomy of the forage, not only with the aim of adapting management strategies, physical and chemical treatments, selection and breeding of forage, but also explain the responses obtained with the animal performance, and the latter perhaps the main goal of understanding these barriers through the study of leaf anatomy. This review aims to expose some differences between C3 and C4 plants cycle, with main emphasis on anatomical characteristics evaluated by light and electron microscopy, as well as demonstrating the importance of the tissues that form the leaf blades and their specific functions.

With 94 species, Poaceae is one of the largest botanical families of the Upper Paraná River Floodplain (PIAP) and its environs, located between 22o38’–22o57’S and 53o5’–53o36’W, and covering areas of the Brazilian states of Mato Grosso do Sul and Paraná. Seasonally flooded, PIAP is part of the The Environmental Protection Area of the Islands and floodplains of the Paraná River (APA-IVRP) and State Park of the Ivinhema River Floodplain (PEVRI). Aiming to improve the botanical and ecological knowledge of the area and therefore contribute to its conservation, we studied the distribution pattern of the grasses of PIAP and its environs. For the grasses of PIAP we considered: phytophysiognomy, light exposure, photosynthetic pathway, water condition of the substrate where they preferably occur, classification of the morphovegetation, and the absolute and relative frequencies. The results show that the species are distributed according to the geomorphological configuration of the PIAP, which are presented here in two schematic profiles. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the behavioral parameters and strategies of displacement and feeding of cull cows grazing millet or sudan grass. The treatments consisted of: pearl millet (Pennisetum americanum (L.) Leeke) or sudan grass (Sorghum bicolor cv. Sudanense). Both treatments were submitted to continuous grazing of cull cows over 63 experimental days subdivided into three periods. Using 20 Charolais x Nellore cull cows, at the average age of 8 years and average weight of 445 kg. The animals were divided into 10 paddocks, five paddocks used for each treatment comprising two cows. The behavioral assessments were carried out for 24 hours straight. The experimental design was completely randomized with two treatments and three periods. The grazing time of cows showed interaction (P = 0.0035) between treatment and period, and the shortest time for the activity in the first period on pearl millet (504 minutes) compared to the second period of that same treatment (587 minutes) and the third period on sudan grass pastures (535 minutes). The times of rumination and idling were similar between treatments; however, the idling time decreased and rumination increased with time periods. The forage species did not affect the variables related to the strategies of displacement and feeding. With the advancement of cycle pastures the number of steps per minute, stations per minute and per day decreased while the bite rate and the number of bites per day increased. The behavioral parameters of cull cows grazing sudan grass or millet are similar; however, the advancement of the vegetative cycle of these species provides changes in the behavioral pattern of the animals.

O objetivo deste trabalho foi relacionar as características da anatomia foliar de Brachiaria decumbens (capim-braquiária) e Brachiaria plantaginea (capim-marmelada), em três estádios de desenvolvimento da planta, com a sensibilidade a herbicidas. A semeadura foi feita em vasos plásticos, contendo solo, mantidos em casa de vegetação. Foi amostrada a porção mediana do limbo da terceira folha expandida, a partir da base do colmo, compreendendo três estádios de desenvolvimento da planta: estádio 1 (com 4-6 folhas), estádio 2 (com 3-4 perfilhos) e estádio 3 (plantas adultas no início do florescimento). Foram quantificados os seguintes descritores anatômicos das regiões da quilha (nervura central) e da asa (porção entre a nervura central e a margem do limbo): área da secção transversal; porcentagens de epiderme das faces adaxial e abaxial, esclerênquima, bainha do feixe vascular, feixe vascular e parênquima; espessura da folha; distância entre os feixes vasculares; comprimento do estômato; e número de estômatos e de tricomas (curtos e longos). Os valores obtidos foram submetidos aos testes estatísticos multivariados de Análise de Agrupamento e Análise dos Componentes Principais. Os descritores avaliados permitiram diferenciar o estádio 3 de desenvolvimento da planta em relação aos demais, o qual pode ser considerado o menos sensível à ação dos herbicidas aplicados em pós-emergência.The aim of this study was to relate the leaf anatomical characteristics of Brachiaria decumbens ('Surinam grass') and Brachiaria plantaginea ('Alexandergrass') to herbicide sensitivity, at three developmental stages. The plants were sown in plastic pots filled with agricultural soil and kept in a greenhouse. The blade median portion of the third- expanded leaf, counted from the stem basis, was sampled, considering three developmental phases: stage 1 (plants presenting 4-6 leaves), stage 2 (plants presenting 3-4 tillers) and, stage 3 (adult plants in the beginning of flowering). The following leaf anatomy descriptors were quantified in the region of the keel (midrib) and wing (a portion between the midrib and the blade margin): transversal section area; percentages of epidermal cells in the adaxial and abaxial surfaces, sclerenchyma, vascular bundle sheath, vascular bundle, and parenchyma; leaf thickness; distance between vascular bundles; stomatal length; number of stomata and trichome (short and long). The values obtained were analyzed using multivariate statistical tests (Cluster Analysis and Principal Component Analysis). The leaf quantitative anatomical descriptors allowed differentiating stage 3 from the other stages as the least sensitive to the action of post-emergence herbicides.

Este estudo avaliou o impacto da presença da gramínea exótica (Brachiaria decumbens) na herbivoria e no desenvolvimento de plântulas de espécies nativas (Hymenaea stigonocarpa e Dipteryx alata) de Cerrado. Para avaliar o impacto da presença da gramínea, 10 blocos em pastagem (antiga área de Cerrado) na Embrapa Gado de Corte (Campo Grande-MS) foram demarcados em janeiro de 2009. As gramíneas foram mantidas intactas em metade dos blocos e, na outra metade, foram removidas. Em cada tratamento, foram avaliados a herbivoria, a altura e o diâmetro na altura do solo (DAS) de 25 plântulas de cada espécie ao longo do ano. O conteúdo de carbono, nitrogênio e água das folhas também foi quantificado. Plântulas de Hymenaea stigonocarpa nos tratamentos com gramínea tiveram maior taxa de crescimento em diâmetro que as plântulas no tratamento sem gramíneas. As plântulas de Dipteryx alata que estavam no tratamento sem gramíneas tiveram maiores taxas de crescimento em altura que as do tratamento com gramíneas. Houve diferença na taxa de herbivoria de D.alata entre os tratamentos. As plântulas das duas espécies que estavam no tratamento com gramínea mostraram maiores concentrações de carbono e menores de água. O conteúdo de nitrogênio foliar foi maior no tratamento com gramíneas que no sem gramíneas em D.alata; já o nitrogênio em H. stigonocarpa não variou entre os tratamentos. Esses resultados mostram que cada espécie nativa possui distintas respostas fisiológicas e suscetibilidade à herbivoria em ambientes sob competição de recursos com a gramínea exótica, B. decumbens.This study evaluated the impact of the presence of the exotic grass (Brachiaria decumbens) on the herbivory and development of seedlings of native species (Hymenaea stigonocarpa and Dipteryx alata) of the Cerrado. Thus, 10 pasture plots (former Cerrado) at the Embrapa Gado de Corte (Campo Grande-MS) were demarcated in January 2009. The grasses were kept intact in half of the plots and were removed in the other half. In each treatment, the herbivory, as well as height and diameter at ground level (DGL) of 25seedlings of each species were evaluated during one year. Carbon, nitrogen and water content of the leaves in each treatment were also quantified. Seedlings of Hymenaea stigonocarpa in plots without grasses had higher diameter growth rates than seedlings in plots with grasses. Dipteryx alata seedlings grown in plots without grasses had a higher height growth rate than seedlings grown in plots with grasses. There was a difference in the herbivory rate of D. alata between treatments. Seedlings of plots with grasses for the two species showed a higher concentration of carbon and lower amount of water. The leaf nitrogen content was higher in plots with grasses than without grasses in D. alata, while nitrogen in H. stigonocarpa did not vary between treatments. These results showed that each native species had distinct physiological responses and susceptibility to herbivory in environments under resource competition with the exotic grass B. decumbens.

El análisis de los fitolitos es una de las disciplinas paleobotánicas utilizadas para la reconstrucción de ecosistemas pasados ya que proporcionan un registro preciso de una parte de la vegetación, en áreas concretas y en un momento determinado. Teniendo en cuenta la importancia de estos análisis se estudió la composición y variabilidad fitolítica de los sedimentos loéssicos cuaternarios de la Formación Tezanos Pinto en el sudoeste de la provincia de Entre Ríos. Los datos de base obtenidos permitieron caracterizar la paleocomunidad existente al momento de depositación de los sedimentos loéssicos. Las formas encontradas corresponden tanto a microfitolitos como a macrofitolitos, siendo del tipo bilobados y polilobados (asignables a gramíneas de la subfamilia Panicoideae), tipo saddle (subfamilia Chloridoideae) y tipo cónico o rondel (subfamilia Pooideae). También fueron hallados fitolitos provenientes de pelos, aguijones y ganchos, de células buliformes y de células largas (todos tipos celulares de origen epidérmico de gramíneas sin capacidad diagnóstica para diferenciar subfamilias), y otros producidos por taxones no graminoides (esféricos equinados) provenientes de la familia Arecaceae.Phytolith analysis is one of the paleobotanic disciplines used for the reconstruction of past ecosystems, because they provide a precise record of part of the vegetation for a specific time and place. In this context, the composition and variability of phytoliths in Quaternary loessic sediments from the Tezanos Pinto Formation in southwestern Entre Ríos province was studied. The data obtained allowed characterizing the paleocommunity that existed at the time when the loessic sediments were deposited. The found forms correspond to microphytoliths and to macrophytoliths, being of the bilobate and polylobate type (described for Poaceae subfamily Panicoideae), saddle type (subfamily Chloridoideae) and conical or rondel type (subfamily Pooideae). Also they were found phytoliths originated from hooks, prickles and macrohairs, from bulliforms cells and of long cells (all cellular types of epidermal origin of poaceae without diagnostic aptitude to differentiate subfamilies), and others produced for taxons non-grasses (echinate sphere) originated from the Arecaceae family.

In the early 1970's research was initiated by the cooperative USDA-ARS and University of Nebraska grass breeding program to develop perennial grasses adapted to the mid-continental USA with improved forage quality. The initial breeding and animal evaluation work focused on switchgrass (Panicum virgatum) but has since expanded to several other warm-and cool-season perennial grasses. The in vitro dry matter digestibility (IVDMD) test was selected as the measure of forage quality that was used in the breeding work because of its previous successful application on improving bermudagrass (Cynodon dactylon). In all of the grass species that we have studied to date, there is genetic variability for IVDMD and forage yield. IVDMD is a heritable trait with narrow sense heritability's ranging from 0.2 to 0.4 which are similar to heritability's for forage yield. If significant improvements or difference in IVDMD (> 1%) can be detected in small plot trials (r=6), differences in cattle gains among experimental strains or cultivars can be demonstrated in grazing trials. Averaged over both cool- and warm-season grasses, a 1% increase in in vitro dry matter digestibility (IVDMD) generally leads to a 3.2% increase in average daily gains of beef cattle. Because increased IVDMD generally does not result in a decrease in forage yield, this results in a net increase in animal production per hectare of land.No início dos anos 1970 foi iniciado um projeto cooperativo entre o Agricultural Research Service, do USDA, e a Universidade de Nebraska, para programa de melhoramento genético visando o desenvolvimento de gramíneas perenes com melhor qualidade de forragem e adaptadas ao centro continental dos Estados Unidos. Os estudos iniciais centraram-se em switchgrass (Panicum virgatum), mas depois foram extendidos a outras gramíneas perenes de estação fria e quente. A digestibilidade in vitro da matéria orgânica (DIVMO) foi selecionada como medida da qualidade, uma vez que já havia sido aplicada com sucesso no melhoramento de capim bermuda (Cynodon dactylon). Em todas as espécies de gramíneas que estudamos até o presente, foi encontrada variabilidade genética para DIVMO e produção de massa seca. Se melhorias na DIVMO maiores do que 1% puderem ser detectadas em estudos com parcelas pequenas (r = 6), pode se obter ganho diferenciado de peso de animais em função de ecotipos ou cultivares. Fazendo-se uma média entre gramíneas de estação quente e fria, aumento de 1% na DIVMO geralmente induz ganhos de peso de 3,2%. Como o aumento da DIVMO não causa decréscimo na produção de forragem, tem-se aumentos no ganho líquido de produção animal por hectare. Ganhos de peso de 3,2%. Como o aumento da DIVMO não causa decréscimo na produção de forragem, tem-se aumentos no ganho líquido de produção animal por hectare. Nas Planícies Centrais e Meio-Oeste Americano, cultivares com incremento de DIVMO podem aumentar o lucro líquido de 30 a 50 dólares por hectare.

Neste estudo, foram realizados dois ensaios com os objetivos de avaliar o fracionamento dos carboidratos de alimentos volumosos e estimar a digestibilidade desses nutrientes em dois ensaios de digestão com eqüinos. No ensaio 1, foram utilizados cinco eqüinos em delineamento de blocos casualizados, com sete tratamentos - fenos de alfafa (Medicago sativa); amendoim forrageiro (Arachis pintoi); desmódio (Desmodium ovalifolium); guandu (Cajanus cajan); macrotiloma (Macrotyloma axillare); estilosantes (Stylosanthes guianensis); ou coastcross (Cynodon dactylon) - avaliados pela técnica de sacos de náilon móveis. No ensaio 2, foram utilizados quatro eqüinos em delineamento quadrado latino 4 × 4, alimentados com feno de coastcross em quatro tipos de moagem com o objetivo de avaliar se a redução do tamanho de partícula interfere na digestibilidade dos carboidratos. Os resultados comprovaram que os eqüinos possuem alta eficiência na digestão dos carboidratos não-fibrosos e de suas frações hidrolisáveis e rapidamente fermentáveis. Os fenos de amendoim forrageiro, estilosantess e macrotiloma apresentaram elevada digestibilidade dos carboidratos fibrosos e não-fibrosos, enquanto a digestibilidade de todos os nutrientes do amendoim forrageiro foi superior a 70%, o que indica potencial para uso desta leguminosa em dietas para eqüinos. O processamento do feno de coastcross não influenciou a digestibilidade das frações dos carboidratos fibrosos e não-fibrosos. A análise dos carboidratos fibrosos e não-fibrosos é um bom indicativo do valor nutricional dos alimentos e pode ser incluída na avaliação da qualidade de alimentos para eqüinos.This work was carried out to evaluate the fractions of carbohydrates and estimate the apparent digestibility of these nutrients in two digestion assays with horses. In assay 1, five horses were allotted to a complete randomized blocks design and treatments were seven forages hays, alfalfa (Medicago sativa), peanut forage (Arachis pintoi), desmodio (Desmodium ovalifolium), pigeon pea (Cajanus cajan), lime-yellow pea (Macrotyloma axillare), stylo (Stylosanthes guianensis) e coastcross (Cynodon dactylon), evaluated with the mobile nylon bag technique. In assay 2, four horses were allotted to a 4 × 4 Latin Square design and fed with coastcross hay with four different processed forms with the objective of evaluating whether a reduction of the particle size affected the carbohydrate digestibility. Results showed that horses had high digestion of non-fibrous carbohydrate and hydrolysable carbohydrate and rapidly fermentable carbohydrate fractions of forages. Among the forages analyzed, peanut forage, stylo and lime-yellow pea, presented high nutrient digestibility, and the peanut forage nutrients presented digestibility above 70%, demonstrating potential to be used in diets for horses. The coastcross hay processing in different grinding degrees does not affect the fibrous and non-fibrous carbohydrate fractions digestibility. Analysis of fibrous and non-fibrous carbohydrate fractions is a good indicative of nutritional value of feeds, and could be included in the evaluation of the quality of diets for horses.

O aperfeiçoamento nos últimos anos das lentes de aumento e dos microscópios, bem como o desenvolvimento de técnicas de preparação de amostras, disponibilizou excelentes ferramentas para pesquisas nas diversas áreas da ciência. As avaliações ao microscópio, eletrônico ou óptico, de alimentos utilizados para ruminantes, têm auxiliado na compreensão da relação causa/efeito no desempenho animal. Destacam-se os avanços obtidos no conhecimento do modo de ação dos microrganismos do rúmen nos substratos, principalmente das bactérias partículo-associadas. Avanços também foram obtidos no entendimento dos fatores que afetam a degradabilidade da matéria seca de forrageiras, especialmente das espécies C3, mas estes avanços também contribuem para o conhecimento das C4. Os resultados destes estudos permitiram o estabelecimento de várias linhas de pesquisa, possibilitando discriminar-se nas fases iniciais de seleção de gramíneas e leguminosas, aquelas que apresentam maior potencial qualitativo. Destacam-se também os estudos que estão sendo realizados para elevação da degradabilidade do colmo de milho e do caule da alfafa, bem como, aqueles para identificar-se como o tratamento de subprodutos agrícolas pode elevar sua qualidade, e se verificar o efeito de inoculantes, tais como enzimas exógenas, na taxa de degradação da matéria seca. Além de se verificar o efeito do tanino, especialmente em leguminosas, na digestibilidade, o que pode no futuro possibilitar a utilização de aditivos que minimizem ou anulem seus efeitos deletérios no consumo de forragem. Com relação aos grãos de cereais, pode-se verificar a influência do genótipo na degradação. Os resultados obtidos até então, fornecem a base para a manipulação genética de alimentos utilizados por ruminantes, o que provavelmente será objeto de pesquisa nas próximas décadas.The perfecting in the last years of augmentation lenses and that of the microscopes, as well as the development of samples preparation techniques, provided excellent tools in the several science areas. The evaluations at the microscope, electron or optical, of edible products utilized for ruminants, has helped in the cause/effect relationship understanding in animal performance. Of paramount importance are the advances obtained in the action mode of rumen microorganisms in the substrates knowledge, mainly of the particle-associated bacteria. Advances were also achieved in the knowledge of factors that affect the forage dry matter degradability, especially of the C3 species, but these advances also contribute to the knowledge of the C4. These studies results allowed the establishment of several research lines, creating the possibility of discrimination in the early stages of grasses and legumes selection, those which present the greatest qualitative potential. There is especial merit also in the studies to increase the corn and alfalfa stalk degradability, as well as those to identify how the agricultural byproducts treatment can increase its quality, and to verify the effect of inoculants, such as exogenous enzymes, in the dry matter degradability rate. Besides the verification of the tannin effect, especially in legumes, into the digestibility, which may in the future to foster the utilization of additives that can minimize or prevent their harmful effects on forage consumption. With relation to cereal grains, it may be verified the genotype influence on degradability. The results achieved up to now, give the base for the genetic manipulation of feed stuff utilized by ruminants, which probably will be object of research in the next decades.

En épocas de lluvia (mayo de 2006) y de sequía (agosto de 2006), en tres sitios de la zona de ladera de los municipios de Bolívar, Sevilla y El Dovio, se evaluó mediante metodologías participativas el proceso de adaptación de tecnologías forrajeras. Se aplicaron evaluaciones abiertas, absolutas y de orden de preferencia, esta última se procesó con la metodología de regresión logística. Se utilizó un diseño de bloques al azar con tres repeticiones para las leguminosas y gramíneas respectivamente. Los resultados de las evaluaciones de los productores coincidieron con las de los técnicos. El primer lugar entre leguminosas herbáceas, leguminosas arbustivas y gramíneas lo ocuparon C. brasiliensis, L. leucocephala y B. brizantha cv. Toledo, respectivamente.During the rainy season (May of 2006) like in dry season (August of 2006), in three sites located on hillsides zones from Bolivar, El Dovio and Sevilla municipalities of Valle del Cauca Department, Colombia, the adaptation process for forage technologies using participative methodologies was evaluated. Open evaluations, absolute evaluations and of preference order evaluation were applied; the last one was statistically analyzed with the methodology of logistical regression. A randomized block design was used, with three replicates for legumes and grasses, respectively. The results of the evaluations by the farmers coincided with that the carried out by technicians. The results of the investigation ranked in the first place the herbaceous legumes, shrub legumes, and grasses, C. brasiliensis, L. leucocephala and hybrid Brachiaria cultivar Toledo, respectively.

The Reserva Biológica do Alto da Serra de Paranapiacaba (RBASP) is located in the state of São Paulo, in an area of Atlantic Forest, one of the most biodiverse and threatened biomes of the world. This study aimed to carry out a floristic survey of the grasses (Poaceae) from RBASP through field sampling and by analyzing the collections of herbarium SP, which houses an important collection of plants from the RBASP. 47 genera and 88 species of grasses were recorded. Seven of these species represent new records, fifteen are exotic, five are cultivated, and six are threatened in the state of São Paulo and/or in Brazil. This study includes comments about the global and local distribution, conservation statuses, critical analysis of the previously published checklists, identification keys, as well as a list of voucher specimens from RBASP and images of some selected taxa. [ABSTRACT FROM AUTHOR]

Objetivou-se neste trabalho avaliar a interação competitiva de Brachiaria brizantha e B. plantaginea sob doses reduzidas de fluazifop-p-butil, aplicadas em diferentes épocas. O delineamento experimental adotado foi o de blocos casualizados, com quatro repetições, seguindo o arranjo fatorial 6x3, com seis doses de fluazifop-p-butil (7,5; 12,5; 18,75; 31,25; 43,75 e 62,5 g ha-1), aplicadas em três épocas (14, 24 e 34 dias após a emergência das plantas - DAE), mais uma testemunha sem herbicida. A maior dose utilizada correspondeu a 33% da dose recomendada para a cultura da soja (187,5 g ha-1). A avaliação dos tratamentos foi realizada aos 53 DAE das espécies. As plantas foram desmembradas em folhas e colmos, determinando-se a biomassa seca das partes. Foram também avaliados a área foliar, o número e o comprimento dos colmos. B. plantaginea foi mais suscetível ao fluazifop-p-butil do que B. brizantha. A dose de 25 g ha-1 do herbicida, aplicada aos 14 DAE, permitiu máximo acúmulo de biomassa seca de B. brizantha e controlou satisfatoriamente B. plantaginea. Aplicando-se nessa mesma época a dose de 62,5 g ha-1 de fluazifop-p-butil, as duas espécies foram controladas. Quanto ao efeito de épocas de aplicação, quando utilizadas doses reduzidas, que não visam o controle pleno das espécies, plantas mais jovens de B. brizantha e B. plantaginea apresentaram melhor capacidade de recuperação.The objective of this work was to evaluate the competitive interaction between Brachiaria brizantha and B. plantaginea under reduced rates of fluazifop-p-butyl and different application timings. The experimental design was a randomized complete block, with four replications, arranged in a 6 x 3 factorial, consisting of six doses of fluazifop-p-butyl (7,5; 12,5; 18,75; 31,25; 43,75 and 62,5 g ha-1), applied in three times (14, 24 and 34 days after plant emergence - DAE) and a control without herbicide. The highest dose applied corresponded to 33% of the recommended dose for soybean (187,5 g ha-1). The evaluation of the treatments was accomplished 53 DAE. The plants were grouped into leaves and stems, and their dry biomass obtained. Leaf area, stem number and stem length of both species were determined. B. plantaginea was more susceptible to fluazifop-p-butyl than B. brizantha. It was observed that 25 g ha-1 of fluazifop-p-butyl, applied at 14 DAE allowed maximum B. brizantha dry biomass accumulation and satisfactory control of B. plantaginea. In this application timing the dose of 62.5 g ha-1 controlled both species. Regarding application timing, when treated with reduced doses not intended to achieve full species control, young plants of B. brizantha and B. Plantaginea presented better recovery ability.

As características da digestão das forragens podem ser mais bem compreendidas quando complementadas com estudos de anatomia dos tecidos de plantas forrageiras. Com o objetivo de agregar novas informações ao tema, determinou-se a área dos diversos tecidos presentes na folha e no colmo de Brachiaria brizantha e B. humidicola, em três diferentes níveis de inserção no perfilho. O experimento foi conduzido em casa de vegetação, com plantas mantidas em vasos plásticos contendo areia esterilizada e recebendo solução nutritiva de macro e micronutrientes. Após 70 dias do corte de uniformização das parcelas (vasos), coletou-se o segmento do colmo e da folha (limbo e bainha) situado na porção mediana de cada um dos três diferentes níveis de inserção do perfilho estudado. As amostras foram emblocadas em GMA, seccionadas em micrótomo e o laminário fotomicrografado. As fotografias foram digitalizadas e as áreas de tecidos, mensuradas com software Image Tool. Observou-se que o limbo das folhas basilares apresentou menor área de tecido vascular lignificado. Maior área de tecido parenquimático foi observada na bainha e no colmo da B. brizantha. Em relação à B. humidicola, a B. brizantha apresentou maior área de tecido vascular lignificado no limbo, bainha e colmo. Maior distância entre os feixes vasculares foi observada no limbo e na bainha, sendo o número de feixes maior no limbo e no colmo.The forage digestion characteristics can better be understood when associated with studies of tissue anatomy of forage species. Aiming at new focus to this issue, the area of several tissues present in leaves and stems of B. brizantha and B. humidicola, were determined at three different regions of the plant. The assay was carried out at greenhouse, with plants growing in pots with sterilized sand, receiving nutritive solution of macro and micronutrients. After 70 days of growing period, the segment of leaf and stem localized in the center of each of three different insertion planes was collected. The samples were fixed in FAA, embedded in GMA, sectioned in microtome, stained and photographed. The pictures were digitalized and the areas measured with Image Tool software. It was observed that the limbo at bottom plane presents lower area of lignified vascular tissue. On the other hand, at the sheath and stem of B. brizantha, a larger area of parenchymal tissue is found. Compared to B. humidicola, B. brizantha showed greater area of lignified vascular tissue at the limbo, sheath and stem, while the greatest distance among bundle sheath is found at the limbo and sheath, where the number of bundle sheath was higher at the limbo and stem.

A utilização de cereais de inverno no sistema de duplo propósito permite fornecer aos animais forragem verde no período crítico de carência alimentar, além de aumentar a estabilidade da receita da produção pela melhoria na qualidade e produtividade dos grãos dos cereais de inverno. O experimento foi conduzido no período de abril de 1994 a setembro de 1996 em Guarapuava, Paraná, a fim de avaliar o potencial de utilização para forragem e grãos de aveia branca (Avena sativa L.), trigo (Triticum aestivum), triticale (X. Triticosecale Witt.), aveia preta (Avena strigosa Schreb), centeio (Secale cereale L.) e cevada (Hordeum vulgare L.), visando sua utilização em condições de duplo propósito. Utilizou-se o delineamento experimental de blocos ao acaso, com tratamentos distribuídos em parcelas subdivididas, em três repetições. Nas parcelas foram estudados os sistemas de produção (sem corte, um e dois cortes) e nas subparcelas, os genótipos. O sistema de dois cortes foi superior aos demais quanto ao rendimento de matéria seca, principalmente para a aveia. Para o rendimento de grãos, os sistemas sem corte e um corte foram superiores, apesar da maior produção dos genótipos de aveia sob dois cortes. Em todos os genótipos, houve melhoria do peso do hectolitro e redução da massa de mil sementes, quando se realizaram cortes. Sob condições de manejo adequadas, pode-se alcançar considerável produção de forragem, sem afetar a posterior produção de grãos para cereais de inverno.The winter cereals utilization in double purpose system allows to provide forage in critical food conditions periods and also to increase the income of production stablility by improving quality and produtivity of winter cereal grains. The experiment was conducted from April 1994 to September 1996, in Guarapuava, Paraná, to evaluate the potential for forage and grains of white oat (Avena sativa L.), wheat (Triticum aestivum), triticale (X. Triticosecale Witt.), black oat (Avena strigosa Schreb), rye (Secale cereale L.) and barley (Hordeum vulgare L.), seeking an use in conditions of double purpose. A randomized block experiment design, with treatments assigned to subdivided portions, in three replications, was used. In the plots the production systems (without cut, one and two cut) were studied and in the sub-plot, the genotypes. The two cut system was superior than the others concerning the dry matter, mainly the oat. For the grain yield, the systems without cut and one cut were superior, in spite of the greatest production of oat genotype under two cut. In all genotypes, the hectoliter weight increased and the mass of a thousand seeds decreased, when cuts were performed. Under apropriate handling conditions, considerable forage production can be reached, without affecting the posterior production of grains for winter cereals.

The objective of this study was to evaluate the effect of different water regimes on some aspects of root anatomy of three grasses: Echinochloa pyramidalis (canarana), Setaria anceps (setária) and Paspalum paniculatum (paspalo). The plants were cultivated in a greenhouse and submitted to three water regimes: daily watering; suspension of watering and suspension of watering followed by submersion of the root system. Segments of the middle part of the roots were taken and submitted to classical techniques in botany for slide making and tissue analysis. Anatomical differences were observed among the three grasses submitted to water regimes regarding the number of cell layers in the external cortex and thickening of lignin and suberin. The submerged roots of the three species presented an increasing tendency in the proportion of the area of the cortex destined for the aerenchyma besides thickening of the endodermis and the cells of the medullar parenchyma. The aerenchyma presence in the three water regimes suggested it is a characteristic of these species. The adaptations developed by these species contributed to the understanding of their occurrence in areas that are subject to drought periods and successive floods.Conduziu-se o presente trabalho objetivavando-se avaliar o efeito de diferentes regimes hídricos sobre alguns aspectos da anatomia da raiz das seguintes gramíneas: Echinochloa pyramidalis (canarana), Setaria anceps (setária) e Paspalum paniculatum (paspalo). As plantas foram cultivadas em casa-de-vegetação e submetidas a três regimes hídricos: regas diárias; suspensão da rega e suspensão da rega seguida de submersão do sistema radicular. Foram retirados segmentos da parte mediana das raízes, os quais foram submetidos a técnicas clássicas em botânica para confecção de lâminas e análise de tecidos. Foram observadas diferenças anatômicas nas três espécies de gramíneas submetidas aos três regimes hídricos com relação ao número de camadas de células do córtex externo e o espessamento de lignina e/ou suberina. As raízes em submersão nas três espécies apresentaram uma tendência de aumento na proporção da área do córtex destinada a aerênquimas, além de um espessamento tanto da endoderme como das células do parênquima medular. Pela presença de aerênquimas nas três espécies sujeitas aos três regimes hídricos, infere-se que esses são constitutivos. As adaptações desenvolvidas por essas espécies contribuíram na compreensão da ocorrência dessas em áreas que passam por períodos de seca e inundações sucessivas.

O objetivo deste estudo foi avaliar a composição e dinâmica da biomassa aérea após a queima de uma savana gramíneo-lenhosa no Pantanal. Foram coletados dados mensais de freqüência de espécies, biomassa aérea e cobertura do solo durante 11 meses em uma área com queima (CQ) e outra sem queima (SQ), ambas sem pastejo. A queima reduziu a freqüência das gramíneas predominantes e condicionou aumento no número de espécies dicotiledôneas e ciperáceas. A produção de biomassa aérea total foi inferior na área com queima, embora a tendência de incremento tenha sido semelhante nas duas áreas. A produção de biomassa morta foi muito afetada pela queima, cuja produção, 11 meses após, representou aproximadamente 25% da obtida na área sem queima. A cobertura do solo foi inferior na área com queima e somente no quarto mês assemelhou-se à área sem queima.The purpose of this work was to evaluate composition and aerial biomass dynamics after burning of a grassy-woody savanna in the Pantanal wetlands, Brazil. During 11 months, data on species frequency, aerial biomass and soil cover were collected in an area with burning (WB) and another free of burning (FB), both not grazed. Burning reduced the frequency of the most predominant grasses and increased the number of dicotyledons and cyperaceae species. The production of total aerial biomass was lower in the WB area, despite an increase tendency that was similar in both areas. Litter production was strongly affected by burnings. After 11 months its production was approximately 25% of the production exhibited by the FB area. Soil cover was also lower in the WB and only after four months it was similar to the FB area.

O experimento, conduzido na microrregião dos Cariris Velhos, do Estado da Paraíba, teve como objetivo observar a influência da precipitação e idade da planta ao primeiro corte, na produção de matéria seca e composição química do capim-buffel. Esta precipitação foi simulada pela aplicação de água pelo sistema de irrigação por aspersão tipo canhão. O delineamento experimental usado foi em blocos ao acaso, com seis repetições, e os tratamentos constaram da combinação de cinco lâminas totais de água e seis idades ao primeiro corte. A aplicação de água aumentou o rendimento de matéria seca em todas as idades ao primeiro corte, e o máximo rendimento estimado (5.191 kg ha-1) ocorreu com a aplicação de uma lâmina de água de 334 mm e corte aos 80 dias após a germinação. A quantidade de água aplicada não influenciou o teor de proteína bruta; entretanto, este decresceu linearmente com a idade da planta. O teor de fibra bruta aumentou com a quantidade de água aplicada. A idade da planta ao primeiro corte não exerceu influência na porcentagem de fibra bruta.The experiment was conducted at the micro region of Cariris Velhos, Paraíba State, Brazil, and its objective was to observe the influence of precipitation and age of the plant at the first cut on the production of dry matter and chemical composition of the buffel grass. This precipitation was simulated by water application through a gun sprinkler system irrigation. The experimental design used was a randomized block with six replications, and the treatments consisted of combining five water depths and six ages at the first cut. The water application increased the dry matter production in all plant ages at the first cut; the estimated maximum yield of 5,191 kg ha-1 occurred with a water depth of 334 mm, and the cut was done 80 days after germination. The amount of applied water did not influence the crude protein content; however, it decreased linearly with the age of the plant. The crude fiber content increased with the amount of water applied. The age of the plant at the first cut did not influence the percentage of crude fiber.

Foram feitas observações relativas ao florescimento de seis espécies de gramíneas forrageiras tropicais cultivadas sob condições de luminosidade reduzida. Os resultados indicam efeito negativo do sombreamento sobre a floração da maioria das espécies estudadas, sendo recomendados novos ensaios visando à quantificação das sementes produzidas e à avaliação da qualidade fisiológica dessas.The influence of reduced light on the flowering of six tropical grass forage was studied. The results showed that shading has affected negativelly the flowering of most species and new researchs are recommended to quantify the seed production and evaluate the physiological seed quality.

RESUMO - Com o objetivo de aumentar a disponibilidade de germoplasma para produção de forragem, 215 acessos do gênero Paspalum coletados em diferentes regiões do país foram introduzidos na Embrapa Pecuária Sudeste, situada na região central do Estado de São Paulo. Estes acessos foram avaliados e selecionados com base em suas produções, de primeiro ano, de matéria seca referentes ao desenvolvimento vegetativo durante o ano e nos períodos de alta e baixa precipitação pluvial no ano. Os acessos foram avaliados em três experimentos em delineamento experimental em blocos ao acaso, com duas repetições. A produção de matéria seca foi obtida e analisada em quatro cortes durante o ano (MSANO), os quais eram representativos do desenvolvimento dos períodos de primavera/verão (MSCHUVA) e outono/inverno (MSSECO). As análises individuais, por experimento, mostraram a presença de variabilidade entre os acessos para as características avaliadas. A análise conjunta para experimentos foi realizada pela metodologia de análise conjunta de experimentos em blocos ao acaso com tratamentos comuns (testemunhas - Brachiaria decumbens e Andropogon gayanus cv. Baetí). Em virtude de a variância obtida pela interação entre tratamentos comuns por experimentos ter sido significativa, a seleção dos acessos foi realizada dentro de cada um dos experimentos, escolhendo-se aqueles que apresentaram produção no mínimo igual à menor produção das testemunhas naquele experimento. Cinqüenta e oito acessos foram selecionados (27%), demonstrando a possibilidade de serem obtidas cultivares com produtividade de matéria seca igual ou superior à das cultivares utilizadas como testemunhas.ABSTRACT - With the objective to increase the germoplasm availability for forage production, 215 accessions of the genus Paspalum collected in different regions and introduced at the Embrapa Southeast - Cattle Research Center, located at the central region of the São Paulo state. These accessions were evaluated and selected based on their yields in the first year, of dry matter from the vegetative development throughout the year and during the period of high and low rain preciptation. The accesses were evaluated in three experiments using a randomized blocks desing with two replicates. Dry matter production was obtained and analyzed from four cuts during the year (DMYEAR), which were representative of the development during the spring/summer (DMRAINY) and autumn/winter (DMDRY) seasons. The individual analyses, per experiment, showed variability among the accessions for the evaluated characteristics. The analyses as a set for the experiments was analyzed by the methodology of total analyses of the experiments in a randomized blocks desing with a common treatments (controls - Brachiaria decumbens and Andropogon gayanus cv. Baetí). Due to the significant variance interaction among common treatments by experiments, the selection was done for each experiment by choosing the accesses that presented yields at least equivalent to the worst control. Fifty-eight accessions were selected (27%), which demonstrated the possibility of obtaining cultivars with dry matter yields equal or better than the controls.

Under controlled conditions, six forage grasses (Setaria anceps cv. 'Kazungula' and Brachiaria brizantha cv. 'Marandu'; and codified genotypes BB33, BB39; BBS 5 and BBS8), along with a control check (sugarcane cv. 'SP80-1842') were evaluated as to Mahanarva fimbriolata resistance. The following parameters have been evaluated: nymphal phase duration and mortality, sex ratio, pre-oviposition period, number of eggs per female, longevity, viability and embryonic period. The highest mortalities and longer nymphal periods occurred on BBS 8, cv. 'Marandu' and cv. 'Kazungula'. BBS5 also caused high nymph mortality, however with the shortest nymphal period. The lowest longevity and fecundity values were detected for BBS5 and BBS8, whereas the sugarcane control check revealed the highest one. As to embryonic phase viability, BBS 8 originated the highest values and BBS 5, the lowest ones. Among the tested plants, BBS 8 along with the cv. 'Marandu', proved to be the most resistant genetic material, both through antibiosis and/or nonpreference for feeding mechanism. [ABSTRACT FROM AUTHOR]

The present study aims to survey the species of Poaceae in fragments of Atlantic Forest in Pernambuco state. Samplings were conducted between 2005 and 2008, with increased efforts between February 2007 and May 2008. The identification of species followed the usual methods in taxonomy and distribution data were obtained in the literature and surveys on specific databases. As a result, were identified 54 species and classified into 31 genera. This work presents identification keys, comments on the distribution of species and the habitats on which each was found. [ABSTRACT FROM AUTHOR]

The use of glyphosate to chemical control of Cutgrass and Peruvian Watergrass with the use of non-selective herbicides has not been efficient. In this context, the investigation of chemical control of these species to glyphosate is very important, since there are not available commercially selective herbicides to control these species in post-emergence of irrigated rice. Therefore, the objective of this study was to evaluate the susceptibility of Cutgrass and Peruvian Watergrass to different formulations of glyphosate. Two factorial experiments were conducted in a greenhouse, in the first the A factor were two formulations of glyhposate (potassium and isopropylamine salt) and the B factor were nine doses of the herbicide (zero; 175; 350; 700; 1400; 2800; 5600; 11200; 22400g a.e. ha-1). In the second experiment, the A factor were two species (Leersia hexandra and Luziola peruviana), the B factor were three formulations of glyphosate (amoniun, potassium e isopropylamine salt) and the C factor were nine doses of herbicides (zero; 87,5; 175; 350; 700; 1400; 2800; 5600; 11200g a.e. ha-1). Based on the results obtained, it was observed that these species exhibit differential susceptibility to glyphosate. Moreover, Leersia hexandra was more sensitive when compared to Luziola peruviana. Glyphosate formulation infl uenced control efficiency, where Transorb Roundup R® and Roundup Ultra® provided the best control of the two species. [ABSTRACT FROM AUTHOR]

The influence of rotational grazing intervals on morphogenesis of five native grasses from Rio Grande do Sul state (RS) central region, grouped according to a functional typology, was evaluated during spring and summer seasons. Leaf appearance rate, leaf elongation rate and leaf senescence rate (LAR/LER/LSR) phyllochron, leaf lifespan and leaf elongation duration (LLP/LED) were evaluated on Axonopus affinis, Aristida laevis, Andropogon lateralis, Paspalum notatum and Paspalum plicatulum, under two rotational grazing intervals, defined by thermal time (°C), 375 and 750 degree-day, during 2010 spring and 2010/2011 summer. There was no significant difference between grazing intervals, but there was among species and between seasons. Paspalum notatum highlights significant adjustments to grazing. Axonopus affinis and P. notatum presented the largest LAR and smallest LLP, while A. lateralis presented morphogenic characteristics which contradict literature. Spring and summer was characterized as the growing and fl owering periods, respectively. Grazing showed infl uence on forage morphogenesis, however, the evaluated grazing intervals had no effect on species development and the seasonal infl uence define native grasses development. [ABSTRACT FROM AUTHOR]

Copyright of Agricultural Research in the Tropics / Pesquisa Agropecuária Tropical is the property of Pesquisa Agropecuaria Tropical and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ciência Animal Brasileira is the property of Universidade Federal de Goias, Escola de Veterinaria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Agro@mbiente On-line is the property of Revista Agro@mbiente On-line and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)