Rediscovery of presumably extinct species of Aristida in São Paulo State, Brazil / Redescoberta de espécies presumivelmente extintas de Aristida no estado de São Paulo, Brasil

Abstract Two species of Poaceae (Aristidoideae) Aristida ekmaniana Henrard and A. macrophylla Hack. considered "presumably extinct" in the Brazilian state of São Paulo were rediscovered during fieldwork. We hereby describe the location, ecosystem, and habitat type where the species were found. We suggest these grasses be removed from the list of extinct species and be placed in a category compatible with the current knowledge about their conservation status in the state of São Paulo.

Resumo Duas espécies de Poaceae (Aristidoideae), Aristida ekmaniana Henrard e A. macrophylla Hack., consideradas "presumivelmente extintas" no estado de São Paulo, Brasil, foram redescobertas durante trabalho em campo. Descrição, ilustração e observações ecológicas são apresentadas, incluindo locais de observação, ecossistemas e habitats. Sugerimos a revisão do status de conservação das espécies no estado de São Paulo.

Chromosomes of two Olyra l. species from Misiones, Argentina (Poaceae, Bambusoideae, Olyreae) / Cromosomas de dos especies de Olyra l. de Misiones, Argentina (Poaceae, Bambusoideae, Olyreae)

ABSTRACT The subfamily Bambusoideae comprises three monophyletic tribes, Arundinarieae, Bambuseae and Olyreae. Here we report the gametic number and the chromosomal meiotic behavior of two species belonging to the herbaceous tribe Olyreae, Olyra latifolia and Olyrahumilis. Accessions were collected in Misiones, at Northeastern Argentina. We report a new gametic number for O. humilis, n=18, and we confirmed n=11 for O. latifolia. Chromosomal features, like the basic and gametic chromosome number, are important in understanding the evolution of the Poaceae family, especially in delimiting clades and elucidate inter andintra-clades relationships, and therefore it is necessary to continue producing this type of data.

RESUMEN La subfamilia Bambusoideae comprende tres tribus monofiléticas, Arundinarieae, Bambuseae y Olyreae. Aquí reportamos el número gamético y el comportamiento meiótico de los cromosomas de dos especies pertenecientes a la tribu Olyreae de bambúes herbáceos, Olyra latifolia y Olyra humilis. Las introducciones se recolectaron en la provincia de Misiones, en el noreste argentino. Reportamos un nuevo número gamético para O. humilis, n=18, y confirmamos n=11 para O. latifolia. Los números cromosómicos básicos y gaméticos son importantes para comprender la evolución de la familia Poaceae, especialmente para delimitar sus clados y las relaciones existentes entre ellos, por lo que es necesario continuar produciendo este tipo de datos.

LEAF ANATOMY CHARACTERIZATION OF FOUR Apochloa SPECIES: A C3 GENUS RELATED TO EVOLUTION OF C4 PATHWAY IN GRASSES / Caracterización anatómica de hojas de cuatro especies de Apochloa: un género relacionado con la evolución de la vía C4 en gramíneas

ABSTRACT Leaf anatomy characteristics provide important evidences about the transition between C3 and C4 pathways. The C4 photosynthesis pathway allowed to reduce the C3 photorespiratory rate, concentrating CO2 around the Rubisco site and using structures and machinery already presented in C3 plants. In monocots, it is observed a high number of C4 lineages, most of them phylogenetically related to C3 groups. The genus Apochloa (C3), subtribe Arthropogoninae, is related to two C4 genera Coleataenia and Cyphonanthus. The aim of this study was to evaluate four Apochloa species in order to establish anatomical characteristics related to the evolution of C4 pathway in this group. By means of transverse sections fully expanded leaves of A. euprepes, A. lorea, A. molinioides, and A. poliophylla were collected and the characteristics of the mesophyll (M) and bundle sheath (BS) cells were determined. These species showed a rustic Kranz anatomy with enlarged and radial arranged BS cells, which have few organelles organized in a centrifugal position. Although the modifications of BS cells are probably related to the maintenance of plant water status, we also discuss the evolution for the establishment of C4 photosynthesis in the related C4 genera.

RESUMEN Las características de la anatomía de la hoja proporcionan evidencias importantes sobre la transición entre las vías C3 y C4. La fotosíntesis C4 surgió para reducir la tasa de fotorrespiración C3, concentrando el CO2 alrededor del sitio de la Rubisco y utilizando estructuras y maquinaria ya presentes en las plantas C3. En monocotiledóneas, se observa un alto número de linajes C4, la mayoría de ellas filogenéticamente relacionadas con grupos C3. El género C3 Apochloa, que pertenece a la subtribu Arthropogoninae, está relacionado con dos géneros C4 Coleataenia and Cyphonanthus. En este contexto, el objetivo fue evaluar cuatro especies de Apochloa para establecer las características anatómicas relacionadas con la evolución de la via C4 en este grupo. Se colectaron hojas completamente expandidas de A. euprepes, A. lorea, A. molinioides y A. poliophylla y se determinaron las características de las células del mesófilo (M) y del haz de la vaina (HV) a partir de secciones transversales de la hoja. Las especies presentaron una anatomía rústica de Kranz con células HV agrandadas y de distribución radial, con pocas organelas organizadas en posición centrífuga. Aunque las modificaciones de las células HV están probablemente relacionadas con el mantenimiento del estado hídrico de la planta, se puede inferir que facilitan el establecimiento de la fotosíntesis en los géneros C4 relacionados.

New records of the invasive macrophyte, Urochloa arrecta extend its range to eastern Brazilian Amazon altered freshwater ecosystems

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. (AU)

Spatialization of Tibraca limbativentris Stål in irrigated rice: a geostatistical approach / Espacialização de Tibraca limbativentris Stål em arroz irrigado: uma abordagem geoestatística

The objective was to identify the dispersion of Tibraca limbativentris (Hemiptera: Pentatomidae) in different phenological phases of irrigated rice. The research was carried out in an area of 20.12 ha, subdivided in four fields of 0.25 to 14.1 ha with the irrigated rice culture, grown under the technical recommendations of the culture. In each field, a sampling grid of 30 × 30 m was generated, with each sampling point corresponding to 1·m-2 (200 plants), sampling was through direct counting. The number of adults of T. limbativentris·m-2 was subjected to descriptive and geostatistical analyzes. Tibraca limbativentris presents border dispersion towards the center of the irrigated rice cultivation area. The highest population densities were estimated in the anthesis and elongation phase.(AU)

O objetivo foi identificar a dispersão de Tibraca limbativentris (Hemiptera: Pentatomidae) em diferentes fases fenológicas do arroz irrigado. A pesquisa foi realizada em uma área de 20,12 ha, subdividida em quatro lavouras de 0,25 a 14,1 ha com a cultura de arroz irrigado, cultivadas sob as recomendações técnicas da cultura. Em cada lavoura, foi gerado um grid de amostragem de 30 × 30 m sendo cada ponto amostral correspondente a 1·m-2 (200 plantas), a amostragem realizada foi através de contagem direta. O número de adultos de T. limbativentris·m-2 foi submetido a análises descritivas e geoestatística. Tibraca limbativentris apresenta dispersão das bordaduras para o centro da área de cultivo de arroz irrigado. As maiores densidades populacionais foram estimadas na fase de antese e elongação.(AU)

Phenology and dry mass production of Urochloa plantaginea and Urochloa platyphylla submitted to different water quantities in the soil

The genetic variability and genetic versatility of plants belonging to Poaceae provide morphophysiological responses that allow these individuals to adapt to environmental changes, especially in relation to soil moisture. Urochloa plantaginea and U. platyphylla are grasses typical of dry environment, also found as weeds in rice fields, where there are high amounts of water in the soil. The objective of this work is to analyze the development of these two species in different environments, subjecting them to three different amounts of water in the soil. Morphological parameters were analyzed in order to verify and quantify which suffered alteration with respect to water variation. Caryopsis of the two species were collected in a commercial irrigated rice crop. Seeds were sown in pots containing a substrate-sand system, and housed in a greenhouse, where during the experiment the control of different moisture contents (shallow water table, 100% of field capacity and 50% of field capacity) took place. Weekly evaluations were carried out according to the parameters analyzed. The following parameters were evaluated: duration of the vegetative and reproductive life cycle, number of the inflorescences per plant, number of branches per inflorescence, number of spikelets per branch, number of seeds per plant, and dry mass production. The U. plantaginea cycle had shorter duration under the shallow water table, while for U. platyphylla the shorter duration was under the condition 50% of field capacity. Both species produced higher dry mass of shoots under the condition of 100% of field capacity. The main responses observed for both species, due to the flooding, were the change of the cycle, reduced dry matter production, and reduced seed production.

Aristida asplundii (Poaceae: Aristidoideae) un nuevo registro para la flora peruana / Aristida asplundii (Poaceae: Aristidoideae) a new record for Peruvian flora

Reportamos por primera vez la presencia de Aristida asplundii Henrard (Poaceae, Aristidoideae) para Perú basada en colectas de la región Puno (sur del Perú). Incluimos una clave que permite diferenciar las especies de Aristida que habitan en Perú.

We report for the first time the presence of Aristida asplundii Henrard (Poaceae, Aristidoideae) for Peru based on collections from the region of Puno (southern Peru). We include a key to recognize all species of Aristida that grow in Perú.

Anti-inflammatory and Neuropharmacological activities of the seed extract of Setaria italica.

Setaria italica (Poaceae) has been used in folk medicine to treat inflammation, pain, arthralgia and many neurological disorders. The objective of the study is screening of ethanolic extract of Setaria italica seeds for possible anti-inflammatory and neuropharmacological activities in rats and mice respectively. Anti-inflammatory activity was evaluated by carrageenan induced paw edema inhibition method while the neuropharmacological potential was evaluated by three separate methods: Hole-cross test, Open-field method and Phenobarbitone induced sleeping time test. The crude ethanolic extract of seeds of Setaria italica at 400 mg/kg body weight showed a strong anti-inflammatory activity with 20.16, 65.44, 65.5 and 71.15% inhibition of paw edema respectively after 1st, 2nd, 3rd and 4th hrs of carrageenan injection which is comparable to that of standard drug diclofenac sodium at 100 mg/kg body weight (% inhibition 92.3% at 4th hour **P<0.001). In Hole-cross test, ethanolic extracts of Setaria italica at 400 mg/kg body weight dose have prominent CNS depressant activity which is comparable to standard Diazepam. In open field test, S. italica at 400 mg/kg body weight significantly suppressed the movements which is comparable to standard Diazepam. In Phenobarbitone induced test, Setaria italica did not show any significant CNS-depressant activity. The findings of the studies demonstrate anti-inflammatory and neuropharmacological properties of Setaria italica which could be therapeutic option against inflammation and neurological disorders.

Promoção de crescimento de arroz por rizóbios em diferentes níveis de adubação nitrogenada / Growth promotion of rice by rhizobia at different levels of nitrogen fertilization

RESUMO: Embora os rizóbios não apresentem a capacidade de fixar nitrogênio em plantas de arroz, estes podem estimular o crescimento da parte aérea e da raiz, aumentando a absorção de nutrientes, como o nitrogênio, e a produtividade. Com o trabalho, avaliou-se o efeito de rizóbios em promover o crescimento de plantas de arroz em função de doses de nitrogênio (N). Efetuou-se um experimento com vasos contendo solo e plantas da cultivar IRGA 424. As plantas foram inoculadas com oito isolados de rizóbios e adubadas com doses equivalentes a 0, 40, 80 e 160kg N ha-1. Avaliou-se a matéria seca e a quantidade de N acumulada na parte aérea e o perfilhamento das plantas. O efeito do N no crescimento de arroz aumentou com a inoculação de rizóbios. A matéria seca da parte aérea das plantas inoculadas e que receberam, aproximadamente, metade da maior dose de N foi equivalente às que receberam a maior dose desse nutriente e sem inoculação. Além disso, a inoculação com rizóbios aumentou o perfilhamento e a absorção de N. A inoculação de rizóbios em arroz, embora não dispense a adubação nitrogenada, tem potencial para aumentar a produção e a eficiência do uso do N.

ABSTRACT: Although rhizobia do not show the ability to fix nitrogen in rice plants, they can stimulate shoot and root growth and even increase productivity and also can increase the plant efficiency in the absorption of nutrients such as nitrogen. This study evaluated the effect of rhizobia in promoting the growth of rice plants fertilized with nitrogen (N). An experiment was developed in pots containing soil and rice of the cultivar IRGA 424. The plants were inoculated with eight isolates of rhizobia and fertilized with 0, 40, 80 and 160kg N ha-1. We evaluated the dry matter of shoots, tillering and amounts of N absorbed by the shoots. The effect of N on rice growth increased by inoculation of rhizobia. Inoculated plants and fertilized with approximately half of the higher N dose, produced shoot equivalent of the plants that received the highest dose of this nutrient and without inoculation. Moreover, inoculation with rhizobia increased tillering and absorption of N. The practice of rhizobia inoculation in rice, although not replace the nitrogen fertilization, have great potential for rice farmers, allowing greater production and efficiency of N use.

Avaliação dos fitorreguladores auxina e giberelina na germinação e crescimento do arroz / Assessment of auxin and gibberellin on rice germination and growth / Evaluación de fitorreguladores auxina y giberelina en la germinación y crecimiento del arroz

O arroz (Oryza sativa L.) é uma planta da família das Poaceas (gramíneas), sendo um dos cereais mais cultivados no mundo. Os fitorreguladores como auxina e giberilina podem influenciar o crescimento e desenvolvimento das plantas como o arroz. O objetivo deste estudo foi avaliar a germinação e o crescimento do arroz sob diferentes doses de fitorreguladores (auxina e giberelina). Foram conduzidos dois experimentos, o primeiro para determinar a germinação e comprimento radicular das sementes de arroz. O segundo experimento foi conduzido para determinar a altura, massa seca da parte área (MSPA) e o conteúdo nitrogênio (N) da parte aérea (NPA). Nos dois experimentos foram testadas quatro doses de auxina + giberelina: 0 (testemunha); 200; 500 e 1000 mL ha­1. O delineamento experimental foi inteiramente casualizado com cinco repetições para cada tratamento nos dois experimentos. A germinação das sementes e o comprimento radicular foram aumentados com a aplicação de auxina e giberelina. A altura e o NPA foram aumentados significantemente com a aplicação de auxina e giberelina. Concluiu-se que a aplicação de auxina e giberelina na cultura do arroz aumentaram a germinação e o comprimento radicular das sementes. Além disso, aumentou a altura e o conteúdo de nitrogênio nas plantas de arroz.

Rice (Oryza sativa L.) is one of the most widely grown cereals in the world. Phytoregulators such as auxin and gibberellin can influence both growth and development of plants such as rice. The aim of this study was to assess the germination and growth of rice under different doses of phytoregulators (auxin and gibberellin). Two experiments were performed, one to determine the germination and root length of rice seeds, and the second one to evaluated height, shoot dry mass (SDM) and shoot nitrogen content (SNC). Both experiments tested four doses of auxin + gibberellin (0 (control), 200, 500 and 1000 mL ha-1). The experimental design was completely randomized with five repetitions for both experiments. The germination and root length of rice seedlings were increased by the application of auxin and gibberellin. Rice height and SNC were significantly increased with the application of auxin and gibberellin. Thus, it can be concluded that the application of auxin and gibberellin in rice increases germination, root length, plant height and nitrogen content.

El arroz (Oryza sativa L.) es una planta de la familia Poaceas (gramíneas), siendo uno de los cereales más cultivados en el mundo. Los fitorreguladores como auxina y giberelina pueden influir en el crecimiento y desarrollo de plantas, como el arroz. El objetivo de este estudio ha sido evaluar la germinación y el crecimiento del arroz bajo diferentes dosis de fitorreguladores (auxina y giberelina). Se realizaron dos experimentos, el primero para determinar la germinación y longitud de la raíz de las semillas de arroz. Se llevó a cabo un segundo experimento para determinar la altura, masa seca de la parte aérea (MSPA) y el contenido de nitrógeno (N) de la parte aérea (NPA). En ambos experimentos, se ensayaron cuatro dosis de auxina + giberelina: 0 (testigo); 200; 500 y 1000mL ha-1. El diseño experimental fue completamente al azar con cinco repeticiones para cada tratamiento en ambos experimentos. La germinación de las semillas y la longitud de la raíz se incrementaron mediante la aplicación de auxina y giberelina. La altura y el NPA se incrementaron de manera significativa mediante la aplicación de auxina y giberelina. Se concluye que la aplicación de auxina y giberelina en el cultivo de arroz incrementa la germinación y longitud de la raíz de las semillas. Además, incrementó la altura de plantas de arroz con nitrógeno.

Antihyperglycemic and analgesic activity studies with Bambusa spinosa aerial parts.

Bambusa spinosa (Poaceae) is a common type of bamboo found in Bangladesh where it is known as Kata bash. It was of interest to evaluate the antihyperglycemic and analgesic potential of its aerial parts as part of our antihyperglycemic and analgesic plant screening program. In oral glucose tolerance tests, methanol extract of aerial parts of the plant (MEBS) significantly and dose-dependently reduced blood glucose levels in glucoseloaded mice by 37.5, 52.8, 58.3, and 66.8%, respectively, at doses of 50, 100, 200 and 400 mg per kg in comparison to a standard antihyperglycemic drug, glibenclamide, which reduced blood glucose levels by 60.7% at a dose of 10 mg per kg. In acetic acid induced writhing tests in mice, MEBS at the afore-mentioned doses significantly reduced the number of writhings, respectively, by 23.3, 36.7, 46.7, and 60.0% versus the 40.0 and 46.7% reductions observed with a standard analgesic drug, aspirin, at doses of 200 and 400 mg per kg, respectively. MEBS thus demonstrated considerable antihyperglycemic and analgesic properties and may be considered for use to alleviate high blood sugar levels and pain.

Analgesic and antihyperglycemic activity evaluation of Bambusa vulgaris aerial parts.

Bambusa vulgaris, also known as ‘Ora Bansh’ in Bangladesh is grown throughout the country for housing and scaffolding purposes. As part of our analgesic and antihyperglycemic plants of Bangladesh screening program, it was of interest to evaluate the analgesic and antihyperglycemic potential of aerial parts of the plant. Methanolic extract of aerial parts (MEBV) at doses of 50, 100, 200 and 400 mg per kg significantly reduced the number of writhings in acetic acid-induced pain model Swiss albino mice by 25.9, 29.6, 37.0, and 44.4%, respectively compared to reductions of 40.7 and 51.9%, respectively, obtained with 200 and 400 mg per kg of a standard analgesic drug, aspirin. MEBV, at doses of 100, 200 and 400 mg per kg also significantly lowered blood glucose levels in mice, respectively, by 32.8, 45.8, and 55.3% compared to control mice. A standard antihyperglycemic drug, glibenclamide, when administered at a dose of 10 mg per kg lowered blood glucose level by 50.8%. Taken together, the results indicate that the aerial parts of the plant possess considerable analgesic and antihyperglycemic potential, which can possibly be attributed to the presence of alkaloids and saponins in the extract.

Dinâmica de regeneração de Merostachys skvortzovii Send. em remanescente de Floresta com Araucaria / Merostachys skvortzovii Send. regeneration dynamics in a Araucarian forest remnant

Apresentam-se resultados de monitoramento da dinâmica de regeneração de Merostachys skvortzovii Send. (taquara-lixa), englobando dados de recrutamento, crescimento e mortalidade de plântulas (Floresta Ombrófila Mista, General Carneiro, Paraná, 26˚ 25′ S e 51˚ 18′ W). Foram avaliadas duas clareiras de tamanhos (aprox. 40mx40m) e situações de abertura do dossel similares, resultantes da morte de touceiras de taquara-lixa entre 2003-2005, utilizando-se 80 parcelas (1mx1m) em cada clareira (2007). Mensalmente, registrou-se a inclusão, permanência e mortalidade de plântulas de M. skvortzovii nessas parcelas. Evidenciou-se densidade média de plântulas diferenciada, mas similar padrão de distribuição espacial dessas plântulas nas clareiras avaliadas. As médias mensais de recrutamento, crescimento em altura e mortalidade foram significativamente diferentes em ambas as clareiras. Não se detectou correlação significativa entre as variáveis biológicas observadas (crescimento, recrutamento e mortalidade) e a variabilidade de pluviosidade e temperatura registradas no período de monitoramento. Em termos gerais, pode-se inferir que a taquara-lixa apresentava a capacidade de recolonizar as áreas abertas após o evento sincrônico de mortalidade, sendo que as características ambientais de cada clareira podem influenciar essa ocupação. A concentração das plântulas nas bordas das clareiras pode determinar a ampliação da área de ocupação da espécie no local de estudo. Entretanto, somente o monitoramento a médio e longo prazo das clareiras geradas pela morte da taquara-lixa permitirá compreender melhor o ciclo de vida dessa espécie e seu efetivo papel no fechamento dessas clareiras e dinâmica da floresta que a abriga.

The results of monitoring the Merostachys skvortzovii Send. regeneration dynamics, including seedling recruitment, growth and mortality (Araucarian Forest, General Carneiro, Paraná, 26˚ 25′ S e 51˚ 18′ W, 1000m a.s.l.) are presented. Two gaps with similar size (40mx40m) and opening situation, resulting from M. skvortzovii dye-off s in 2003-2005, on which 80 small plots (1mx1m) were evaluated (2007). Monthly, it were registered the inclusion, permanence and mortality of seedlings of M. skvortzovii in these plots. It was evidenced different seedling average density among gaps, but similar seedlings spatial distribution pattern in both gaps. The monthly averages of recruitment, growth in height and mortality were significantly different in both gaps. Significant correlation was not detected between the biological observed variables (growth, recruitment and mortality) and the variability of pluviosity and temperature registered in during the monitoring. In general terms, it is possible to infer that the M. skvortzovii representative were capable of re-colonizing the areas opened after the synchronous dye-off event, but the environmental characteristics of each gap can influence this occupation. The concentration of the seedlings in the edges of the gaps can determine the enlargement of the species occupation area. Meantime, only middle to long term monitoring of the clearings produced by the M. skvortzovii dye-off will allow the understanding of the this species life cycle and its effective paper in the closure of these gaps as well as in the dynamic of the forest that shelters it.

RUST FUNGI ON SOME POACEOUS WEEDS OF WHEAT CROPS IN PAKISTAN.

The article enlists common poaceous weeds found in wheat crop sand their specific parasitic rust fungi. In this study, four (04) plant taxa of Poaceae infected with rust fungi are collected from different wheat crops grown in different areas of Pakistan. The rust fungi are isolated, characterized and identified. All these host plants are known weeds of wheat crop in Pakistan. This work would help to identify and enlist the potential rust fungi on weeds of wheat crop that could be utilized to control these noxious weeds in future.

Protocol optimization and histological analysis of in vitro plant regeneration of RB92579 and RB93509 sugarcane cultivars / Otimização do protocolo e análise histológica da regeneração in vitro de plantas dos cultivares de cana-de-açúcar RB92579 e RB93509

The objectives of this study were to establish appropriate conditions for obtaining plant regeneration and acclimatization of the 'RB92579' and 'RB93509' sugarcane cultivars and to elucidate the shoots origin through histological analysis. For both cultivars, obtaining shoots showed better results with the culture of explants on a callus induction medium containing 2.0mg L-1 2,4-dichlorophenoxyacetic acid, followed by cultivation on a shoot induction medium containing 0.1mg L-1 kinetin and 0.2mg L-1 benzilaminopurine. The MS medium without growth regulators proved to be appropriate for elongation and rooting of shoots and the use of the composed substrate of vermiculite + MS salts was effective for acclimatization. Histological analysis revealed that the origin of the shoots in both cultivars occurred through indirect organogenesis.

Os objetivos deste estudo foram estabelecer condições apropriadas para a obtenção de regeneração de plantas e aclimatização das cultivares 'RB92579' e 'RB93509' de cana-de-açúcar e elucidar a origem das brotações através da análise histológica. Em ambas as cultivares, as brotações obtidas apresentaram os melhores resultados com a cultura dos explantes em um meio de indução de calo contendo 2,0mg L-1 de ácido 2,4-diclorofenoxiacético, seguido do cultivo em meio indutor de brotações, contendo 0,1mg L-1 de cinetina e 0,2mg L-1 benzilaminopurina. O meio MS sem reguladores de crescimento foi adequado para o alongamento e enraizamento das brotações e da utilização do substrato composto de vermiculite + sais do meio MS, foi eficaz para a aclimatização. A análise histológica revelou que a origem das brotações em ambas as cultivares ocorreu via organogênese indireta.

Analysis of vegetation in an Imperata grassland of Barak valley, Assam.

Imperata grassland at Dorgakona, Barak valley, North Eastern India was analyzed for species composition and diversity pattern in relation to traditional management practices. 19 families were in the burnt and unburnt plots of the study site with Poaceae as the most dominant one. 29 species occurred in the burnt plot and 28 in the unburnt plot. Most of the species were common in both the plots. The pattern of frequency diagrams indicated that the vegetation was homogeneous. Imperata cylindrica, a rhizomatous grass was the dominant species based on density (318.75 and 304.18 nos. m-2), basal cover (158.22 and 148.34 cm2 m-2) and Importance value index (IVI) (132.64 and 138.74) for the burnt and unburnt plots respectively. Borreria pusilla was the co-dominant species constituting Imperata-Borreria assemblage of the studied grassland. It was observed that B. pusilla (162.25 nos. m-2 and 50.37 nos. m-2), I. cylindrica (318.75 nos. m-2 and 304.18 nos. m-2) and Setaria glauca (24.70 nos. m-2 and 16.46 nos. m-2) were benefited from burning as shown by the values sequentially placed for burnt and unburnt plots. Certain grasses like Chrysopogon aciculatus and Sacciolepis indica were restricted to burnt plot while Oxalis corniculata showed its presence to unburnt plot. Grasses dominated the grassland as revealed by their contribution to the mean percentage cover of 72% in burnt plot and 76% in unburnt plot. The dominance-diversity curves in the study site approaches a log normal series distribution suggesting that the resources are shared by the constituent species. Seasonal pattern in diversity index suggested definite influence of climatic seasonality on species diversity; rainy season was conducive for maximum diversity (1.40 and 1.38 in the burnt and unburnt plots, respectively). Dominance increased with concentration of fewer species (0.0021 in burnt plot and 0.0055 in unburnt plot) in summer and behaves inversely to index of diversity. This study showed that the traditional management practices benefits the farmers as it promote grassland regeneration with I. cylindrica as the dominant grass.

Germination of native grasses with potential application in the recovery of degraded areas in Quadrilátero Ferrífero, Brazil / Germinação de gramíneas nativas do Quadrilátero Ferrífero com potencial aplicação na recuperação de áreas degradadas

Native grasses are potential species to be used in land rehabilitation. However, due to the lack of better knowledge of their performance, preference is given to exotic plants, which may be invasive and negatively affect the local biodiversity. In order to better understand the propagation of native species of the Quadrilátero Ferrífero (Minas Gerais, Brazil) using their seeds, and in so doing, indicate possible candidates for land rehabilitation, this study investigated the germination patterns of the following grasses: Andropogon bicornis L.; Andropogon leucostachyus Kunth; Setaria parviflora (Poir.) Kerguélen; Cenchrus brownii Roem. & Schult; Echinolaena inflexa (Poir.) Chase, and Apochloa euprepes (Renvoize) Zuloaga & Morrone. The spikelets (depending on the species, removing or not the structures that surround the caryopsis) were treated as follows: T1-Control, T2-moistening with 0.2% potassium nitrate, T3-heating at 80 ºC for 2 minutes, T4-scarification with sulfuric acid (except genus Andropogon) and, for genera Andropogon and Setaria T5-storage at room temperature and T6- refrigerated storage. The treatment was repeated four times for 25 caryopses incubated at 25 ºC and constant light. Significant variation was observed when comparing germination rates from week to week, treatment to treatment and species to species. The most efficient treatment for genus Andropogon was T6, followed by T2 for A. bicornis and T3 for A. leucostachyus. T6 was also the most effective treatment for S. parviflora, followed by T5 and T2. C. brownii showed similar results when applying T1, T2 and T3 (mean 39%). E. inflexa and A. euprepes showed high levels of dormancy that were not overcome by the proposed treatments. A. bicornis, A. leucostachyus, S. parviflora and C. brownii showed higher germination potential, thus being possible candidates for the recovery of degraded areas. Future studies are indicated to find the most effective treatments for germination in field conditions.

As gramíneas nativas apresentam potencial para revegetação de áreas degradadas, no entanto, devido ao pouco conhecimento sobre sua biologia, dá-se preferência ao uso de espécies exóticas, que podem ser invasoras, afetando assim a biodiversidade local. No intuito de ampliar o conhecimento acerca da propagação via sementes de espécies nativas do Quadrilátero Ferrífero (QF), e desta forma, indicar possíveis candidatas a aplicação na recuperação de áreas degradadas da região, este trabalho objetivou avaliar os padrões germinativos das seguintes gramíneas: Andropogon bicornis L.; Andropogon leucostachyus Kunth; Setaria parviflora (Poir.) Kerguélen, Cenchrus brownii Roem. & Schult; Echinolaena inflexa (Poir.). Chase e Apochloa euprepes (Renvoize) Zuloaga & Morrone. As espiguetas (com presença ou não das estruturas que envolviam a cariopse, dependendo da espécie) foram submetidas aos seguintes tratamentos: T1-controle; T2-umedecimento do substrato com 0,2% de nitrato de potássio, T3-aquecimento a 80 ºC por 2 minutos, T4-escarificação com ácido sulfúrico (exceto gênero Andropogon) e para os gêneros Andropogon e Setaria, T5-armazenamento a temperatura ambiente e T6-armazenamento sob refrigeração. Os tratamentos foram realizados em 4 repetições de 25 cariopses colocadas para germinar a temperatura de 25 ºC e iluminação constante. Variação significativa foi observada quando comparadas as quantidades de germinações ocorridas entre as semanas, entre os tratamentos e entre as espécies. Para o gênero Andropogon o tratamento mais eficiente foi T6, seguido por T2 em A. bicornis e T3 em A. leucostachyus. T6 também foi o tratamento mais eficiente para S. parviflora, seguido por T5 e T2. C. brownii apresentou resultados próximos sob T1, T2 e T3 (média 39%). E. inflexa e A. euprepes apresentaram altos índices de dormência que não foram superadas pelos tratamentos propostos. A. bicornis, A. leucostachyus, S. parviflora e C. brownii apresentaram maiores potenciais de germinação, sendo possíveis candidatas para recuperação de áreas degradas no QF. No entanto, ainda são necessários estudos complementares com os tratamentos mais eficientes e testes de germinação e estabelecimento em condições de campo.

Ultraestructura de la epidermis foliar de Zeugites (Poaceae: Panicoideae)

Leaf epidermis ultrastructure of Zeugites (Poaceae: Panicoideae). The genus Zeugites comprises eleven species of neotropical grasses and it is principally distributed in Mexico, with some species extending to the Caribbean region, Central and South America. In this work, leaf epidermis ultrastructure of 11 species is described by the use of scanning electron microscopy. At least three specimens per species, that included herbarium and collected specimens, were used. An identification key and specific descriptions are included, in which the distinctive epidermal features are highlighted. The taxonomic valuable characters found were the following: presence or absence of prickles and macrohairs, intercostals short cells form and silica body form. Based on leaf epidermis characteristics, Zeugites species can be arranged into three groups: (1) species that lack prickles (Z. americana, Z. mexicana, Z. pringlei, Z. munroana and Z. sagittata); and lack macro hairs, with the exception of Z. pringlei; (2) species that have prickles (Z. latifolia and Z. smilacifolia); (3) species that have both, prickles and macrohairs (Z. capillaris, Z. hackelii, Z. pittieri and Z. sylvatica). The morphological features of leaf epidermis, support the relationship between the tribes Centotheceae and Paniceae. Rev. Biol. Trop. 59 (2): 557-568. Epub 2011 June 01.

El género Zeugites incluye once especies de pastos con distribución neotropical, en México, el Caribe, Centro y Sudamérica. En este trabajo se describe la epidermis foliar de las once especies, se utilizaron técnicas de microscopía electrónica de barrido y revisaron al menos tres especímenes de cada especie, algunas muestras proceden de ejemplares de herbario y otras fueron recolectadas por la primera autora. Se presenta una clave y descripciones para las especies del género, en las cuales se resaltan las características epidérmicas distintivas. Los caracteres que resultaron informativos, desde el punto de vista taxonómico fueron: la presencia o ausencia de aguijones y macropelos, la forma de las células cortas intercostales y la forma de los cuerpos de sílice. Con base en estas características, las especies de Zeugites se pueden separar en tres grupos: (1) especies que no presentan aguijones (Z. americana, Z. mexicana, Z. pringlei, Z. munroana y Z. sagittata) y que con excepción de Z. pringlei tampoco presentan macropelos; (2) especies que presentan sólo aguijones (Z. latifolia y Z. smilacifolia); y (3) especies que presentan aguijones y macropelos (Z. capillaris, Z. hackelii, Z pittieri y Z. sylvatica). Las características morfológicas de la epidermis foliar, sustentan la relación de las tribus Centotheceae y Paniceae.

Qualidade forrageira do capim-capivara em áreas de várzea, na região central do Rio Grande do Sul, Brasil / Forage quality of 'capim-capivara' on lowlands in the central region of Rio Grande do Sul, Brazil

Hymenachne amplexicaulis (capim-capivara) é uma gramínea semi-aquática, estolonífera, que pode estabelecer densas formações em ambientes que se inundam e nas margens de rios em regiões tropicais e subtropicais. Com o objetivo de determinar a qualidade bromatológica e a digestibilidade de H. amplexicaulis presente em áreas de várzea, foram realizadas coletas nos municípios de Formigueiro, Santa Maria e São Vicente do Sul, municípios da Depressão Central do Rio Grande do Sul, Brasil. Foram determinados os teores de matéria seca (MS), proteína bruta (PB), fibra em detergente ácido (FDA), fibra em detergente neutro (FDN), matéria orgânica (MO), matéria mineral (MM) e digestibilidade in vitro da matéria orgânica (DIVMO), que apresentaram valores médios 23,24 por cento, 7,42 ( por centoMS), 67,01 ( por centoAMS), 35,75 ( por centoMS), 91,44 ( por centoMS), 8,55 ( por centoMS) e 55,41 por cento (DIVMO), respectivamente. H. amplexicaulis, coletado em áreas de várzea na região central do RS, apresenta qualidade bromatológica para uso na alimentação animal, apesar dos reduzidos valores de proteína bruta e digestibilidade encontrados no estádio avaliado.

Hymenachne amplexicaulis (capim-capivara) is a semi-aquatic stoloniferous grass which forms dense monospecific stands in seasonally flooded environments and along riverbanks in tropical and subtropical wetlands. For determining the bromatologic quality and digestibility of Hymenachne amplexicaulis grass placed in lowlands, samples were collected in Formigueiro, Santa Maria and São Vicente do Sul, municipalities of Rio Grande do Sul, Brazil., Dry matter (DM), crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), organic matter (OM), mineral matter (MM), and organic matter digestibility (DOM) levels were determined in laboratory. The results for these variables, in mean values, were 23.24 percent, 7.42 ( percentDM), 67.01 ( percentDM), 35.75 ( percentDM), 91.44 ( percentDM), 8.55 ( percentDM) and 55.41 percent (DIVMO) respectively. H. amplexicaulis, sampled on Depressão Central lowland areas, has bromatologic quality for animal feeding; despite reduced both crude protein and digestibility values found at the stage evaluated.

Efeito da aplicação de silicato de cálcio em Brachiaria rizantha cv. Marandu sobre a população de ninfas do percevejo castanho das raízes Scaptocoris carvalhoi Becker, 1967, características químicas do solo, planta e produção de matéria seca / Application effect of calcium silicate in Brachiaria brizantha cv. Marandu on the nymph population of the brown root stinkbug, soil chemical characteristics, and plant and dry matter production

Neste trabalho, objetivou-se avaliar o efeito de diferentes doses de silicato de cálcio sobre a população de ninfas de percevejo castanho das raízes em Brachiaria brizantha, nas características químicas do solo, planta e produção de matéria seca. O experimento foi conduzido em blocos casualizados, com cinco tratamentos e quatro repetições, totalizando 20 parcelas. Os tratamentos testados foram cinco doses (0, 0,5, 1, 2, e 4 t ha-1) de silicato de cálcio aplicadas junto com a adubação NPK na implantação da B. brizantha. Foi avaliado o número de ninfas do percevejo (profundidade de 0 a 40 cm), o pH e os teores de cálcio e de silício no solo. Aos 120 dias do plantio, a gramínea foi cortada, determinando-se a composição química e a produção de massa seca. Verificou-se que a aplicação de 2,6 t ha-1 de silicato de cálcio foi a melhor dosagem estimada para a redução de ninfas do percevejo castanho das raízes. A aplicação de doses crescentes de silicato de cálcio no solo promoveu o incremento do pH, dos teores de cálcio e silício no solo e o aumento na produção de matéria seca de B. brizantha.

The objective of this study was to evaluate the effects of different calcium silicate rates on the nymph population of the brown root stinkbug in B. brizantha cv. marandu, in the soil chemical characteristics, and plant and dry matter production. The experiment was carried out in casualized blocks with five treatments and four repetitions, in a total of 20 plots. The treatments tested were five rates (0, 0.5, 1, 2, and 4 t ha -1) of calcium silicate applied together with NPK fertilization in the implantation of B. brizantha. The nymph number (depths 0 to 40 cm), pH, and soil calcium and silicon content were evaluated. On the 120th day after sowing, the grass was cut to determine the chemical composition and dry matter production. It was verified that the application of 2.6 t ha -1 of calcium silicate was the best estimated rate for the reduction of brown root stinkbug nymphs. The application of increasing doses of calcium silicate in the soil caused an increase of the pH, calcium and silicon content in the soil, and an increase in B. brizantha dry matter production.