RESUMO: Uma das formas de se obter conhecimento sobre as diferenças e semelhanças entre os comportamentos das sementes ortodoxas e recalcitrantes durante o processo de maturação é analisando as fases imaturas das sementes ortodoxas e as variações em suas características, conforme as condições ambientais nas quais foram formadas. Diante disto, neste trabalho, os frutos de Erythrina speciosa Andrews foram coletados em Florianópolis (SC), Lajeado (RS) e São Paulo (SP) entre os meses de agosto e novembro. As sementes, extraídas, foram classificadas em seis estádios diferentes de maturação. Armazenadas a 7 °C, e os experimentos realizados iniciaram em até cinco dias. O teor de água e a massa seca foram medidos pelo método da estufa a 103 ± 3 °C. A germinação foi analisada a 25°C e 70% de umidade relativa, com avaliações a cada dois dias por 30 dias. Para indução de dormência, as sementes foram secas até 10% de água. A análise estatística usou ANOVA e teste de Tukey a 5%. Observou-se que as sementes imaturas apresentaram grandes variações de comportamento em função de época e local de coleta, para uma mesma idade cronológica, reforçando a ideia de que variações no comportamento das sementes podem ser decorrentes do seu grau de maturação no momento em que são dispersas. RESUMO características formadas disto trabalho SC, SC , (SC) RS (RS SP (SP novembro extraídas C °C 10 25C 25 70 relativa dormência 5 5% Observouse Observou coleta cronológica dispersas (SC 1 2

ABSTRACT: Analyzing unripe phases of orthodox seeds and the variations in traits depending on environmental conditions under which they were formed is a way of gaining knowledge on the differences and similarities between orthodox and recalcitrant seed behavior. From this perspective, in this study fruits of Erythrina speciosa Andrews were collected in Florianópolis (SC), Lajeado (RS) and Sao Paulo (SP) in August and November. Seeds were extracted and classified into six different maturation stages. Seeds were stored at 7 °C for a maximum of five days until the beginning of the experiments. Moisture content and dry matter content were measured through the oven method (103 ± 3 °C). Germination was analyzed at 25 °C and 70% of relative humidity, with evaluations being made every two days for 30 days. To induce dormancy, seeds were dried to 10% moisture content. We ran an analysis of variance (ANOVA) and Tukey’s test at 5% as statistical analysis. We observed that unripe seeds showed a wide behavior variation depending on the collection period and site, for a same chronological age, reinforcing the idea that the seed behavior variation may be due to the maturation degree at the moment of seed dispersal. ABSTRACT perspective SC, SC , (SC) RS (RS SP (SP November stages C experiments 103 (10 °C. . °C) 2 70 humidity dormancy 10 ANOVA (ANOVA Tukeys Tukey s 5 site age dispersal (SC (1 1 (

Abstract Riverine forests have high floristic diversity and are heterogeneous, even when they are near each other. Therefore, we aimed to compare three riverine forest remnants of Southern Brazil located in the Pampa biome regarding floristic and structural biodiversity, to: i) check whether the studied forest fragments maintain heterogeneity and high floristic richness as seen in riverine forests, even when close to each other, and ii) indicate the predominant successional groups in each remnant. A total of 81 sampling units were established, and all trees with diameter at breast height ≥ 15 cm were measured. We sampled 1,659 individuals, 67 species, and 34 families. The richness and structure of the three communities differed, confirming the high heterogeneity of riverine forests. One of the remnants had a higher predominance of pioneer species and individuals, which differentiated it from the other two. The latter, in turn, showed higher similarity in floristic and structural composition, with a predominance of secondary and late successional individuals and species. Differences in soil moisture, in the size and shape of fragments may be factors that contributed to the floristic and structural diversity observed. The remnants, although small and surrounded by monocultures, are heterogeneous and important for biodiversity conservation. Therefore i ii remnant 8 established 1 measured 1659 659 1,65 6 3 families differed two latter turn composition moisture observed monocultures conservation 165 65 1,6 16 1,

Resumo O estudo objetivou identificar o substrato e o tipo de estaca adequados para a obtenção de mudas por estaquia de Baccharis vulneraria Baker. Foram coletadas estacas apicais e caulinares de plantas matrizes mantidas em casa de vegetação e cultivadas nos substratos: substrato comercial à base de turfa (CPS); Vermiculita (VM); casca de arroz carbonizada (CRH); Fibra de coco (CF); VM e CRH (1:1) (VM + CRH); VM e CF (1:1) (VM + CF); CRH e CF (1:1) (CRH + CF). O delineamento foi inteiramente casualizado em esquema fatorial e, após 60 dias foi avaliado: percentual de sobrevivência e enraizamento (% SR), comprimento da parte aérea (APL) de raízes (RSL), número de brotos (SN) e de folhas novas (LN), volume de raiz (RSV), massa seca da parte aérea (APDM) e de raízes (RSDM). Houve interação entre o tipo de substrato e estaca para APL, RSL, LN, RSV e RSM. Já %SR, SN e APDM diferiram somente para o tipo de estaca. Estacas apicais apresentaram maior APL enquanto as de entrenó demonstraram maior SN, LN, RSV e APDM. CPS promoveu maior CSR nos dois tipos de estacas, sendo uma opção adequada para propagação de Baccharis vulneraria, principalmente em estacas de entrenó. Baker substratos (CPS) (VM) (CRH) (CF) 11 1 (1:1 CRH) CF) CF. . 6 avaliado % ( SR, SR , SR) (APL RSL (RSL) (SN LN (LN) RSV, (RSV) (APDM RSDM. RSDM (RSDM) RSM %SR (CPS (CF (1: (RSL (LN (RSV (RSDM (1

Abstract The objective of the study was to identify the most suitable substrate and type of cutting to obtain seedlings from Baccharis vulneraria Baker cuttings. Apical and stem cuttings were collected from stock plants grown in a greenhouse. After collection, the cuttings were grown in the following substrates: commercial peat-based substrate (CPS); Vermiculite (VM); carbonized rice husk (CRH); Coconut fiber (CF); VM and CRH (1:1) (VM + CRH); VM and CF (1:1) (VM + CF); and CRH and CF (1:1) (CRH + CF) mixtures. The experiment used a completely randomized factorial design and, after 60 days, the percentage of survival and rooting (% SR), aerial part length (APL) and roots length (RSL), number of shoots (SN) and new leaves (LN), root volume (RSV), aerial part dry mass (APDM), and roots dry mass (RSDM) were evaluated. An interaction was found between the type of substrate and cutting for APL, RSL, LN, RSV, and RSM. On the other hand, %SR, SN and APDM differed only by cutting type. Apical cuttings showed higher APL, while internode cuttings showed higher SN, LN, RSV, and APDM. CPS promoted higher RSL in both types of cuttings, being a suitable option for the propagation of Baccharis vulneraria, particularly in internode cuttings. greenhouse collection substrates peatbased peat based (CPS) (VM) (CRH) (CF) 11 1 (1:1 CRH) mixtures 6 days % ( SR, SR , SR) APL (APL (RSL) (SN LN (LN) RSV (RSV) APDM, (APDM) RSDM (RSDM evaluated RSM hand %SR (CPS (CF (1: (RSL (LN (RSV (APDM (1

RESUMO Mudas de erva-mate com qualidade genética e fisiológica, altos índices de sobrevivência no plantio e resistência a estresses ambientais são necessários para a implantação e estabelecimento de ervais produtivos que irão fornecer matéria-prima de qualidade. No entanto, a produção de mudas, na maioria dos casos, é realizada a partir de sementes, as quais são coletadas de plantas matrizes com poucos critérios de seleção. Nesse sentido, o trabalho teve como objetivo investigar a qualidade das sementes de erva-mate após pré-limpeza por flutuação de diferentes plantas matrizes, por meio da obtenção de informações sobre a caracterização biométrica (medida longitudinal e transversal), teor de água, peso de mil sementes, avaliação da integridade das sementes e viabilidade por meio do teste de tetrazólio. As sementes foram coletadas de 10 plantas matrizes localizadas em três municípios da região ervateira Alto Vale do Taquari - RS, Brasil. Na avaliação da integridade foram contabilizadas a quantidade de sementes não íntegras (vazias e deterioradas) e íntegras (com e sem embrião visível). E no teste de tetrazólio foi avaliada a porcentagem de sementes viáveis e não viáveis. As sementes das diferentes plantas matrizes apresentaram diferenças estatísticas para todas as variáveis analisadas. As análises mostraram que há diferenças relacionadas à biometria e teor de água e, consequentemente, no peso de mil sementes. A erva-mate apresenta percentual variado de sementes vazias e deterioradas. A porcentagem de sementes não viáveis é alta, o que reduz significativamente a viabilidade de um lote de sementes.

ABSTRACT Yerba mate seedlings with genetic and physiological quality, high rates of sowing survival and resistance to environmental stresses are necessary for the implantation and establishment of productive plants that will provide quality raw material. However, the production of seedlings, in most cases is carried out from seeds, which are collected from mother-plants with few selection criteria. In this sense, the work aimed to investigate the quality of the seeds of yerba mate after processing by flotation from different mother-plants, by obtaining information about the biometric characterization (longitudinal and transversal measure), water content, a thousand-seed weight, evaluation of the seed integrity and viability through the tetrazolium test. The seeds were collected from 10 mother-plants located in three cities in the yerba-mate region Alto Vale do Taquari - RS state, Brazil. In the integrity assessment, the number of not full (empty and deteriorated) and full (with and without visible embryo) seeds was counted. In the tetrazolium test, the percentage of viable and non-viable seeds was evaluated. The seeds of the different parent plants showed statistical differences for all the variables analyzed. The analysis showed that there are differences related to biometric parameters and water content and, consequently, in the weight of a thousand seeds. Yerba mate shows a varied percentage of empty and deteriorated seeds. The percentage of non-viable seeds is high, which significantly reduces the viability of the seed lot.

Resumo As plantas alimentícias não convencionais têm uma variedade de compostos bioativos com valor nutricional. O jaracatiá (Vasconcellea quercifolia) pertence à família Caricaceae e é uma alternativa dietética com uma excelente composição nutricional. Este estudo teve como objetivo caracterizar a composição nutricional da farinha de frutos verdes do jaracatiá (V. quercifolia), a fim de aplicá-la em um alimento funcional. Para isso, a farinha foi caracterizada em relação a macro e micronutrientes, fatores antinutricionais, pH, atividade da água e cor. Esta farinha apresentou teores de carboidratos de 22,31%; proteínas de 9,65%; fibra alimentar dietética de 32,80%; lipídios de 14,95%, dos quais 63,56% são ácidos graxos insaturados, especialmente ácido oleico; e cinzas de 9,10%, com maiores concentrações para potássio, cálcio e magnésio. Portanto, a farinha de V. quercifolia tem características nutritivas e pode ser utilizada como suplemento alimentar.

Abstract Non-conventional food plants have a variety of bioactive compounds with nutritional value. Vasconcellea quercifolia A. St.-Hil., belonging to the Caricaceae family, is a dietary alternative with excellent nutritional composition. This study aimed at characterizing the nutritional composition of mountain papaya (V. quercifolia) green fruit flour, in order to incorporate it in a functional food. For that purpose, the flour was characterized regarding its macro and micronutrients, anti-nutritional factors, pH, water activity, and color. This flour showed contents of carbohydrate of 22.31%; protein of 9.65%; dietary fiber of 32.80%; lipids of 14.95%, 63.56% of which are unsaturated fatty acids, especially oleic acid; and ash of 9.10%, with higher concentrations for potassium, calcium and magnesium. Therefore, V. quercifolia flour had good nutritional characteristics and might be used as supplementary food.

Abstract This study evaluated the effect of disinfestation methods and different storage environments on the germination of seeds of Limonium brasiliense (Boiss.) Kuntze. Seeds were disinfested using ethanol followed by sodium hypochlorite; water under agitation; and no disinfestation from two origins. Longevity was tested by storing the seeds in a cold chamber, dry chamber, and at ambient laboratory temperature. Beginning of germination (BG), percentage (%G), and mean germination time (MGT) and mean germination speed index (MGSI) were evaluated. Data were submitted to an analysis of variance, comparison of mean values and a polynomial regression analysis (p<0.05). In the disinfestation, there was significant difference in %G and MGT only between origins. For longevity, IG and MGSI had a positive and negative linear behavior, respectively, while %G had a quadratic behavior. L. brasiliense seeds disinfestation does not affect germination. Dry chamber was the most suitable storage environment.

ABSTRACT Agroforestry systems (AFS) represent an alternative to the current agricultural model, based on monoculture, mechanization, and intensive use of agrochemicals. The aim of this study was to characterize existing AFS in the Southern region of Brazil and understand how their forestry certification process is conducted by the official governmental body (SEMA-RS). Interviews were carried out with the owners of five AFS and one technical visit was made to SEMA-RS. Changes in production model resulted from a process of raising farmers’ awareness, which was observed when the main reason mentioned by farmers for implementing AFS is to ensure a healthier life quality. Another reason mentioned is that this system is economically and environmentally feasible and complies with current legislation. On the other hand, SEMA-RS facilitated the certification process by developing a simplified and quicker modality for AFS. The support of technicians and associations helps by providing access to information and to a successful production. This study confirms the effectiveness of AFS and the need to further their visibility so that they are implemented in other locations, especially in degraded areas, thus contributing with environmental preservation and with improving the health of the population, from farmers to consumers.

Resumo As matas ripárias são importantes corredores de biodiversidade entre os grupos. Essas florestas foram muito alteradas ou suprimidas no estado do Rio Grande do Sul. Este estudo investiga a variação da riqueza de espécies e distribuição de samambaias e licófitas de dezoito áreas de estudo em diferentes estágios de sucessão em matas ripárias da região do rio Taquari. Amostras de samambaias e licófitas foram coletadas utilizando a metodologia de caminhamento ao longo do rio Taquari durante dois anos. A riqueza foi comparada nos diferentes estágios de sucessão (formações remanescentes avançadas, intermediárias e iniciais) por meio de análise de variância e um teste randomizado, no qual foram registradas cerca de 22 espécies: 19 espécies estavam em estágio avançado de sucessão, nove espécies estavam no estágio intermediário e sete espécies estavam em estágio inicial de sucessão. A riqueza média foi significativamente maior nas áreas em estágio avançado de sucessão. O alto valor das espécies comuns encontradas nos estágios intermediários destaca a importância da preservação das matas ripárias em todos os estágios de sucessão do rio Taquari como alternativa para preservação da biodiversidade local.

Abstract Riparian forests are important biodiversity corridors among groups. Such forests were greatly altered or suppressed in the state of Rio Grande do Sul. This study investigates the variation of species richness and distribution of ferns and lycophytes of eighteen study areas at different stages of succession in riparian forests of the Taquari River region. Fern and lycophyte samples were collected using the pathway methodology along the Taquari River during two years. The richness was compared at the different succession stages (advanced remnant formations, intermediate and initial) through analysis of variance and a randomized test, in which about 22 species were recorded: 19 species were at the advanced stage of succession, nine species were at the intermediate stage and seven species were at the initial stage of succession. The average richness was significantly higher in areas at advanced stage of succession. The high value of common species found at intermediate stages highlights the importance of preserving riparian forests at all stages of succession in the Taquari River as alternative for preserving the local biodiversity.

Abstract Vasconcellea quercifolia A.St-Hil. (Caricaceae) is a non-conventional food plant (PANC) of Brazil. The aim of this study was to investigate the physical, chemical, and nutritional properties of green and ripe fruits and medullary parenchyma of V. quercifolia A.St-Hil., in order to develop functional foods. We determined humidity, pH, ash content, protein content, carbohydrate content, fibre content, carotenoid content, ascorbic acid content, and aminograms of green and ripe fruits and of medullary parenchyma from three specimens, following existing methodologies. Green fruits had higher protein and fibre contents, and ripe fruits had higher ash, carbohydrate, and carotenoid contents, higher than other most consumed fruits. On the other hand, medullary parenchyma had higher ash content and humidity. Glutamic acid, aspartic acid, and lysine were the amino acids with the highest contents, mainly in green fruits. Aside from medullary parenchyma, used as food in the past, both green and ripe fruits can be used for the development of new food products with functional properties and potential for new alternatives for consumption.

Lupinus albescens é uma espécie frequente nos locais de arenização no Rio Grande do Sul, com alta rusticidade e rápida cobertura vegetal, mostrando potencialidades para recomposição de áreas degradadas. O objetivo foi avaliar a emergência e o desenvolvimento de L. albescens, com e sem aplicação de adubação mineral consorciada com a palmeira Butia lallemantii Deble & Marchiori. Sementes foram coletadas em três populações e submetidas à escarificação por 40 segundos. A sementeira foi feita entre nove fileiras (2 x 1 m) de B. lallemantii aplicando-se 0 e 30 g/cova do fertilizante mineral NPK (5-20-20). Avaliações: número de plantas por cova (NPC), altura (cm) e diâmetro do caule (mm), nos períodos de 30 e 60 dias, assim como a percentagem de emergência de plantas/m² (PEP) e o total emergência de plantas (TEP) ao longo de 240 dias, utilizando delineamento em blocos casualizados. Os resultados mostraram considerável PEP e altura aos 30 dias para as plantas do bloco 2. Dose de 0g/cova do fertilizante NPK proporcionou maior NPH. Portanto, a sementeira de L. albescens consorciada com B. lallemantii apresentou maior PEP, NPC sem o uso de adubação (30 dias) e maior altura das plantas entre as plântulas de diâmetro do estipe médio.

Lupinus albescens is a species frequent in the locals under arenization in Rio Grande do Sul, with high rusticity and rapid land cover, showing potentialities for recomposition of degraded areas. The objective was to evaluate the emergence and development of L. albescens, with and without mineral fertilizer application intercropped with the palm Butia lallemantii Deble & Marchiori. Seeds were collected in three populations and submitted to the scarification for 40 seconds. Sowing was done between nine rows (2 x 1 m) of B. lallemantii by applying 0 and 30 g/hole of the mineral fertilizer NPK (5-20-20). Evaluations: number of plants per hole (NPH), height (cm) and stem diameter (mm), in the periods of 30 and 60 days, as well as the percentage of plants emergence/m² (PEP) and the total of plants emergence (TEP) over 240 days, using randomized block design. The results showed a considerable PEP and height at 30 days for the plants in block 2. Dose of 0g/hole of fertilizer NPK provided higher NPH. Therefore, sowing of L. albescens intercropped with B. lallemantii presented higher PEP, NPH without the use of fertilization (30 days) and higher height of the plants among the diameter seedlings of the medium stipe.

In South American folk medicine members of the genus Myrciaria are used for the treatment of malaria, diarrhoea, asthma, inflammation and post-partum uterine cleansing. The aim of this work was to evaluate its antileishmanial properties (in vitro) of essential oil derived from leaves of Myrciaria plinioides D. Legrand, a plant species that is native in South of Brazil. The essential oil was obtained by hydro-distillation using fresh leaves of M. plinioides. The chemical composition of this essential oil (MPEO, M. plinioides essential oil) was determined by gas chromatography coupled to mass spectrometry (GC-MS). MPEO was assayed in vitro for antileishmanial properties against promastigotes of Leishmania amazonensis and Leishmania infantum, and for cytotoxicity against murine peritoneal macrophages. The MPEO comprised 66 components and was rich in oxygenated sesquiterpenes (82.66%) containing spathulenol (21.12%) as its major constituent. The MPEO was effective against L. amazonensis with IC50 value of 14.16 ± 7.40 µg/mL, while against L. infantum the IC50 value was higher with 101.50 ± 5.78 µg/mL. The MPEO showed significant activity against L. amazonensis, and presented a selectivity index (SI) of 6.60. The results suggest that the essential oil from leaves of M. plinioides is a promising source for new antileishmanial agents against L. amazonensis.

RESUMO Asteraceae é a maior família das angiospermas e ocorre predominante em áreas campestres. Este estudo buscou identificar e caracterizar os tricomas foliares de 34 espécies de Asteraceae dos Campos de Areais do bioma Pampa por meio de análises da epiderme (vista frontal e transversal) em microscopia de luz e eletrônica de varredura. Foram identificados e caracterizados 11 tipos de tricomas: três glandulares (recurvado, capitado ereto e capitado vesicular unisseriado a multisseriado) e oito tectores (cônico simples, filiforme-flagelado, asseptado-flagelado, forma de chicote, oblíquo-flagelado, ramificado com um braço, ramificado com dois braços em forma de T, ramificado com três ou mais braços). O tipo de tricoma glandular mais representativo foi o capitado vesicular unisseriado a multisseriado (58%) e o tipo não glandular (tector) foi o cônico simples (35%). A grande quantidade de tricomas é uma estratégia adaptativa às condições adversas do bioma Pampa e a sua diversidade morfológica pode ser útil na sistemática da família.

ABSTRACT Asteraceae is the largest family of angiosperms and occurs predominantly in grassland areas. This study aimed to identify and characterize the foliar trichomes of 34 Asteraceae species from Sand-fields of the Pampa biome, by means of epidermal analyzes (front and transverse view) under light and scanning electron microscopy. Eleven types of trichomes were identified and characterized: three glandular (recurved on the epidermis, erect-capitate and uniseriate to multiseriate vesicular-capitate) and eight non-glandular (simple conical, flagellate-filiform, aseptate-flagellate, whip-like, oblique-flagellate, branched with one arm, branched with two T-shaped arms, branched with three or more arms). The most representative glandular type was the uniseriate to multiseriate vesicular-capitate (58%) and the non-glandular type was the simple conical (35%). A large number of trichomes is an adaptive strategy to the adverse conditions of the Pampa biome and its morphological diversity can be useful in the family systematics.

Resumo Algumas espécies exóticas vêm ameaçando a integridade dos ecossistemas naturais pelo seu potencial invasor. Elas podem ser favorecidas pelo lançamento de compostos secundários no solo. Morus nigra (Moraceae) é uma espécie invasora de florestas ribeirinhas no sul do Brasil. O objetivo do estudo foi verificar se o extrato aquoso dos frutos e folhas frescas e secas apresentam efeitos fitotóxicos sobre a germinação, o crescimento e a integridade de membranas de plântulas de Lactuca sativa. Foram testadas as concentrações 0,1; 0,25; 0,5; 0,75; 1; 2,5; 5; 7,5 e 10%. A taxa e o índice de velocidade de germinação foram definidos. O crescimento inicial foi obtido com as medidas do comprimento de raiz e parte aérea. A integridade das membranas foi estimada através de medidas de condutividade. Os resultados evidenciaram os efeitos fitotóxicos dos extratos aquosos, causando a inibição significativa da germinação e no crescimento inicial das plântulas. Os efeitos fitotóxicos dos extratos das folhas frescas e secas foram superiores ao do fruto. Além disso, os extratos causaram alterações na estrutura das membranas e deformações morfológicas nas plântulas, como radículas necrosadas e plantas acloríticas. A alta fitotoxidez dos extratos M. nigra foi evidenciada, indicando o seu potencial alelopático.

Abstract Some exotic species threat the integrity of natural environments due to their invasive potential. They can affect other species by releasing secondary compounds in the soil. Morus nigra (Moraceae) is an invasive species of riparian forests in southern Brazil. The objective of this study was to verify if the aqueous extracts of fruit, fresh and dry leaves of M. nigra show phytotoxic effects on germination, seedling growth and membrane integrity of seedlings of Lactuca sativa. Extract concentrations of 0.1, 0.25, 0.5, 0.75, 1, 2.5, 5, 7.5 and 10% were tested. Germination rate and speed of germination were determined. Effects on initial growth were evaluated by measuring seedling root and shoot length, and membrane integrity was assessed by conductivity tests. Results showed the phytotoxicity of M. nigra aqueous extracts, causing significant inhibition on germination and seedling growth. The fruit extract was generally less phytotoxic than extracts from fresh and dry leaves. Moreover, the extracts induced changes in membrane integrity and caused morphological deformities in seedlings, such as necrotic roots and chlorotic plants. The high phytotoxicity of fruit, dry and fresh leaf extracts of M. nigra was evidenced, indicating the allelopathic potential of the species.

RESUMO Com o objetivo de caracterizar a estrutura da comunidade arbórea de um remanescente de floresta ribeirinha do rio Taquari, foram estabelecidas 42 unidades amostrais de 100 m2 (10 × 10 m) e calculados os parâmetros fitossociológicos e índices de diversidade de Shannon (H') e Equabilidade de Pielou (J). Foram amostradas 39 espécies, 21 famílias, 2,83 para H' e 0,77 para J. Dentre as espécies Callisthene inundata O.L. Bueno, A.D. Nilson & R.G. Magalh. é endêmica, estando, junto com Picrasma crenata (Vell.) Engl., na lista das espécies ameaçadas de extinção. A densidade encontrada foi de 1.557,14 ind. ha-1. Luehea divaricata Mart. e Lonchocarpus nitidus Benth. apresentaram os maiores índices de valores de importância. Além de contribuir para o conhecimento da distribuição das espécies e estrutura da comunidade, este estudo alerta para a necessidade de conservação dos remanescentes florestais nativos existentes.

ABSTRACT Aiming to characterize the structure of the arboreal community in a riverine forest remnant of the Taquari river, State of Rio Grande do Sul, 42 sampling units of 100 m2 (10 × 10 m) were located. Phytosociological parameters were also assessed and the indexes of Shannon diversity (H') and Pielou evenness (J) were evaluated. A total of 39 species, 21 families, 2.83 nats ind-1 for H' and 0.77 for J were recorded. Among the species found, the endemic Callisthene inundata O.L. Bueno, A.D. Nilson & R.G. Magalh. and Picrasma crenata (Vell.) Engl. are included in the list of endangered species. The density found was of 1,557.14 ind ha-1. Luehea divaricata Mart. and Lonchocarpus nitidus Benth. showed the highest indexes of importance values. Besides contributing to the knowledge of species distribution and community structure, this study points out the need for conservation of existing native forest remnants.

Resumo A dispersão de sementes é um processo fundamental à manutenção de ecossistemas florestais, favorecendo o sucesso germinativo de plantas em locais adequados ao seu crescimento, minimizando a competição, a ação de patógenos e a predação por herbívoros. Variações intra-específicas e sazonais no consumo de frutos por Didelphis albiventris, bem como sua contribuição à dispersão e germinação de sementes endozoocóricas foram avaliados em Floresta Estacional Semidecidual. O estudo foi realizado no Morro do Coco, localizado no município de Viamão, RS às margens do Lago Guaíba (30º16’15”S, 51º02’54”W), entre junho de 2013 a maio de 2014, resultando em um esforço amostral de 2992 armadilhas-noite. Foram capturados 18 indivíduos e coletadas 24 amostras fecais. Frutos estiveram presentes em 96% das amostras e corresponderam a 18 espécies vegetais, pertencentes a 10 famílias. As espécies mais frequentes foram Ficus cestrifolia e Syagrus romanzoffiana, que ocorreram em 66% das amostras, seguidas de Banara parviflora e Cecropia pachystachya, ambas com 25% de ocorrência. Machos e fêmeas não diferiram quanto à riqueza de frutos consumidos (t = 0.083; DF = 32; p = 0.934), o que também não variou sazonalmente (H = 3.165; p = 0.367). A maior amplitude de nicho trófico ocorreu no verão, registrando-se duas vezes mais frutos na dieta do que no outono, estação com a menor amplitude. Tanto a porcentagem quanto a velocidade de germinação das sementes de Ficus cestrifolia e Psidium sp. aumentaram após a passagem pelo trato digestório do animal (a porcentagem de germinação aumentou mais de 40% e a velocidade foi até 7 vezes maior). Didelphis albiventris pode ser considerada uma espécie frugívora-onívora, uma vez que frutos representam um item importante na dieta, e contribui para a dispersão de grande quantidade de sementes endozoocóricas pequenas, aumentando tanto o percentual quanto a velocidade de germinação de algumas espécies.

Abstract Seed dispersal is a process that is fundamental to maintenance of forest ecosystems, enabling plants to successfully germinate in sites that are favorable to their growth, minimizing risks of competition, the action of pathogens and predation by herbivores. Intraspecific and seasonal variations in fruit consumption by Didelphis albiventris, and its contribution to dispersal and germination of endozoochorous seeds were analyzed in a Semideciduous seasonal forest. The study was conducted at Morro do Coco, which is a hilly area in the municipal district of Viamão, RS, Brazil, bordering the shore of Guaíba lake (30º16’15”S, 51º02’54”W), between June 2013 and May 2014, with a total sampling effort of 2992 trap-nights. A total of 18 individuals were captured and 24 fecal samples were collected. Fruits were identified in 96% of the samples, corresponding to 18 plant species, belonging to 10 families. The most common species were Ficus cestrifolia and Syagrus romanzoffiana, which occurred in 66% of the samples, followed by Banara parviflora and Cecropia pachystachya, both with a 25% rate of occurrence. There were no differences between the richness of fruit consumed by males and females (t = 0.083; DF = 32; p = 0.934) and there were no seasonal variations (H = 3.165; p = 0.367). The greatest breadth of dietary niche occurred during the summer, when twice as many fruit species were recorded in the diet than during the autumn, which was the season with the smallest breadth. Both germination percentage and germination velocity of Ficus cestrifolia and Psidium sp. seeds increased after passage through the animals’ digestive tracts (percentage germination increased more than 40% and velocity was up to 7 times highest). Didelphis albiventris can be considered a frugivorous-omnivorous species, since fruit are an important item of its diet, and it contributes to dispersal of a large quantity of small endozoochorous seeds, increasing both germination percentage and germination velocity of some species.