RESUMOEm função de se analisar a produção, dinâmica e decomposição de serrapilheira em busca da sazonalidade do microclima em uma floresta tropical de transição Amazônia Cerrado, propõe-se estimar a produção de serrapilheira, por meio de caixas de coleta de 1 m 2 e o acúmulo de serrapilheira sobre o solo por meio de quadrantes de 25 x 25 cm, distribuídos aleatoriamente. Determinaram-se a constante de decaimento (K), o coeficiente de retorno de serrapilheira (K L ) e a constante de decomposição (K'). Com o emprego de bolsas de nylon preenchidas com folhas de espécies de relevância na floresta (Tovomita schomburgkki e Brosimium lactescens) estudou-se a decomposição de folhas e se monitaram os fatores ambientais por meio de equipamentos instalados em uma torre micrometeorológica. A produção de serrapilheira não só se apresentou de forma sazonal, com significativa influência da umidade relativa do ar e da precipitação, em uma floresta de transição, mas foi majoritariamente composta de folhas seguidas de galhos e miscelânea (flores e frutos). A decomposição de folhas em florestas tropicais foi acelerada em ambas as estações, seca-úmida e úmida-seca, sendo a velocidade de decomposição das folhas maior na estação úmida-seca.Palavras-chave: acúmulo de serrapilheira no solo, Amazônica, decomposição de folhas Seasonal dynamics of the litterfall production and decomposition in tropical transitional forest ABSTRACTThe objective of this study was to analyze the production, dynamics and litter decomposition as a function of the seasonality of the microclimate in a transitional tropical forest of Amazonia Cerrado. Estimate of litterfall was carried out with collection boxes of 1 m 2 and floor forest mass with quadrants of 25 x 25 cm distributed randomly. The decline constant (K), litter turnover rate (K L ) and litter decomposition rate (K') were determined by estimation of litterfall and forest floor litter mass. Leaf decomposition was studied by litter bags with leaves of species of relevance (Tovomita schomburgkki and Brosimium lactescens) in the forest. The analysis of the environmental factors was measured through micrometeorological equipments. The litterfall was seasonal in nature, with significant influence from relative air humidity and rainfall in a transitional forest. Litterfall was mainly composed of leaves, followed by twigs, and miscellany (flowers and fruits). The leaf decomposition in tropical forests was accelerated in seasons, dry-wet and wet-dry, being the leaf decomposition higher in the wet-dry season.

[1] This study analyzed how seasonal and interannual variations in climate alter litter dynamics, including production, decomposition, and accumulation. Monthly measurements of leaf, stem, and reproductive (flower plus fruit) litter and the forest floor litter mass were combined with a mass balance model to determine rates of litter decomposition for a semideciduous tropical forest located in the rain forest-savanna ecotone of the southern Amazon Basin for [2001][2002][2003][2004][2005][2006][2007]. Annual rates of litter production varied between 8 and 10.5 Mg ha À1 a À1 , and leaf litter production accounted for the majority ($70%) of the total litter production. Leaf litter production peaked at the end of the May-August dry season while stem litter production peaked during the wet season and reproductive litter production peaked during the dry-wet season transition. Forest floor litter mass ranged between 5 and 8 Mg ha À1 over the study period and generally declined as litter inputs declined. Litter decomposition rates were remarkably stable from year-toyear and varied between 10.8 and 12.4 Mg ha À1 a À1 . On average, rates of litter decomposition were highest during the dry-wet season transition. Overall, our results suggest that rainfall variability directly altered litter production dynamics and indirectly altered forest floor litter mass and decomposition kinetics through its effect on litter production. Future changes in seasonal and/or interannual rainfall patterns, whether in response to El Niño or to anthropogenic climate change, will likely have important consequences for the litter dynamics of Amazonian semideciduous forest.

[1] Measurements of soil CO 2 efflux, litter production, and the surface litter pool biomass were made over a 1 year period in a tropical transitional forest near Sinop, Mato Grosso, Brazil with the aim of quantifying the seasonal variation in soil respiration and litter decomposition and the annual contribution of litter decomposition to soil CO 2 efflux. Average annual soil CO 2 efflux (±95% confidence interval (CI)) was 7.91 ± 1.16 g C m À2 d À1 . Soil CO 2 efflux was highest during the November-February wet season (9.15 ± 0.90 g C m À2 d À1 ) and lowest during the May-September dry season (6.19 ± 1.40 g C m À2 d À1 ), and over 60% of the variation in seasonal soil CO 2 efflux was explained by seasonal variations in soil temperature and moisture. Mass balance estimates of mean (±95% CI) decomposition rates were statistically different between the wet and dry seasons (0.66 ± 0.08 and 1.65 ± 0.10 g C m À2 d À1 , respectively), and overall, decomposition of leaf litter comprised 16% of the average annual soil respiration. Leaf litter production was higher during the dry season, and mean (±95% CI) leaf litter fall (5.6 ± 1.7 Mg ha À1

RESUMO:As pesquisas realizadas a partir de recursos genéticos de espécies medicinais nativas somente serão aplicadas se o material genético estiver seguro quanto à sobrevivência e disponibilidade. O objetivo deste artigo foi realizar uma revisão bibliográfica adotando como critério a escolha de artigos publicados em conceituadas revistas nacionais e internacionais, que permitissem melhor entendimento dos aspectos etnobotânicos, ecológicos e químicos de importante planta medicinal e aromática: Siparuna guianensis Aublet. Como tem sido apontada como uma das espécies prioritárias de conservação para a região do cerrado brasileiro, os estudos da propagação devem ser incentivados para que este recurso genético esteja disponível às gerações futuras.Palavras-chave: etnofarmacologia, fitoquímica, propagação, cerrado, plantas medicinais ASTRACT: Siparuna guianensis Aublet ("negramina"): a review. Studies with genetic resources of native medicinal species will only be applied if their genetic material is safe regarding survival and availability. The aim of this study was to do a literature review adopting as criterion the choice of papers published in renowned national and international journals to allow better understanding on ethnobotanical, ecological and chemical aspects of an important medicinal and aromatic plant, Siparuna guianensis Aublet. Since the latter has been considered one of the major species for the conservation of Brazilian cerrado, studies on its propagation should be encouraged in order to make this genetic resource available to future generations. INTRODUÇÃOAs pesquisas realizadas a partir de recursos genéticos de espécies medicinais nativas somente serão aplicadas se o material genético estiver seguro quanto à sobrevivência e disponibilidade. Por isso, são necessários estudos que investiguem a melhor forma de propagação para que se desenvolva o cultivo e manejo (Albuquerque et al., 2003).O Brasil possui cinco áreas de grande abundância de plantas nativas, estando entre elas o bioma Cerrado, que está entre os 34 "hotspots", as mais ricas e mais ameaçadas reserv as da biodiversidade da Terra. Apenas 2,2% da área do cerrado encontra-se legalmente protegida e, somando-se ao problema, estima-se que 20% das espécies ameaçadas ou endêmicas não ocorram nas áreas legalmente protegidas (Klink & Machado, 2005). É preciso considerar que os recursos naturais oferecidos por este bioma, uma vez extintos, estarão indisponíveis às futuras gerações. Entre estes, podese considerar o recurso terapêutico oferecido pelas plantas medicinais (Guarim Neto & Morais, 2003).O objetivo deste artigo foi realizar revisão bibliográfica, adotando como critério a pesquisa documental a partir de artigos e livros publicados em conceituadas revistas nacionais e internacionais especializadas em plantas medicinais, que permitissem melhor entendimento dos aspectos etnobotânicos, ecológicos e químicos de importante REVISÃO Rev. Bras. Pl. Med., Botucatu, v.12, n.1, p.96-104, 2010.

The agriculture account is 92% of the global freshwater footprint, and 29% of this amount is used in animal husbandry to produce forage, to mix animal feed, for drinking of the animals and, at least, in the farm activities. In this trial we tested two diets whose production is characterized by different water consumption. Two homogeneous groups of milking cows were used to compare two different diets: standard feeding, with corn silage-based diet; and alternative feeding, with triticale silage-based diet. Both silages represented about 47% of diet composition. Diets were characterized by the same energy and protein content. Despite the lowest water consumption of the triticale silage group, no significant differences were observed between the groups on production level and on milk chemical composition.