RESUMO -(Produção, acúmulo e decomposição da serapilheira em uma restinga da Ilha do Mel, Paranaguá, PR, Brasil). Em uma formação de restinga na Ilha do Mel, Paranaguá-PR, foram avaliadas, mensalmente, a serapilheira produzida e a acumulada, em quadrados de 0,25 m 2 , durante um ano (julho/1996-junho/1997). A decomposição, mensal e anual, foi estimada, indiretamente, pela razão entre serapilheira produzida e acumulada. A produção anual de serapilheira de 5,1 t.ha -1 encontra-se no limite inferior aos obtidos em outras florestas tropicais, e decorre, provavelmente, do solo arenoso e pobre em nutrientes. A produção e a decomposição foram sazonais, mais intensa durante o período mais quente e chuvoso, estando relacionadas, principalmente, à temperatura. O pequeno acúmulo de serapilheira (5,5t.ha -1 .ano -1 ), e a ausência de variações mensais significativas neste compartimento denotam o sincronismo entre estes processos, que, aliado a taxa de decomposição anual relativamente baixa (k L = 0,92), representa grande valor adaptativo para o ecossistema, pois, pode minimizar as perdas por lixiviação e permitir um melhor aproveitamento dos nutrientes e água disponíveis momentaneamente. Tais mecanismos, bem como o caráter perenifólio das espécies, escleromorfia, e uma rede de raízes superficiais, possibilitam o desenvolvimento da comunidade vegetal sob as condições oligotróficas do solo. Estes, além do clima, parecem exercer uma forte influencia na determinação dos padrões de produção e decomposição da serapilheira.Palavras-chave : produção de serapilheira, serapilheira acumulada, decomposição, restinga, sazonalidade ABSTRACT -(Litter fall, accumulation and decomposition in a restinga at Ilha do Mel, Paranaguá, Paraná, Brazil). Litter fall and accumulation in restinga vegetation were evaluated monthly in 0.25 m 2 quadrats from July 1996 to June 1997 at Ilha do Mel, Paranaguá, Paraná, Brazil. Monthly and annual decomposition were also estimated indirectly by the ratio produced:accumulated litter. Annual litter fall (5.1 t.ha -1 ) was low when compared to results found in other tropical forests, probably due to the sandy, nutrient-poor soils. Production and decomposition were seasonal, that is, more intense during the warm, rainy months, and are mainly related to temperature. Monthly changes in litter accumulation were small, as was overall litter accumulation (5.5 t.ha -1 .year -1 ). The synchronism among these processes and the relatively low annual decomposition rate (k = 0.92) represent adaptations for the ecosystem since they minimize loss from leaching, and allow better use of both nutrients and water at short intervals. Such mechanisms, coupled with the non-deciduous nature of the species, sclerosis, and a network of superficial roots, facilitate plant community development in oligotrophic conditions. These conditions, as well as climate, appear to exercise strong influence in determining patterns of litter production and decomposition.

RESUMO -(Germinação de Ternstroemia brasiliensis Cambess. (Pentaphylacaceae) de Floresta de Restinga). A partir de ensaios de germinação no campo e no laboratório, este trabalho visa contribuir para o conhecimento da ecologia da regeneração de Ternstroemia brasiliensis Cambess. em Floresta de Restinga. As sementes são dispersas com teores de água relativamente altos e apresentam baixa tolerância ao armazenamento, podendo ser consideradas recalcitrantes. A germinabilidade é elevada, indiferente à luz e não é afetada pela presença do arilo. A ausência de dormência e a pequena resposta ao vermelho extremo devem permitir pronta germinação no sub-bosque, não constituindo banco de sementes no solo da Restinga. As temperaturas de 25 ºC e 30 ºC podem ser consideradas ótimas para a germinação de T. brasiliensis. A luz pode afetar parâmetros da resposta das sementes à temperatura. A aplicação do modelo de graus-dia parece ser um instrumento válido para se estudar a dependência da temperatura da germinação dessa espécie. As características germinativas de T. brasiliensis são semelhantes às de espécies não-pioneiras e ajudam a explicar a distribuição da espécie. Luz e temperatura não devem ser limitantes para sua germinação no ambiente natural da Restinga, a qual pode ser influenciada principalmente pelo nível de água no solo. Palavras-chave:Ecofisiologia, graus-dia, luz, sementes, temperatura ABSTRACT -(Germination of Ternstroemia brasiliensis Cambess. (Pentaphylacaceae) from a Restinga Forest). The main purpose of this work was to study the germination of Ternstroemia brasiliensis seeds both in laboratory and field conditions in order to contribute to understanding the regeneration ecology of the species. The seeds were dispersed with relatively high moisture content and exhibit a recalcitrant storage behaviour because of their sensitivity to dehydration and to dry storage. The germinability is relatively high and is not affected either by light or aril presence. The absence of the dormancy and the low sensitivity to far red light can enable to seeds to promptly germinate under Restinga forest canopy, not forming a soil seed bank. The constant temperatures of 25 ºC and 30 ºC were considered optimum for germination of T. brasiliensis seeds. Temperature germination parameters can be affected by light conditions. The thermal-time model can be a suitable tool for investigating the temperature dependence on the seed germination of T. brasiliensis. The germination characteristics de T. brasiliensis are typical of non pioneer species, and help to explain the distribution of the species. Germination of T. brasiliensis seeds in Restinga environment may be not limited by light and temperature; otherwise the soil moisture content can affect the seed germination.Key words: ecophysiology, light, seeds, temperature, thermal-time IntroduçãoEm florestas tropicais de terras baixas a regeneração da maioria das árvores dá-se por intermédio de sementes. Dessa forma, o conhecimento do efeito de diferentes fatores ambientais sobre a germinação...

The germination response of Ocotea pulchella (Nees) Mez seeds to light, temperature, water level and pulp presence is introduced. The laboratory assays were carried out in germination chambers and thermal-gradient apparatus, whereas the field assays were performed in environments with distinct light, temperature and soil moisture conditions within a permanent parcel of Restinga forest of the Parque Estadual da Ilha do Cardoso, Cananéia, São Paulo. The seeds do not exhibit dormancy, they are non photoblastic, and a loss of viability in dry stored seeds can be related to a decrease in water content of the seed. The presence of the pulp and the flooded substratum influenced negatively the germination of O. pulchella seeds tested in the laboratory. Otherwise, light and temperature probably are not limiting factors of the germination of O. pulchella seeds in the natural environment of Restinga. The optimum temperature range for germination of Ocotea pulchella seeds was 20 to 32 °C, the minimum or base temperature estimated was 11 °C and the maximum ranged between 33 and 42 °C. The isotherms exhibited a sigmoidal pattern well described by the Weibull model in the sub-optimal temperature range. The germinability of O. pulchella seeds in the understorey, both in wet and dry soil, was higher than in gaps. Germination was not affected by fluctuations in soil moisture content in the understorey environment, whereas in gaps, germination was higher in wet soils. Thus, the germination of this species involves the interaction of two or more factors and it cannot be explained by a single factor. Keywords

The present study approached some aspects of the nutrient cycling in a "Restinga" formation, at Ilha do Mel, Paranaguá, Paraná, Brazil. The monthly and annual litter production and accumulation, as well as nutrient contents; the nutrient contents in fresh leaves and in the litterfall of the most important species of community; the decomposition and the nutrient renovation rates of accumulated litterfall; the foliar litterfall decomposition and the nutrient mineralization were studied. The annual litter production (5080,6 kg. ha -1 ), as well as other "Restinga" formation, is inferior than those of the majority of the tropical forests, probably due to the edaphic conditions. The litter production, caracterized by foliar fraction, was more intense in high temperature and precipitation period. The annual medium concentrations of nutrients in the produced foliar litterfall are whithin the variations found in tropical forests, highligthing the low concentrations of N, Cu, Mn and Fe, while Ca, P and B presented relatively high discharges. Ternstroemia brasilienses, Tapirira guianensis, Guapira opposita, Ilex theezans and Clusia criuva represented 60,3% of the total of leaves deposited during the year. The medium contents of Ca, N, P and Mg, obtained in fresh leaves of the four analyzed species (Guapira opposita, Ocotea pulchella, Tapirira guianensis, Ternstroemia brasiliensis), showed higher than those described for other forests on sandy soils. The results suggest an strong influence of the salt spray in the input of the nutrients to the ecossystem, mainly Ca, Mg and B. A great litter accumulation (5541,9 Kg. ha -1 ano -1 ) was not observed, in despite of the calculated decomposition coefficient values are considered low for tropical forests. The slow decomposition observed in the restinga ecosystems is probably due to the high degree of vegetable scleromorphy, which is allied to the edaphic conditions. This characteristic, as well as the synchrony observed between the litter production and decomposition, are efficient adaptations for its maintenance of the ecossystem, because enables a smaller loss of nutrient through leaching, whereas those communities are established in a moist climate, and sandy soils areas, poor chemically and very leached. The elements S, Ca and Cu presented the largest residency time in the accumulated litterfall, being restrained on the compartiment. The elements that presented the largest remaining amount in the decomposition bags, after one year of studies, were N and Fe, because the immobilization in the tissues of the decompositor organisms and low mobility, respectively. The elements K, S and Cu had smaller remaining amounts, denoting their susceptibility to leaching. The characteristics observed for the litter production and decomposition promote an efficient nutrient cycling, showing that the studied community is well adapted to the oligothrophy soils.

Neste trabalho, avaliou-se os efeitos de fatores ambientais na sobrevivência e crescimento inicial de Ocotea pulchella (Nees) Mez numa floresta de restinga. Os ensaios consistiram do plantio de mudas classificadas em dois grupos de idade (plântulas e juvenis) em diferentes áreas selecionadas quanto à cobertura vegetal (clareiras ou sub-bosque) e umidade do solo (secos e úmidos). As plantas de ambas as idades apresentaram a maior taxa de mortalidade no sub-bosque úmido, onde se observou os valores mais baixos de luz fotossinteticamente ativa e fertilidade do solo. A sobrevivência de plântulas correlacionou-se positivamente ao crescimento, que por sua vez, foi favorecido em clareiras, sugerindo uma dependência da espécie em relação a ambientes mais iluminados, embora essa possa ocupar o sub-bosque em fisionomias mais abertas como as restingas. Em juvenis, a sobrevivência foi relacionada principalmente aos fatores edáficos; o crescimento em altura foi muito baixo, não sendo constatado incremento significativo de área foliar nem de matéria seca em nenhum dos ambientes, o que pode estar relacionado ao caráter oligotrófico do solo. Os juvenis em sub-bosque de solo úmido apresentaram ao final do experimento os menores valores de altura, área foliar, razão de área foliar, razão de massa foliar e taxa de assimilação líquida, sugerindo que baixas irradiâncias associadas a solos saturados e quimicamente pobres podem restringir o recrutamento da espécie no local estudado. Todavia, o comportamento de certa forma generalista para as condições de luz e umidade do solo, indica uma alta capacidade de O. pulchella em colonizar distintos micro-ambientes da restinga, onde se observa uma grande variação espaço-temporal de fatores ambientais.

ABSTRACT(Eff ect of fl ooding on survival and initial growth of Ocotea pulchella (Nees) Mez. seedlings in semi-controlled light conditions). Taking into account the occurrence of Ocotea pulchella in areas subjected to periodic fl ooding, this work aimed to evaluate the survival and initial development of Ocotea pulchella seedlings (2 months old) and juveniles (9 months old) in response to waterlogging under diff erent light regimes by varying both light quantity and light quality, in order to test for possible fl ood tolerance of the species as aff ected by light conditions. Th ree levels of soil moisture (fi eld capacity, mean fl ooding -only for seedlings -and full fl ooding) and four light treatments (full sun, neutral shade, far red enriched shading and neutral plus far red) were tested. Th e survival of seedlings and juveniles during one year was relatively high, whereas growth was negatively aff ected by full sun and fl ooding. Seedling growth was inhibited by soil waterlogging whatever the light condition, whereas plant growth at fi eld capacity and mean fl ooding was similar. Flooding also inhibited the growth of juveniles, and that response was practically not aff ected by the light regimes. Th e results suggest that Ocotea pulchella seedlings can survive in the understory, even in areas subject to fl ooding, forming a slow-growth seedling bank. Th e species seems to tolerate relatively long-term soil waterlogging when kept out of direct sunlight. Otherwise, responses of waterlogged plants to shading seem to be aff ected by irradiance and light quality.

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