Calophyllum brasiliense Camb. (Clusiaceae) is a tree of swampy areas of the coastal ''Restinga'' in southeastern Brazil (a coastal sand-plain scrub and forest formation). To elucidate possible adaptive strategies that enable this species to occupy areas subjected to seasonal or perennial waterlogging, growth characters such as shoot height, biomass production, leaf expansion, new leaf development, stem diameter, carbon dioxide assimilation rate, stomatal conductance, chlorophyll concentration and fluorescence were studied in controls and plants flooded for up to 150 days. Although flooded plants kept incorporating carbon all through the experiment, their assimilation rate and growth rate were lower than control, non-flooded plants. Injuries such as leaf senescence and abscision were not observed but some flooded plants showed signs of leaf chlorosis. In view of its capacity to maintain carbon assimilation and growth during the treatment, C. brasiliense can be classified as flood-tolerant tree. Flooding induced hypertrophy of lenticels, increased stem diameter and development of adventitious roots. These characteristics of C. brasiliense are most probably responsible for its survival and success in naturally seasonally flooded areas, inhospitable environments for most tree species. Reduction in total chlorophyll concentration was probably the main cause of reduced carbon dioxide assimilation rate. Based on the results we recommend C. brasiliense for rehabilitation of native vegetation in flood-prone areas.

In mature and young leaves of sunflower (Helianthus annuus L. cv. Catissol-01) plants grown in the greenhouse, photosynthetic rate, stomatal conductance, and transpiration rate declined during water stress independently of leaf age and recovered after 24-h rehydration. The intercellular CO 2 concentration, chlorophyll (Chl) content, and photochemical activity were not affected by water stress. However, non-photochemical quenching increased in mature stressed leaves. Rehydration recovered the levels of non-photochemical quenching and increased the F v /F m in young leaves. Drought did not alter the total Chl content. However, the accumulation of proline under drought was dependent on leaf age: higher content of proline was found in young leaves. After 24 h of rehydration the content of proline returned to the same contents as in control plants.Additional key words: chlorophyll; drought; intercellular CO 2 concentration; leaf water potential; non-photochemical quenching; photochemical activity; rehydration; stomatal conductance to water vapour; transpiration rate. ---The leaf water status and carbon uptake is under stomata control and stomata closure is one of the earliest responses to drought, resulting in protection of the plants against harmful dehydration but also inevitably results in reduction of CO 2 uptake for photosynthesis. The stomata control is important only under mild stress (Cornic 2000). However, metabolic inhibition of photosynthesis also takes place at mild water stress (Tezara et al. 1999) and it becomes more important as the water stress intensifies. Most of the studies in this area were done on mature leaves and the few available data comparing the effects of water stress on mature and young leaves indicate that the photosynthetic responses to water stress are strongly dependent on leaf age (David et al. 1998). In addition, there are indications that water stress accelerates leaf senescence (Olsson 1995).The accumulation of osmolyte compounds in the cells as a result of water stress is often associated with a possible mechanism to tolerate the harmful effect of water shortage. The contribution of sugars as an osmotic solute in expanded and partly expanded sunflower leaves was studied by Jones and Turner (1980). They found that contents of sugars did not change in fully expanded leaves. In opposition, the contents of soluble sugars in partly expanded leaves were reduced. In addition to sugars, some plants also accumulate other low molecular mass compounds, such as proline (Gzik 1996, Bajji et al. 2001. These osmolyte accumulations in plant cells might contribute, via lowering the cell osmotic potential, to maintaining several physiological processes, such as photosynthesis, stomatal conductance, and leaf expansion even under stressed conditions. The present experiment was designed to study the responses of photosynthesis to water stress in fully expanded and expanding leaves of sunflower plants. Additionally, the change in proline content and the ability of plants to recover from the water stres...

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A trombose é reconhecidamente uma doença de caráter multifatorial. Sua ocorrência está intimamente relacionada à presença de fatores genéticos e adquiridos que concorrem isoladamente ou em associação para o seu desencadeamento. No entanto, a frequência dos fatores genéticos pode variar de acordo com a origem étnica e com outros aspectos epidemiológicos dos grupos de indivíduos e populações estudadas. No Brasil, dados referentes a indivíduos brasileiros e em especial do estado de Minas Gerais são escassos. O objetivo do presente estudo foi investigar a frequência das mutações fator V Leiden e G20210A no gene protrombina em 1.103 indivíduos com suspeita clínica de trombofilia, empregando a técnica da reação em cadeia da polimerase seguida de restrição enzimática (PCR-RFLP). Os dados foram analisados usando-se o programa Epi Info versão 6.04. A amostra consistiu de 76,16% mulheres e 23,84% homens, com média de idade de 43,06± 14,65. A mutação fator V Leiden foi observada em heterozigose em 7,52% dos indivíduos e em 0,36% em homozigose. A mutação G20210A no gene da protrombina apresentou-se em heterozigose em 5,90% dos indivíduos e em homozigose em 0,18%. O presente trabalho mostra a importância dos testes genéticos conforme o perfil da população analisada, ressaltando informações epidemiológicas da população brasileira e benefícios clínicos.

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