The clonal tank‐bromeliad Aechmea bromeliifolia (Rudge) Baker was found in four different habitats in a restinga (vegetation mosaic on sandy coastal plains), of south‐eastern Brazil. These habitats (swamp forest, dry forest, dry shrubland and herbaceous marsh) lie within a few hundred metres of each other along a gradient extending inland from the coast, and differ markedly in terms of light and flood regime. We compared ramet morphology, leaf anatomy and physiology, and population parameters to examine the amplitude of trait variation of this widespread species in the studied restinga. This integrated approach allowed us to examine which variation conferred acclimation and which was merely a stress symptom. A. bromeliifolia showed site‐specific differences in abundance, distribution, rosette size and shape, leaf anatomical arrangement and photochemical efficiency (potential quantum yield; Fv/Fm) during the day. Most of the variation found seemed to be related to the interaction of light and flooding. The lowest number and size of ramets at the exposed, dry shrubland was matched by a marked leaf photoinhibition, which suggested poor acclimation to local levels of light intensity and limited water supply. In the other habitats, the morpho‐physiological parameters measured suggested adequate foraging behaviour and site acclimation. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society, 2002, 140, 391‐401.

RESUMO O trabalho propõe a utilização dos caracteres anatômicos da madeira na interpretação da estrutura da comunidade arbórea da Reserva Biológica de Poço das Antas, RJ, Brasil (22º30' e 22º33'S e 42º15' e 42º19'W). Foram analisadas 26 espécies de 14 famílias, totalizando 72 espécimens. A alta incidência de características anatômicas comuns - camadas de crescimento distintas, porosidade difusa, placas de perfuração simples, fibras de paredes delgadas a espessas, raios com freqüência de 4 a 12/mm', com 1-3 células de largura, - foi corroborada pelas análises estatísticas, o que sugere a ocorrência de um padrão anatômico. Os resultados descritos se enquadram nas tendências ecológicas para espécies de planícies tropicais, que se caracterizam por uma menor freqüência de elementos de vaso mais largos e com placas de perfuração simples. Tais caracteres propiciam o transporte de grandes volumes de água por unidade de tempo e área transversal da madeira.

Studies on phenols have gained attention owing to their abundance in plants and their effects on plant development. Phenols from forage grasses may exert phytotoxicity on legume crops in intercropping systems. We aimed to identify morpho-anatomical variations in Calopogonium mucunoides Desv. roots treated with phenolic compounds. Seeds of C. mucunoides were treated with (1) distilled water (control), (2) trans-cinnamic acid, (3) a mixture of the flavonoids quercetin, rutin, kaempferol and kaempferol-3-α-rhamnoside, or (4) a combination of the flavonoid mixture and trans-cinnamic acid. After 10 days of treatment, the roots were measured, described and processed according to standard techniques in plant anatomy. In general, non-control individuals showed plant lengths decreased by 40–45%, root-tip necrosis and intense lateral root ramification. Seeds germinated in cinnamic acid presented xylem poles with a greater number of cells and a greater emission of lateral roots. In the seeds treated with flavonoids, cell division was observed in the endodermis and the pericycle, and xylem fibres went through differentiation. The combination of cinnamic acid and flavonoids led to the premature formation of fibres by the phloem. The treatments with flavonoids or cinnamic acid alone were significantly greater in root diameter (868.61 µm and 810.35 µm, respectively) than was the application of both (714.98 µm) or the control (533.76 µm). The results suggest that cinnamic acid and the tested flavonoids negatively affect the development and the root structure of C. mucunoides.

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