The main goal of this paper was the study of the useful plants sold in the open-air fairs of Petrópolis and Nova Friburgo, Rio de Janeiro, Brazil. Data collection was obtained through participant observation, semi structured interviews and free listing with four herbalist informants. From the interviews, 115 species (belonging to 49 families) were recorded: 94 for medicinal purposes, 12 with religious application, and 9 for ornamental purposes. Thirty percent of the species were native, and 72% herbaceous. The most representative families were Asteraceae (26 species) and Lamiaceae (10 species). The medicinal species related to diseases of the respiratory system were more common during the winter and autumn. "Espinheira-santa" (Clarisia cf. ilicifolia) had the highest Relative Importance (1.8) and collocation in all seasons using the Preference Ranking, although its effectiveness or toxicity levels have not been established. The importance of the study is to gather knowledge from local herbalists about commercialized species in open-air fairs and popular markets in the Rio de Janeiro State, which represent valuable resources for bioprospection. O principal objetivo desse trabalho foi estudar as plantas úteis comercializadas em feiras livres em Petrópolis e Nova Friburgo, Rio de Janeiro, Brasil. Os dados foram coletados utilizando as técnicas de observação participante, entrevistas semi-estruturadas e listagem livre com quatro comerciantes de plantas medicinais. A partir dessas entrevistas, 115 espécies (pertencentes a 49 famílias) foram relacionadas: 94 com uso medicinal, 12 com uso religioso e 9 com uso ornamental. Trinta por cento das espécies são nativas e 72% possuem hábito herbáceo. As famílias mais representativas foram Asteraceae (26 espécies) e Lamiaceae (10 espécies). As espécies medicinais indicadas para o tratamento de doenças do sistema respiratório foram mais freqüentes durante o outono e inverno. A espécie denominada como Espinheira-santa (Clarisia cf. ilicifolia) obteve o valor mais alto de Importância Relativa (1,8) e a mais alta colocação em todas as estações do ano utilizando o cálculo Preference Ranking, embora seus níveis de eficiência e toxidez não tenham sido ainda estabelecidos. O estudo se mostrou relevante, pois visa reunir o conhecimento dos informantes sobre as espécies que comercializam em feiras livres e mercados populares no estado do Rio de Janeiro, que representa uma valiosa fonte para a bioprospecção

Setaria viridis is being promoted as a model C₄ photosynthetic plant because it has a small genome (~515 Mb), a short life cycle (~60 d) and it can be transformed. Unlike other C₄ grasses such as maize, however, there is very little information about how C₄ leaf anatomy (Kranz anatomy) develops in S. viridis. As a foundation for future developmental genetic studies, we provide an anatomical and ultrastructural framework of early shoot development in S. viridis, focusing on the initiation of Kranz anatomy in seed leaves. Setaria viridis seeds were germinated and divided into five stages covering development from the dry seed (stage S0) to 36 h after germination (stage S4). Material at each of these stages was examined using conventional light, scanning and transmission electron microscopy. Dry seeds contained three embryonic leaf primordia at different developmental stages (plastochron 1–3 primordia). The oldest (P3) leaf primordium possessed several procambial centres whereas P2 displayed only ground meristem. At the tip of P3 primordia at stage S4, C₄ leaf anatomy typical of the malate dehydrogenase-dependent nicotinamide dinucleotide phosphate (NADP-ME) subtype was evident in that vascular bundles lacked a mestome layer and were surrounded by a single layer of bundle sheath cells that contained large, centrifugally located chloroplasts. Two to three mesophyll cells separated adjacent vascular bundles and one mesophyll cell layer on each of the abaxial and adaxial sides delimited vascular bundles from the epidermis. The morphological trajectory reported here provides a foundation for studies of gene regulation during early leaf development in S. viridis and a framework for comparative analyses with other C₄ grasses.

This paper originates from a presentation at the IIIrd International Congress on Crassulacean Acid Metabolism, Cape Tribulation, Queensland, Australia, August 2001. We investigated preference for nitrogen source and the influence of ammonium nitrate on leaf pigment content, crassulacean acid metabolism (CAM) activity, and the efficiency of PSII in Neoregelia cruenta (R.Graham) L.B. Smith, a CAM bromeliad of major ecological importance to restinga (coastal sand ridge plains) environments. Plants showed a preference for ammonium over nitrate in a 24-h experiment where plants were exposed to 15NH4NO3 or NH415NO3. Mature individuals of N. cruenta were exposed to 95 and 20% full sunlight, and treated with 5 mm NH4NO3 or tap water only. After 4 months under the different treatments we found that nitrogen uptake and carotenoid content were independent of light exposure. Total chlorophyll decreased under nitrogen limitation and high light. Net titratable acid accumulation was not influenced by light or nitrogen regimes. Plants under low light showed consistently high photochemical efficiency of PSII ( F v/ F m) throughout the day. In contrast, plants under high light and nitrogen limitation showed a significant decline in F v/ F m around midday, which recovered by the end of the light period. This decline in F v/ F m was attributed to increased non-photochemical quenching. Our findings that plants under high light and with high nitrogen behave similarly to shade plants were unexpected. They suggest that the high light, high nitrogen leaves used a greater portion of the light absorbed in PSII antennae for photochemistry than the high light, low nitrogen plants. High nitrogen content in the leaves of N. cruenta appears to protect this CAM bromeliad against photoinhibition.

Sun and shade plants are often discriminated by a number of sun- and shade-type anatomies. Nonetheless, we propose that among tank-bromeliads, changes in rosette architecture satisfy the requirements for coping with contrasting light levels. The tank-bromeliad Neoregelia cruenta naturally colonises sub-habitats ranging from full exposure to direct sunlight, to shaded environments in sand ridge plains. We quantified anatomical and morphological traits of leaves and rosettes of N. cruenta grown under sun and shade conditions. Cells with undulated lateral walls within the water parenchyma are for the first time described for the family. Under high light, leaf blades were wider, shorter, and yellowish. The rosette diameter of sun plants was less than half that of shade plants. Sun leaves overlapped with neighbouring leaves for most of their length, forming a cylindrical rosette where water accumulates. Shade leaves only overlapped in the centre of the rosette. Most anatomical traits were similar under both growth conditions. Stomata were absent from the base of sun leaves, which is probably explained by limited gas exchange at the base of the tight sun-type rosette. Data suggest that the ability of N. cruenta to acclimate to sun and shade is better explained by changes in rosette architecture than by leaf anatomy.