Ecologists seek a general scheme to classify the diversity of plant responses to environmental factors into a few strategies (e.g. competitor—C, stress tolerant—S, ruderal—R), while plant physiologists seek a mechanistic scheme to explain such different responses (e.g. tolerance, escape, avoidance). So far, few attempts have been made to combine both perspectives into plant eco‐physiological strategies. Moreover, the relative contribution of different strategies to maintain both community structure and ecosystem functioning during drought has rarely been assessed. Thus, limiting our capacity to predict how extreme events caused by climate change will affect plant communities. Here, we present an integrated framework to identify plant eco‐physiological strategies and to estimate their contribution to community originality (diversity of trait combinations), dominance (species relative frequency) and ecosystem functioning (productivity and evapotranspiration). We applied this framework in a tropical montane grassland in Brazil (Campos de Altitude) and found three eco‐physiological strategies co‐occurring in this community (S‐tolerance/avoidance, CS‐escape/tolerance and CR‐escape/avoidance). While CS‐species contributed more to dominance and functionality, CR‐ and S‐species contributed more to originality. Therefore, all three strategies were important to support the grassland form and function. Synthesis. Plants exhibit different strategies, as well as different contributions to community and ecosystem attributes. We developed an integrated approach to both identify strategies and estimate their relative contribution. Thereby, as droughts intensify, we can better predict which plants are more likely to be lost and how their loss will impact the communities and ecosystem where they occur. This knowledge is necessary for specifying conservation priorities and for developing more efficient conservation practices.

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-(Leaf anatomy variation within and between three "restinga" populations of Erythroxylum ovalifolium Peyr. (Erythroxylaceae) in Southeast Brazil). Erythroxylum ovalifolium is a woody shrub widespread in the "restinga", i.e. the open scrub vegetation of the Brazilian coastal sandy plains. We examined leaf anatomy variation of this species both within populations and between populations of three "restingas" in the state of Rio de Janeiro. Sites were ca.100 km far from each other and differed in regard to rainfall and vegetation structure: a dry, open site; a wet, dense site and an intermediate one.Microhabitats within sites were: (i) exposed to full irradiance, outside vegetation islands; (ii) partially exposed to full irradiance, at the border of vegetation islands; (iii) shaded, inside vegetation islands. Leaf anatomy parameters were measured for five leaves collected in each of five plants per microhabitat, in each population; they were thickness of the leaf blade, of the palisade and spongy parenchyma, and of the adaxial and abaxial epidermis. Leaves from the dry, open site had narrower abaxial epidermis and a smaller contribution of spongy parenchyma to total leaf blade thickeness than the other two sites, which we attributed to water stress. Adaxial epidermis and leaf are thicker in more exposed microhabitats (i and ii, above), irrespective of site. We proposed that between-site anatomical variation in traits related to water stress, and within-site anatomical variation in traits related to light-use are indicative of ecological plasticity and might help explain the high abundance of E. ovalifolium in the studied populations and along the State of Rio de Janeiro coast.Key words -anatomic variation, Erythroxylum ovalifolium, mesophyll, sun-shade plants RESUMO -(Variação na anatomia foliar de Erythroxylum ovalifolium Peyr. (Erythroxylaceae) entre e dentro de três populações de restinga no Sudeste do Brasil). Erythroxylum ovalifolium é um arbusto lenhoso amplamente distribuído nas restingas, i.e., a vegetação arbustiva aberta das planícies arenosas costeiras do Brasil. Examinou-se a anatomia foliar desta espécie entre populações de três restingas do Estado do Rio de Janeiro, bem como entre três distintos microhabitats no interior de cada restinga. As localidades distavam ca.100 km entre si e diferiram quanto à precipitação e estrutura da vegetação: uma localidade seca e aberta; uma localidade úmida e densamente vegetada e uma localidade intermediária quanto a estes parâmetros. Os microhabitats foram: (i) exposto a radiância total, ocorrendo fora da ilha de vegetação; (ii) parcialmente exposto a radiância total, ocorrendo na borda da ilha de vegetação; (iii) sombreado, ocorrendo dentro da ilha de vegetação. Os parâmetros anatômicos foliares foram medidos para cinco folhas coletadas em cada um de cinco indivíduos por microhabitat, nas três localidades. Foram eles a espessura da lâmina foliar, dos parênquimas esponjoso e paliçádico, e das epidermes adaxial e abaxial. Folhas da localidade seca e aberta tiv...

Background and Aims The aroid vine Rhodospatha oblongata is characterized by a habitat change from terrestrial to canopy, relying on aerial roots at maturity to obtain water and nutrients from the forest soil. We hypothesize that morpho-physiological acclimation occurs in roots as they grow under atmospheric conditions. These changes would guarantee the whole plant survival of aroid vines in the new and potentially stressful habitat of the canopy. Methods Terrestrial and aerial roots were compared on a morpho-physiological basis. Root anatomy, water balance, water absorption capacity via fluorescent tracer, and photochemical activity via chlorophyll fluorescence were measured. Key Results While thin fasciculate roots occur on terrestrial crawling individuals, two clearly distinct aerial roots (anchor and feeder) are produced on canopy individuals, which are both adhered to the host trunk. The color of both aerial roots change during development from red and brownish to striped and green at maturity. Color changes are induced by the replacement of epidermis, exodermis, and outer cortex by an inner layer of lignified cork on the root region exposed to the atmosphere. In the root region that is in contact with the host, covering substitutions do not occur and both exodermis and lignified cork, along with several epidermal hairs, appear. Water retention capacity was higher in green roots than in other root types. Rehydration capacity via water absorption by hairs of aerial roots was confirmed by fluorescence. Chlorophyll fluorescence data indicated low levels of photosynthetic capacity in both root types. Conclusions Plants should evolve strategies to survive stress situations. The transition from soil to canopy imposes abiotic changes and potentially stressful situations to R. oblongata. We conclude that the morpho-physiological changes observed represent an important strategy that permits the maintenance of aroid roots and the survival of R. oblongata in the canopy.

-(Photosynthetic properties of three Brazilian seaweeds). Photosynthetic performance of distinct marine macroalgae, Ulva fasciata Delile (green alga), Lobophora variegata (J. V. Lamouroux) Womersley ex E. C. Oliveira (brown alga), and Plocamium brasiliensis (Greville) M. A. Howe & W. R. Taylor (red alga), were compared using a pulse amplitude-modulated fl uorometer. The maximum quantum yield (F v /F m ) ranged from 0.80 to 0.51, and the lowest value was found in P. brasiliensis. Under 400 μmol photons m -2 s -1 irradiance, the highest value of photochemical quenching (qP = 0.92 ± 0.13) was observed for U. fasciata. The red alga P. brasiliensis dissipated high amounts of excitation energy (qN = 0.56 ± 0.09), resulting in relatively low values for the effective quantum yield of PS-II (0.23 ± 0.04), as well as for the relative electron transport rate (3.3 ± 0.7). The high photosynthetic potential found for U. fasciata partially explains the species ability for rapid growth and high productivity. , o maior valor de dissipação fotoquímica (qP = 0,92 ± 0,13) foi observado para U. fasciata. A alga vermelha P. brasiliensis dissipou elevada quantidade de energia de excitação (qN = 0,56 ± 0,09), resultando em valores baixos de potencial fotoquímico efetivo do PS II (0,23 ± 0,04), e também de taxa relativa de transporte de elétrons (3,3 ± 0,7). O elevado potencial fotossintético encontrado para U. fasciata explica, parcialmente, a capacidade da espécie de crescimento rápido e de alta produtividade.Palavras-chave -fl uorescência da clorofi la, Lobophora variegata, Plocamium brasiliensis, Ulva fasciata 1.