Ecophysiology of selected tree species in different plant communities at the periphery of the Atlantic Forest of SE Brazil I. Performance of three different species of Clusia in an array of plant communities

Abstract

Three species of Clusia, namely two CAMspecies (C. hilariana Schlecht. and C. fluminensis Planch. et Triana) and a C 3 -species (C. parviflora Saldanha et Engl.) were studied in different plant communities at the periphery of the Atlantic Forest in the state of Rio de Janeiro, Brazil. The sites chosen were an inselberg (C. parviflora), a range of wet restinga -dry restinga -semideciduous dry forest (C. fluminensis), and a gradient from the sea shore inland with a first sand dune beach ridge -a dry forest -a second beach ridge (C. hilariana). Analyses comprised C and N contents, soluble carbohydrates, soluble nonprotein N compounds and carbon isotope ratios (δ 13 C) in leaves, roots, phloem and wood. Photosynthetic performance was assessed by chlorophyll fluorescence with measurements of instant photosynthetic yield as well as light dependence and potential quantum-use efficiency of photosystem II.The data allow, first, to discuss differences between the ecophysiological performance of C 3 -and CAM-species of Clusia. The C 3 -species, C. parvifolia, had an overall weaker performance than the two CAM-species, where, however, the effects of mode of photosynthesis may have been overlaid by site conditions. Second, it was studied whether ecophysiological performance relates to patterns of local abundance, which was confirmed by showing that the dominant Clusia species of the restingas, C. hilariana, showed the strongest performance overall.Finally, it was studied whether the ecophysiological performance varied in response to site-dependent gradients of environmental water relations, which was confirmed for functions such as photosynthetic capacity, photoinhibition and solute accumulation of C. hilariana and C. fluminensis in relation to moisture of sites.

Plant morpho-physiological variation under distinct environmental extremes in restinga vegetation

“…The modern techniques available for in situ measurements of photosynthesis and photoinhibition by portable high-precision equipment (see review in Schreiber et al 1995) have allowed rapid quantitative and qualitative advances in ecophysiological knowledge about plants in the restingas and other vegetation types adjacent to the Atlantic rainforest (see review in Scarano et al 2005a). At our study site, a number of studies have been conducted on plant chlorophyll a fluorescence, which is ultimately indicative of plant vigour since it allows assessment of parameters such as photoinhibition and electron transport rate (for review see Demmig-Adams & Adams 2006).…”

Biologia reprodutiva de Jacquinia armillaris (Primulaceae): uma espécie endêmica das restingas Brasileiras

“…Faria et al (2006) descreve a polinização nos ambientes de restinga como limitada por rigores intrínsecos desse ecossistema, o que gera irregularidades na taxa de produção (Scarano 2002;Scarano et al 2005;Faria et al 2006). No caso de J. armillaris, cujas populações são polinizadas por besouros, que promovem limitado fluxo gênico (Young 1986), os eventos de baixa produção de frutos podem se tornar mais comuns caso o quadro de fragmentação amplie a distância entre remanescentes cada vez menores (Fahrig 2003;Hobbs & Yates 2003).…”

Aquatic macrophytes drive sediment stoichiometry and the suspended particulate organic carbon composition of a tropical coastal lagoon

“…So, it may have some implications for the structure of Cabiúnas lagoon pelagic community, since we found POC composition to be primarily from macrophyte origin, which is also in agreement with recent decomposition experiments (Bianchini Jr. et al, 2006). The great importance of CAM and C4 terrestrial plants for DOC composition can be explained by the fact that restinga vegetation is dominated by plants with these metabolic pathways, particularly the CAM-species Clusia hilariana Schltdl., due to the their high growth performance in areas where water is scarce (Henriques et al, 1986;Araujo et al, 1998;Scarano et al, 2005). The soil of restinga is composed by sands, and the main source of OM is vegetation litter, especially from C. hilariana.…”