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

Abstract

RESUMO(Variação morfo-fisiológica em plantas sob distintos extremos ambientais em vegetação de restinga) Este trabalho é uma síntese das informações obtidas em mais de dez anos de pesquisas sobre variação morfofisiológica entre populações e dentre indivíduos de uma mesma população para seis espécies da restinga de Jacarepiá: os arbustos Alchornea triplinervia, Andira legalis, Clusia fluminensis e Myrsine parvifolia, a bromélia Aechmea maasii (anteriormente identificada como Aechmea bromeliifolia, que agora é como são denominadas plantas ocorrentes no Brasil central) e a palmeira geófita Allagoptera arenaria. Forma, porte e crescimento de indivíduos, anatomia foliar, fotoinibição da fotossíntese e uso de carbono, nitrogênio e água foram os principais parâmetros estudados. Com freqüência, a análise isolada da variação de um desses parâmetros não permite distinguir aclimatação de sintoma de injúria. Logo, os estudos aqui revisados apresentam uma abordagem que integra os diferentes parâmetros auto-ecológicos mencionados, assim como estes a parâmetros populacionais. Variação em caracteres morfológicos, anatômicos e fisiológicos foi detectada para a maioria destas espécies e, em geral, apontou para uma grande capacidade de aclimatação das mesmas a distintas circunstâncias ambientais. Tal capacidade de ajuste deve ter sido essencial para que várias destas espécies, na maioria oriundas de ambientes florestais, pudessem vir a colonizar um ambiente extremo como as restingas. Esta mesma capacidade é um elemento a mais a ser contabilizado como componente da grande biodiversidade existente no complexo vegetacional atlântico. Por fim, discutimos as implicações para conservação da biodiversidade da variação intra-específica encontrada ao nível populacional. Palavras-chave: aclimatação, anatomia foliar, crescimento clonal, fotoinibição, restinga, variação intra-específica. ABSTRACT(Plant morpho-physiological variation under distinct environmental extremes in restinga vegetation) This paper is a synthesis of over ten years of research on inter-and intra-population variation in morphophysiology of six plant species at the Jacarepiá restinga: the shrubs Alchornea triplinervia, Andira legalis, Clusia fluminensis and Myrsine parvifolia, the bromeliad Aechmea maasii (formerly identified as Aechmea bromeliifolia, now recognized as a species only found in Central Brazil) and the geophyte palm Allagoptera arenaria. Individual shape, stature and growth, leaf anatomy, photoinhibition, and carbon, nitrogen and water use were the main parameters studied. The isolated study of intra-specific variation in one or a few of the above-mentioned traits often does not allow a distinction between acclimation and stress symptoms. Thus, we used an approach that integrated morphology, anatomy, physiology and also population parameters. Variation in morphological, anatomical and physiological traits was found for the majority of these species, and often indicated great acclimation capacity to distinct environmental extremes. This acclimation capacity ma...

Pervasive migration across rainforest and sandy coastal plain Aechmea nudicaulis (Bromeliaceae) populations despite contrasting environmental conditions

“…Similarly, the nuclear data also seem to indicate that gene flow between forests and restingas has been maintained although pollen dispersal (Figures and ). These findings are in agreement with previous hypotheses that pre‐adapted or highly plastic rainforest species repeatedly colonized the restingas (Araujo, ; Scarano et al., ). In addition, the pervasive interhabitat gene flow uncovered here may help explain the very low level of endemism observed in these sandy communities (Scarano et al., ).…”

“…As in other sandy coastal plains, the environmental conditions found in the restinga impose a series of physiological stresses on plants. The sandy soil has low water‐retention capacity and low nutrient levels, severely impairing resource acquisition (Araujo, ; Rosado & Mattos, ; Scarano, Barros, Loh, de Mattos, & Wendt, ). Furthermore, restingas are open environments that expose plants to high solar irradiation and warmer temperatures than those found in the forest.…”

A revision of Aechmea subgenus Macrochordion (Bromeliaceae) based on phenetic analyses of morphological variation

“…Phenetic analyses, however, indicate that A. maasii is closely related to A. alba and A. lamarchei (Figs 1, 2). Aechmea maasii shows a great ecological plasticity and phenotypic variation in vegetative structures (Scarano et al. , 2002, 2009), but can be characterized by the flowers with yellow corollas and depressed ovate, truncate–apiculate and densely floccose floral bracts (Figs 8D, 10I, J).…”

No place for phylogeny in structuring a sandy coastal plain community

“…As stated before, experimental studies have show that even strong compe77on can fail to produce an overdispersed trait paXern, and in fact result in trait clustering (Mayfield and Levine, 2010;Burns and Strauss, 2012;BenneX et al, 2013). Intense compe77on for light also seems unlikely in an open community where excess light is usually the villain rather than a rare resource (Scarano et al, 2009;Rosado and E. A. d. MaXos, 2010). Finally, the fact that the frequency of plots with significantly overdispersed leaf area decreased at finer spa7al scales also contradicts that interpreta7on, since compe77on should be stronger (or captured more frequently) at smaller scales spa7al (Slingsby and Verboom, 2006;Cavender-Bares et al, 2006).…”

“…The lack of phylogene7c signal in these leaf traits may be an ar7fact of strong habitat filtering at larger geographic scales (Emerson and Gillespie, 2008;Vamosi et al, 2009). Most species inhabi7ng the sandy coastal plains come from adjacent forests (Scarano et al, 2009) and they likely represent a non-random sample of leaf func7onal traits. This hierarchical habitat-filtering process (Silvertown et al, 2006) may therefore dras7cally change the composi7on of the regional species pool and, and in turn, bias es7mates of phylogene7c signal.…”