Abstract We investigated whether essential oil and aqueous and ethanolic extracts from M. vittoriana leaves have phytotoxic effects on the germination and initial development, and cytogenotoxic ...effects on the cell cycle, of model plants. The essential oil and extracts of M. vittoriana were characterized and used as treatments in phytotoxicity and cytotoxicity tests. The results indicated a reduction in germinative parameters and plant growth, with the higher concentrations of extracts and essential oil having the most evident effects. The cell cycle was also affected with a reduction of the mitotic index and the presence of chromosomal and nuclear alterations. All treatments showed clastogenic and aneugenic modes of action. The results can be associated with the synergistic effects of metabolites found in the extracts and essential oil, mainly the presence of the sesquiterpene germacrene D in the essential oil and of catechins, saponins, and tannins in the extracts. These substances inhibit plant germination and growth, confirming the phytotoxic effects of M. vittoriana in plant models, which should now be tested under field conditions.
Myrsine
, a genus in the family Primulaceae, includes closely related species whose taxonomic identification is difficult. Morphological analysis of pollen grains has provided key information for the ...classification of Primulaceae, helping clarify the taxonomy of several genera, subgenera, and species. However, a detailed study of pollen morphology in
Myrsine
was still lacking. Therefore, in this study, we investigated the potential of pollen characters to be used for the specific delimitation of
Myrsine
. Acetolyzed pollen grains were examined using light microscopy and non-acetolyzed pollen grains were analyzed by scanning electron microscopy. Pollen grains and monads of all analyzed species were isopolar, small to medium in size, and prolate spheroidal, subprolate, or prolate in shape, with (3)-4-colporate apertures, regular colpi or loxocolpi, and reticulate-granulate, granulate, rugulate-granulate, or microreticulate exine. Species considered difficult to identify based on other morphological traits were successfully distinguished using quantitative and qualitative pollen characters, confirming the importance of pollen morphology as a source of taxonomic information. Also,
Myrsine
stands out among genera of the subfamily Myrsinoideae because it shows great interspecific pollen variation, including two class sizes of pollen grains, three types of exine ornamentation, and exclusive loxocolporate pollen with inconspicuous endoapertures. This is the first report of loxocolporate pollen in Primulaceae.
Previous studies reported Psidium as one of the most difficult genera to delimit within the American Myrtaceae. Even though palynology has improved the taxonomy of Angiosperms, information about the ...usefulness of pollen morphology for taxonomic purposes in Myrtaceae remains contradictory. Here, we investigate the significance of pollen morphology for Psidium taxonomy with specific focus on its usefulness for determining species groups of taxonomic significance. Pollen traits observed by light and scanning electron microscopy were quantified and examined using cluster and ordination analyses. Average size of pollen grains was visualized by boxplots. Pollen grains of Psidium are isopolar, oblate, peroblate or oblate-spheroidal, 3-syncolporate or 4-syncolporate. The sexine ornamentation is iugulate, granulate or spinulose-granulate and differs between the mesocolpium and apocolpium. Cluster analysis revealed four distinct groups: Psidium cauliflorum (G1) and Psidium oligospermum (G3) as single-species groups; Psidium brownianum, P. oblongatum, P. ovale, P. sartorianum, P. guajava, Psidium sp. 1, Psidium sp. 2 (G2), and Psidium cattleianum, P. longipetiolatum, P. guineense, P. myrtoides (G4). Supported by ordination analysis, three traits better explained these groups: type of exine ornamentation, size of P-EV and pollen shape. The used approach efficiently distinguished related species, as well as explained species groups of taxonomic significance suggesting pollen morphology to be a significant source of information for taxonomic studies in Psidium.
•Dominant and subordinate species exhibited contrasted plant traits.•The identity of dominants had no control over subordinates’ abundance and traits.•Subordinate species segregated in space.•Spatial ...segregation was related to dissimilar trait values within subordinates.•Subordinate species have direct effects on the Restinga community composition.
Subordinate species composition and distribution are regarded as a result of the dominant species structure. However, the spatial organization of subordinate species can also be related to dispersal abilities and interactions (competition and facilitation) within subordinate species. Here, we tested the influence of dominant species on subordinate species and examined traits of subordinate species together with their spatial patterns within a tropical coastal plant community. We hypothesized that the identity of dominant species determines subordinate abundance, and dispersal and persistence trait values variation, within coexisting subordinate species. Moreover, we expected that functionally similar subordinate species aggregate in space, regarding these values. We used the relative abundance of shrubs and trees from 83 vegetation patches in 2ha of Restinga vegetation in southeastern Brazil. We determined trait value dissimilarities between dominant and subordinate species and within subordinates, and tested for the effect of the dominant species on subordinate abundance and trait values variation. Spatial cross-correlation functions were estimated for the four most abundant subordinate species with spline and Moran's I cross-correlograms. Our results showed that dominant and subordinate species exhibit contrasted trait values for dispersal and persistence. However, the composition of subordinate species in patches and the variation in their functional traits were not controlled by the identity of dominant species. Surprisingly, subordinate species segregated in space. Spatial segregation was related to dissimilar trait values within subordinates. However, the identity of dominants and patch size had no control over subordinates’ abundance. We suggest that such spatial segregation can result from competitive interactions. Dissimilar functional trait values within subordinate species seem to explain the spatial segregation of these species, principally led by differences in seed production and potential allelopathic interactions (e.g. Myrtaceae species). Therefore, independently of the identity of dominant species, subordinate species have a direct effect on the community composition of the Restinga vegetation. Together, our findings considerably increase knowledge on subordinate species in tropical plant communities and provide new insight into the potential role of subordinate species in community assembly.
Abstract This study presents a floristic-taxonomic treatment of Psidium in the state of Espírito Santo, and is a result of fieldwork combined with analyses of herbarium specimens. Fourteen species of ...the genus were recognized in Espírito Santo state (P. brownianum, P. cattleianum, P. cauliflorum, P. guajava, P. guineense, P. longipetiolatum, P. myrtoides, P. oblongatum, P. oligospermum, P. ovale, P. rhombeum, P. rufum P. sartorianum, and Psidium sp.), accounting for about 34% of the species richness estimated for the genus in the Atlantic Rainforest biome. The species occur predominantly in lowland forests up to 700 meters above sea level. These areas are highly threatened due to urbanization of coastal areas and agricultural expansion in the state Espírito Santo. Therefore, the conservation of Psidium species in this state requires the creation of more lowland protected areas.
Resumo Este estudo apresenta o tratamento florístico-taxonômico para o gênero Psidium no estado do Espírito Santo, e resulta de trabalho de campo, combinado à análise de espécimes de herbário. Quatorze espécies do gênero foram reconhecidas no Espírito Santo (P. brownianum, P. cattleianum, P. cauliflorum, P. guajava, P. guineense, P. longipetiolatum, P. myrtoides, P. oblongatum, P. oligospermum, P. ovale, P. rhombeum, P. rufum P. sartorianum e Psidium sp.), representando cerca de 34% da riqueza de espécies estimada para o gênero na Floresta Atlântica. As espécies ocorrem predominantemente em florestas baixas, até 700 metros. Essas áreas são altamente ameaçadas devido à urbanização das áreas costeiras e a expansão da agricultura do estado do Espírito Santo. Desta forma, a conservação das espécies de Psidium neste estado implica na criação de mais áreas de preservação em compreendendo florestas baixas.
Freziera atlantica is described and illustrated. The species resembles F. grisebachii in terms of the size and shape of its leaves but differs especially by the serrate and villous margin of the leaf ...blade and larger petals. The new species is known from two disjunct localities in the Atlantic Forest of Brazil, in extremely endangered environments. All known specimens of F. atlantica were collected within the last three years. This new generic record for the Brazilian Atlantic Forest highlights the need for further floristic studies of forest remnants in the states of Bahia and Espírito Santo.
QUESTION: Functional differences among climber species may reflect different strategies to cope with the environment created by the set of trees and shrubs used to reach the canopy. Moreover, climber ...diversity may be promoted and maintained by associations with subordinate woody species. Considering that functional differences among climbers may reflect this relationship, we aimed to identify trait differences among climbers, and the traits related to the association between climbers and woody species. LOCATION: Restinga de Jurubatiba National Park, a tropical sandy coastal plant community in southeast Brazil. METHODS: Relative abundances of climbers and shrubs/trees were surveyed, and climber species were described by a set of traits related to dispersal, establishment and persistence. Principal coordinate analysis was used to identify trait differences among climbers. Further, we performed principal components analysis in a community‐weighted mean trait values matrix (CWM) and compared the major pattern of variation with the abundance of dominant and subordinate woody species, and with environmental variables. RESULTS: The analyses revealed functional traits behind the association between climbers and subordinate woody species. These species are mostly characterized by the presence of latex and dry fruits, anemochorous dispersal and stem twining climbing strategy. They were associated with the subordinate shrub Erythroxylum subsessile. Tendril climbers were more generalist and were also characterized by zoochoric dispersal and the presence of endosperm. CONCLUSIONS: The associative behaviour between climbers and the subordinate shrub E. subsessile is explained by a specific set of traits present in species of the same plant family, Apocynaceae. While stem twiners were positively associated with the specialist nurse E. subsessile, tendril climbers were associated with the dominant nurses. These results offer clues to understand the presence of specialist and generalist groups of climber species in tropical plant communities, as well as community assembly through facilitation driven by subordinate species.
Resumo O estado do Espírito Santo apresenta grande variedade de ecossistemas num território relativamente pequeno. A exuberância de suas florestas vem despertando o interesse de muitos naturalistas e ...viajantes desde o século XIX, os quais deixaram registros valiosos dos primeiros anos da ocupação das "Areas Prohibidas" a leste de Minas Gerais. O cultivo do café, um dos alicerces econômicos do estado, deu início à perda dessas florestas. Tais perdas alavancaram o movimento conservacionista e a pesquisa científica no estado. A biogeografia, riqueza de espécies e de processos ecológicos nos fragmentos que restaram no Espírito Santo ainda revelam surpresas. Dentro do domínio da Floresta Atlântica, o estado abriga diferentes tipos de vegetação: Floresta Ombrófila Densa, Floresta Ombrófila Aberta, Floresta Estacional Semidecidual, Savanas, Formações Pioneiras e Refúgios Ecológicos. A descrição e classificação da vegetação do Espírito Santo ainda está inacabada tendo em vista as incertezas levantadas por alguns estudos. Também não existe um mapa da vegetação que contemple adequadamente a diversificada vegetação. A despeito de tais limitações, apresentamos descrições sucintas sobre os tipos de vegetação que vêm sendo reconhecidos na literatura moderna.
ABSTRACT The interplay between plant-plant interactions and light heterogeneity in the understory of tropical forests has rarely been examined. We aimed to identify the relative importance of the ...understory light environment and terrestrial bromeliads in explaining the abundance and spatial organization of different plant life forms along a coastal forest gradient from seashore inland in southeastern Brazil. We estimated the abundance of various life forms (herbs, woody plants, bromeliads, climbers, and palms) and the degree of light availability using hemispherical photographs in 165 plots (1 m2) within a 1.75 ha site. We used ordination methods, partial redundancy analysis (pRDA), spatial filtering using Moran’s eigenvector mapping, and Moran’s I splines. Forest cover was highly heterogeneous, but did not explain variation in abundance of life forms. Spatially, bromeliads were negatively associated with woody saplings, herbs and climbing plants at scales between 5-20 m, while the distance to seashore was found to be unrelated to these patterns. Our findings revealed that terrestrial bromeliads play an important role in the spatial organization of various life forms near the forest floor. Overall, the presence of terrestrial bromeliads and the plant area index better explained the understory vegetation than forest cover and distance to seashore.
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