Resumo em Inglês:

ABSTRACT The growth-survival trade-off hypothesis states that functional traits of stem, wood, leaves and fruits govern acquisitive and conservative strategies of plant species that grow/survive differently in forests. We aimed to determine whether heterogeneity during the colonization of a secondary Atlantic Forest fragment causes differences in colonization-related traits and determines taxonomic composition of subplots. A total of 5,078 subplots were censused with leaf and fruit traits and height measurements being determined for each tree of each species, and with averaged-abundance-weighted values calculated for each subplot. A dendrogram was generated from the taxonomic composition of subplots using Sorensen similarity and UPGMA clustering. A total of 74,335 trees of 178 species were recorded. Clustering revealed five main groups of subplots that were tested against each other and found to differ in terms of average leaf width, leaf-width/petiole-width, wood density, mean height, height mode, fruit width and fruit length. Greater leaf averages in subplots were associated with greater fruit averages, and with higher wood densities and greater heights among groups of subplots, revealing that heterogeneity during colonization directed the communities of the 50-ha plot. The averaged values of functional traits detected subplots associated with conditions favorable to colonization, thereby reinforcing the growth-survival trade-off hypothesis.

Resumo em Inglês:

ABSTRACT Patterns of species diversity are essential to understand community structure. We aimed to determine species diversity and patterns of beta diversity in different spatial scales. We sampled three thousand individuals between the coordinates 22°10'S to 22°16'S and 47°47'W to 48°00'W to assess species diversity in three spatial scales (maximum distances of 80 m, 1,400 m, and 12,000 m), using the point-centered-quarter method. We partitioned gamma diversity into alpha and beta components. Beta diversity was partitioned into dissimilarities produced by spatial species turnover and nestedness. The contribution of beta diversity to gamma diversity was greater than that of alpha diversity in all scales, although the patterns of species diversity were similar for the evaluated scales, and was similar to that described for larger spatial scales. The sampled fragments presented means of 15 exclusive species and 47.5 species per fragment, and dissimilarities [β(SØR)=0.7] almost completely explained (94 %) by spatial species turnover. The results indicate that the remnant fragments are residual patches of an originally heterogeneous vegetation. The fragmentation processes could have progressed differently in each portion of the original vegetation, producing the current heterogeneous vegetation. Thus, there is a potential of high local species extinctions if the remnant fragments are deforested.

Resumo em Inglês:

ABSTRACT Morphological descriptions were made for pollen grains and spores extracted from samples from three sedimentary sections - Chandless 1, Purus 10 and Purus 30 - from fluvial terraces on the Chandless and Purus rivers, Acre State, Brazil. Level CH1-12 at Chandless 1 was C14-dated to 4861 - 5050 cal yr BP, P10-3 of Purus 10 was dated through the OSL method at 8200 +/- 65 yr BP, while P30-6 at Purus 30 was C14 dated to 7845 - 7998 cal yr BP. For pollen analysis, 2 cm3 of each sample was removed, treated with potassium hydroxide (KOH) and acetolysed, followed by palymorph separation with bromoform/alcohol density 2.0 solution. A total of 49 palynomorphs were morphologically described (39 pollen types and 10 Pteridophyte spores). The most frequent pollen types belonged to Anacardiaceae, Arecaceae, Euphorbiaceae, Fabaceae, Rutaceae and Amaranthaceae, while the most frequent spores belonged to Polypodiaceae and Pteridaceae. The pollen richness found in the studied samples reflects the current vegetation occupying the banks of the rivers.

Resumo em Inglês:

ABSTRACT Hydropotes are specialized epidermal structures involved in water and mineral flux into and out of the plant body. We analyzed hydropote morphology of four species of Nymphaeaceae: Nymphaea caerulea, Nymphaea lotus, Nymphaea rubra, and Victoria amazonica. Leaf samples were processed following conventional techniques for plant anatomy and for scanning and transmission electron microscopy. We observed hydropotes comprising an elongated apical sharp-pointed portion with a base composed of two to three short specialized cells. In a later developmental stage the apical sharp-pointed portion was detached and the mature hydropotes comprised an upper lens-shaped cell, a bowl-shaped cell and a large foot cell. Ultrastructural analysis revealed that the lens-shaped cell possesses labyrinthine projections in its outer periclinal wall and abundant plasmodesmata in its inner periclinal wall. Several mitochondria were present in the cytoplasm of both the lens-shaped and the bowl-shaped cells. The cytoplasm of the foot cell was reduced and possessed plastids with starch grains. The ultrastructure of the hydropotes is typical of cells involved in transporting substances and corroborates their role in the flux of substances into and out of the cell. These findings contribute to a better understanding of the functioning of hydropotes and shed light on this little-explored issue.

Resumo em Inglês:

ABSTRACT Balinese Hinduism has incorporated local animistic traditions and offerings, which play a key role in the religious ceremonies called “five holy ceremonies” or Panca yadnya. Since plants constitute fundamental elements of these offerings, we aimed to contribute to their knowledge. We analyzed plants used during ceremonies by interviewing key informants in four ancient villages of Bali (Bali aga). We identified exclusive and common species associated with different kinds of ceremonies and assessed whether there was any pattern in the selection of plants for the various offerings. We recorded 125 species (112 genera, 49 families), most of which belong to the wild ethnoflora of Bali, but also 36 species that are not native to the Malesian region. The religious relationships among ceremonies, called yadnyas, reveal specific compositions of the offerings, with the plants falling into two main groups: common, which comprises 58 plants shared by all yadnyas, and specific, mostly connected to a single yadnya. This pattern of plant use is similar to the previously detected pattern in the traditional ecological knowledge (TEK) of aga villages. The use of plants for Panca yadnya can help avoid cultural erosion related to globalization.

Resumo em Inglês:

ABSTRACT This study aims to expand knowledge of the pollen morphology of Passifloraceae and contribute to the taxonomic delimitation of the group by morphologically characterizing pollen grains of species that occur in the Brazilian state of Bahia. Thirty-six species occur in the state, one of the genus Mitostemma (M. glaziovii) and 35 of the genus Passiflora. Pollen samples were acetolysed, measured, and described using light and scanning electron microscopy. The results group the studied species into four pollen types based mainly on aperture type and number, opercular variation, and the presence/absence of ornamentation elements inside the lumina of the reticulum: Pollen type I - species belonging to the subgenera Astrophea and Deidamioides; pollen type II - subgenus Decaloba; pollen type III - subgenus Passiflora; and pollen type IV - M. glaziovii, with pollen characteristics that separate it from the other species analyzed. The results reinforce the recognition of three subgenera of Passiflora. Morphopalynologically the species have very similar pollen types except for those of the subgenus Deidamioides, which are quite diverse and thus included in another pollen type. The results reveal the importance of pollen grains for the taxonomic study of Passifloraceae.

Resumo em Inglês:

ABSTRACT Root morphology is expected to respond to environmental conditions. Two earlier studies reported predictable changes in the structure of the velamen radicum (common in monocotyledons) along rainfall gradients, which was expected from its assumed role in plant-water-relations. The present study expanded on this idea by analysing nine root traits that can be linked to root function, including velamen structure, along two moisture gradients of different spatial scales: 1) along the vertical gradient of a lowland forest in central Panama and 2) along a strong regional rainfall gradient in western Panama. All studied traits (e.g. velamen width, number of xylem poles, lignification of the exodermis) of the 45 orchid species showed substantial intraspecific and interspecific variation, but none of this (within forest) or very little of this (regional gradient) was related to the gradients. Only the community weighted means of velamen width, stele width and xylem pole number varied significantly with rainfall, with substantial effect sizes only found in the latter two traits. Our results clearly disagree with those of earlier publications, which did not include species abundance and/or rigorous statistics in their analyses. This discrepancy highlights that our understanding of the link between velamen form and function is still rudimentary.

Resumo em Inglês:

ABSTRACT Passiflora edulis Sims var. flavicarpa O. Deg. (Yellow-passion fruit) is the native plant species most used by juice industries in Brazil while its leaf extracts are widely employed in folk medicine. This study evaluated the phenolic content of leaves, roots, fruit shells and pulp of plants of P. edulis in juvenile, flowering and fruiting stages. The extent of scavenging and/or degradation of reactive nitrogen and oxygen species by plant extracts was also investigated. Leaves were the organs that most accumulated phenolics/flavonoids, regardless of plant developmental stage. Leaf extracts efficiently scavenged DPPH by up to 67 % while root and fruit shell extracts effectively captured up to 80 % O2 -. Maximum activity of catalase (51.6 mmol H2O2 min-1 mg prot-1) and ascorbate peroxidase (2.2 mmol ascorbate min-1 mg prot-1) was recorded in leaf extracts from plants in the fruiting stage. Superoxide dismutase activity reached its highest levels (37.5 U min-1 mg prot-1, on average) in plant leaves of both juvenile and fruiting plants. Overall, these results suggest that, for therapeutic purposes, parts of P. edulis should be harvested when plants are in the fruiting stage due to the excellent antioxidant properties of their extracts and their accumulation of phenolic compounds.

Resumo em Inglês:

ABSTRACT Phytoplankton structure is influenced by environmental factors, seasonal cycles and the trophic state of the system. The objective of the present study was to identify guilds of phytoplankton species that are representative of seasonality and trophic status. We evaluated phytoplankton biomass and species composition in five tropical reservoirs, with different trophic states and during rainy and dry periods. At most of the sampling sites, total biomass was higher during the rainy season. Moreover, high cyanobacterial biomass was observed in all reservoirs except for one of the mesotrophic reservoirs, which had no significant contribution from the group. Phytoplankton guilds associated with the trophic gradient and seasonality were identified. Additionally, trophic status was determined to be the most important community structure factor. The results emphasize the importance of taxonomic identification when monitoring phytoplankton structure and autoecology. Furthermore, these aquatic organisms are highly sensitive to environmental variations, making them useful tools for evaluating and/or monitoring the ecological condition of aquatic ecosystems.

Resumo em Inglês:

ABSTRACT The pollen grains of 15 species belonging to five genera (Ceiba Mill., Eriotheca Schott & Endl., Pachira Aubl., Pseudobombax Dugand, and Rhodognaphalopsis A. Robyns) of the subfamily Bombacoideae (Malvaceae s.l.) were acetolysed, measured, described and photomicrographed under light microscopy and scanning and transmission electron microscopy, in order to characterize the pollen morphology of species of the subfamily occurring in Brazil. The pollen characters studied were size, shape, exine constitution, and apertural type. Pollen grains were medium to large-sized and isopolar with a (sub)circular and (sub)triangular amb with flat, convex or concave sides; oblate to suboblate; 3(-4)-colp(or)ate or 4-5(-6)-colporate, planaperturate, sinuaperturate; equatorial calottes different or not; exine tectate or semitectate, perforate and microreticulate with or without supratectal spines. The results confirm the eurypalynous nature of the group with variation among the studied genera being mainly in the exine pattern.

Resumo em Inglês:

ABSTRACT Two new species of Mandevilla endemic to inselbergs of the state of Espírito Santo, Brazil, are described. Mandevilla alata resembles M. callista but differs by having winged stems, shorter petioles, shorter pedicels, and a white corolla with a red throat. Mandevilla ibitubana resembles M. grazielae but differs by having short-petiolate leaves, a white corolla, and shorter anthers. Illustrations, a distribution map, conservation assessments and a key to species of Mandevilla growing on inselbergs in Espirito Santo are included.

Resumo em Inglês:

ABSTRACT We present a summary of floristic variation and distribution of richness of tree and tree-like taxa (i.e., freestanding plants that reach at least 3m in height) in Brazil. We investigated composition patterns throughout phytogeographic domains and vegetation types based on 698,490 occurrence records obtained from the NeoTropTree (NTT) database, and used rarefaction and extrapolation methods to compare species richness. We delimited areas of high taxa richness in Brazil by applying the Geographic Interpolation of Endemism method. There are 9,108 tree species catalogued in NTT for Brazil, but our extrapolations indicate that the total could reach 9,525 species. Predominantly forested domains showed the greatest richness of taxa with the Amazon domain having the highest number of exclusive taxa. Fabaceae and Myrtaceae were the most represented families. The richest vegetation types were Rain Evergreen Forest and Seasonally Semideciduous Forest. Distribution patterns of richness in Brazil and among its domains were found to be controlled by different spatial scales for each taxon. Transition zones had high species richness. The patterns found here can help to identify priority areas for biodiversity conservation in Brazil.

Resumo em Inglês:

ABSTRACT Cactaceae species are karyotypically well-known with x = 11 and chromosome number variation due mainly to polyploidization. However, both assumptions are based on descriptive observations without taking an evolutionary framework of Cactaceae into account. Aiming to confirm these hypotheses in an evolutionary context, we obtained chromosome numbers for 20 species of Cactoideae, performed an extensive review of chromosome number for the family, and analyzed these data using a phylogenetic approach. The karyotypes presented here were characterized by CMA/DAPI banding, and for six species 5S and 45S rDNA sites were located. Our data, along with a survey of the literature, reinforce the long-standing hypothesis of a x = 11 as the base chromosome number for Cactaceae. They also reinforce the relevance of polyploidy in karyotype evolution of cacti, although polyploidy was important just after the diversification of subfamilies Maihuenioideae and Pereskioideae. Despite the homogeneous chromosome complements observed among cacti, chromosome banding and FISH techniques revealed informative characteristics, allowing the identification of chromosome synapomorphies, such as proximal CMA+ bands in Melocactus and proximal 5S rDNA in Pilosocereus, indicating the taxonomic potential of chromosome characterization in cacti.

Resumo em Inglês:

ABSTRACT Though they comprise 1 % of plant species on the planet, plant parasites are poorly known. They have been considered a threat to cultivated plants and to the conservation of host species in natural areas. Due to the complex interactions they have with their hosts, understanding their biology is fundamental to the development of conservation strategies for both parasite species and their hosts. We sampled two populations of the root parasite Scybalium fungiforme (Balanophoraceae) in seasonal tropical forest fragments to identify its host species and their functional attributes. Among the hosts, Croton floribundus seems to be preferred (68 % of parasitized plants), while four liana species were complementary hosts (32 %). Host species preference differed sharply among fragments and seems to be related to the successional stage of these forests. The hosts C. floribundus and the four liana species are perennial, fast growing and have large vessels, all of which are attributes that enable high water and nutrient acquisition efficiency. Despite a lack of clear host specificity at the species level, functional convergence among parasitized species suggests that host specificity is mediated by functional traits.

Resumo em Inglês:

ABSTRACT Ecological transitions usually represent vulnerable ecosystems and high biodiversity. Investigating their drivers is important from both biogeographic and conservationist perspectives. One of these transitions is situated between the two largest biogeographic domains of South America - the Amazon and the Cerrado. We evaluated variation in tree floristic composition throughout this transition and assessed which factors explain this variation. We used 17,240 records of occurrences of 2,530 tree species from the NeotropTree database. We investigated variation in floristic composition using UPGMA cluster analysis with bootstrap resampling and NMDS ordination, and modeled the distribution of species in relation to environmental and spatial predictors by means of transformation-based Redundancy Canonical Analysis (tb-RDA) and variance partitioning. We found four general floristic groups: 1) flooded forests; 2) white sand dwarf-forests; 3) savannic and dwarf forests; and 4) non-flooded forest types. Floristic variation along the transition was influenced by the environment, especially variables related to fire and soil moisture, and by space, especially variables acting on broader scales. Correspondence between the environmental heterogeneity found throughout the transition and our results demonstrates once again the importance of conserving biogeographical transition zones in general, and the most comprehensive of South America in particular.

Resumo em Inglês:

ABSTRACT Cleistocactus baumannii is the only ornithophilous cactus species in the Brazilian Chaco. In addition, this species of Cactaceae invests heavily in flowering in the ecoregion. Such characteristics motivated us to evaluate the temporal availability of flowers in the context of its floral visitors. The reproductive system of C. baumannii, the number of individuals in flowering, flower abundance and the frequency and richness of floral visitors were evaluated and quantified. Nectar robbery was a frequent phenomenon in the studied population; therefore, we compared the pollen load deposited on the stigma of damaged (robbery) and undamaged flowers. In the Brazilian Chaco, C. baumannii is self-incompatible and has a continuous flowering pattern, providing floral resources throughout the year for nine species of floral visitors. One hummingbird species acted as a potential pollinator, and we consider Xylocopa splendidula to be a nectar robber. We found stigma of flowers damaged by nectar robbers to have lower pollen loads than those of undamaged flowers. This study highlights the importance of studying reproductive traits in different populations to understand changes in the reproductive success of plant species at different scales and possible causes, such as availability of floral visitors, incidence of robbers and flowering patterns.

Resumo em Inglês:

ABSTRACT The family Cactaceae possesses considerable floral diversity and is exclusively zoophilic. Cipocereus crassisepalus is an endangered species of columnar cactus, whose floral characteristics fit the chiropterophily syndrome. This study aimed to assess the correspondence between floral traits and pollinators and whether the pollination system of C. crassisepalus is specialized, as suggested by the hypothesis of geographical dichotomy. Hand pollination treatments demonstrated that C. crassisepalus depends on cross-pollen flow mediated by pollinators to set fruit and seeds. Nocturnal film recordings, diurnal observations, analyses of pollen loads of flower visitors and visitor exclusion experiments provided strong evidence that bats are the sole pollinators of this cactus. During two flowering seasons, pollen grains of C. crassisepalus were found only on the bodies of the bat Anoura caudifer. Cipocereus crassisepalus possesses a pollination system specialized on nectar-feeding bats, which corroborates the geographical dichotomy hypothesis.

Resumo em Inglês:

ABSTRACT Fire-related cues may enhance seed recruitment in flammable ecosystems and differences in fire-germination responses of invasive vs. native species can drive the invasion process. We evaluated the effects of heat shock and smoke water solution treatment on seed germination of invasive (Melinis minutiflora, Urochloa decumbens, U. brizantha) and native grasses (Axonopus pressus, Aristida setifolia, Gymnopogon foliosus) of the Cerrado. The effect of fire temperature was tested by exposing seeds to heat shock treatments of 60, 100, and 200 °C for one minute, comparing them to untreated seeds. The effect of smoke was tested by soaking seeds for 24-h in an aqueous smoke comparing them to seeds soaked in distilled water. Differences among treatments were evaluated by ANOVA and randomization tests. None of the tested species had germination stimulated by the temperature or smoke. Both species of Urochloa experienced decreased viability with increasing temperature, while seeds of native species and M. minutiflora tolerated heat shock up to 200 °C. The invasive grasses usually germinated faster than the native grasses. Germination time is therefore a crucial trait driving the invasion process, irrespective of fire-related cues. Other seed traits (e.g. dormancy) and higher resprouting capacity may help invasive species to persist in frequently burned savannas.

Resumo em Inglês:

ABSTRACT The flood pulse of black water rivers in the Amazon basin determines the composition of species along the flood gradient in igapó forests. The Balbina dam, built on the Uatumã River, has altered the flood pulse and caused changes in the floristic composition of adult trees throughout the downstream area. There is a lack of studies on how communities of seedlings in igapó forests respond to changes in the flood pulse. This study investigates the response of seedling communities in the igapó forest downstream the Balbina dam and compares it with two pristine areas. The areas were sampled with transects of 1x25 m within 36 plots (25x25 m) along the flood gradient. Richness and dominance were calculated by simple regression and ordination analyses. The pristine areas had the same pattern of richness, dominance and genera distribution along the flood gradient. However, the affected Uatumã area formed different groups of genera by NMDS analysis, which divided them along the flood gradient with significantly increased dominance of three genera. The insertion of the Balbina dam resulted a loss of lateral and longitudinal connectivity for the Uatumã River, and the alteration to seedling communities may alter the future landscape of downstream igapó forests.

Resumo em Inglês:

ABSTRACT Tree ferns are important elements of tropical forests, mainly because they are common and provide microhabitats for epiphytic plants. Due to their ecological importance, the aim of this study was to evaluate population structure, distribution, and influence of environmental variables on tree ferns in the state of Santa Catarina, southern Brazil. All tree ferns with a diameter at breast height ≥ 10 cm on 418 sampling units (SUs) systematically distributed throughout the study area were measured (total sampled area of ​​153.4 ha). Population structure was evaluated through classical phytosociological parameters and the relationships among dominance and environmental variables were evaluated through multiple linear regression models. Dicksonia sellowiana presented the greatest importance value among all species (IV = 13.19 %), followed by Alsophila setosa (IV = 4.37 %) and Cyathea phalerata (IV = 2.71 %). Altitude and mean rainfall of the driest quarter were significantly related to the dominance of D. sellowiana in most of the SUs. The mean temperature of the driest quarter and aspect were significantly related to the dominance of Cyatheaceae. Our study demonstrates that tree ferns are important elements of forest communities in the state of Santa Catarina.

Resumo em Inglês:

ABSTRACT We describe the leaf anatomy of 42 of the 60 species of the genus Banisteriopsis, one of the largest and most diverse genera of Malpighiaceae in the Cerrado domain. Our aim was to identify anatomical leaf characters useful for the taxonomy and systematics of this morphological diverse genus. Expanded leaves from herbarium specimens were rehydrated and processed according to usual anatomical methods for analysis under light microscopy. All characters were compared using the Unweighted Pair Group Method with Arithmetic Mean algorithm and expressed in dendrograms. The most useful leaf anatomical characters were petiole contour, presence/absence of vascular bundles in the petiole, the position of the vascular bundles in the petiole, shape of the midrib, presence/absence of sheath extension, mesophyll type, and both the presence/absence and shape of leaf glands. Our study indicates that the morphological groups proposed in the literature for Banisteriopsis are natural groups.