ABSTRACT
The Nísia Floresta National Forest, located in Rio Grande do Norte (RN), is an important remnant of the Atlantic Forest biome in Brazil. Bromeliad tanks in this forest offer suitable breeding sites for mosquito species that may act as viral vectors, thus posing an epidemiological concern. However, studies investigating the presence of immature Culicidae in natural breeding sites in RN have thus far been restricted to Caatinga vegetation. This study investigated mosquitoes and their natural breeding sites in bromeliads growing in the Nísia Floresta National Forest. From March 2013 to February 2014, monthly samples were collected from the tanks of five randomly selected bromeliads and larvitraps placed in each of the three forest management areas. Hohenbergia catingae Ule (Hohenbergia bromeliad) is an important shelter for immature mosquitoes. Culex (Microculex) was the predominant species, representing 86% of the immature mosquitoes collected. A rare occurrence of Aedes (Stegomyia) aegypti (Linnaeus, 1762) (generally associated with urban areas under high anthropogenic influence) was observed, highlighting the importance of investigating the presence of mosquitoes in different natural habitats. An analysis of species diversity revealed that species such as Culex imitator Theobald, 1903 and Culex davisi Kumm, 1933, have a strong association with bromeliads. In tire traps (larvitraps) Aedes (Stegomyia) albopictus Skuse, 1894 was predominant. Environmental changes, such as deforestation, removal of bromeliads, and climate change in the area, can influence the migration of species and adaptation to new habitats in a peridomiciliary environment around the forest, consequently the possibility of transmission of virus and other pathogens.
Subject(s)
Culicidae , Forests , Animals , Brazil , Culicidae/physiology , Culicidae/growth & development , Biodiversity , Bromelia , Larva/growth & development , Larva/physiology , Population DensityABSTRACT
BACKGROUND: In epiphytic bromeliads, the roots used to be considered poorly functional organs in the processes of absorption and metabolization of water and nutrients, while the leaves always acted as protagonists in both functions. More recent discoveries have been changing this old view of the root system. SCOPE: In this review, we will address the old thoughts of the scientific community regarding the function performed by the roots of epiphytic bromeliads (mere holdfast structures with low physiological activity) and the importance of a reduced or lack of root system for the emergence of epiphytism. We will present indirect and direct evidence that contradicts this older hypothesis. Furthermore, the importance of the root absorptive function mainly for juvenile tankless epiphytic bromeliads and the characteristics of the root absorption process of adult epiphytic tank bromeliads will be thoroughly discussed in physiological aspects. Finally, some factors (species, substrate, environmental conditions) that influence the absorptive capability of the roots of epiphytic tank bromeliads will also be considered in this review, highlighting the importance that the absorptive role of the roots have for the plasticity of bromeliads that live on trees, which is an environment characterized by the intermittent availability of water and nutrients. CONCLUSIONS: The roots of tank-forming epiphytic bromeliads play important roles in the absorption and metabolization of nutrients and water. The importance of roots stands out mainly for juvenile tankless bromeliads since the root is the main absorptive organ. In larger plants with tank, although the leaves become the protagonists in the resource acquisition process, the roots complement the absorptive function of the leaf trichomes, resulting in a better growth of the bromeliad. The physiological and biochemical properties of the processes of absorption and distribution of resources in the tissues seem to differ between absorption by trichomes and roots.
ABSTRACT
The main difficulty for the cultivation and conservation of bromeliad species is the reduced number of propagules and slow growth of many of the species, resulting in a low propagation efficiency. Bromeliad plants are hardy and relatively easy to cultivate, with a high ornamental and ecological importance. Aiming at efficient micropropagation rates of V. hieroglyphica, a highly valued bromeliad, with very low propagation efficiency, a temporary immersion system was used and compared to semisolid and liquid static medium. Cultures obtained from in vitro germinated seeds were used as explants, maintaining their genetic diversity. Micropropagation with this simple temporary immersion system, composed of two autoclavable flasks, each with one opening for the attachment of 22 µm syringe filters, connected by a rubber stopper and an inner glass tube. In the bottom flask, an air valve is attached to the filter, which is subsequently connected to an aquarium pump and a timer and plugged to an outlet. This simple temporary immersion system showed improved micropropagation efficiency and is a method that can also be evaluated for other species.
Subject(s)
Bromeliaceae , Immersion , Catheters , Reproduction , SeedsABSTRACT
ABSTRACT Brazil is the country with the most diverse tarantula (Theraphosidae) fauna, having 215 described species. Vitalius Lucas, Silva Júnior & Bertani, 1993 is one of the most diverse and common genera in Southern, Southeastern and Central-West regions of Brazil with ten described species. Individuals of Vitalius species are large and widespread in areas of the Brazilian Atlantic Forest. A single species is known to occur in areas of Cerrado vegetation. Herein, two new species are described from areas of restinga, coastal areas typically with low vegetation and sandy soil, in the coast of the states of Rio de Janeiro (Vitalius restinga sp. nov.), Bahia and Sergipe (Vitalius sapiranga sp. nov.). Males and females of these two new species have a much longer than wide sternum. Males have a short apical keel in the male palpal bulb. The two species can be distinguished by embolus width, slender in V. restinga sp. nov. and thicker in V. sapiranga sp. nov. Females can be distinguished by the spermathecae shape, slender in V. restinga sp. nov. and broader in V. sapiranga sp. nov. These are the first known theraphosids endemic to Brazilian Atlantic Coast restingas. Biological data indicate V. sapiranga sp. nov. and maybe V. restinga sp. nov. commonly use bromeliads as retreats. It is herein hypothesized they are sister species occupying similar habitats in Brazilian coast, but separated by ca. 1,000 kilometers.
ABSTRACT
Brazil is the country with the most diverse tarantula (Theraphosidae) fauna, having 215 described species. Vitalius Lucas, Silva Júnior & Bertani, 1993 is one of the most diverse and common genera in Southern, Southeastern and Central-West regions of Brazil with ten described species. Individuals of Vitalius species are large and widespread in areas of the Brazilian Atlantic Forest. A single species is known to occur in areas of Cerrado vegetation. Herein, two new species are described from areas of restinga, coastal areas typically with low vegetation and sandy soil, in the coast of the states of Rio de Janeiro (Vitalius restinga sp. nov.), Bahia and Sergipe (Vitalius sapiranga sp. nov.). Males and females of these two new species have a much longer than wide sternum. Males have a short apical keel in the male palpal bulb. The two species can be distinguished by embolus width, slender in V. restinga sp. nov. and thicker in V. sapiranga sp. nov. Females can be distinguished by the spermathecae shape, slender in V. restinga sp. nov. and broader in V. sapiranga sp. nov. These are the first known theraphosids endemic to Brazilian Atlantic Coast restingas. Biological data indicate V. sapiranga sp. nov. and maybe V. restinga sp. nov. commonly use bromeliads as retreats. It is herein hypothesized they are sister species occupying similar habitats in Brazilian coast, but separated by ca. 1,000 kilometers.
ABSTRACT
Nidularium minutum is an ornamental bromeliad from the Brazilian Rainforest. The micropropagation of this species is essential for obtaining plants available for conservation programs or commercial use. Our study aimed to establish an efficient plant production method by in vitro sprouting. This bromeliad takes a long time to sprout in vitro, and 10% of the plants produce shoots in a culture medium without plant growth regulators (PGRs). When subcultured in a PGR-free medium, these individualized shoots can sprout like the mother plant. The Murashige and Skoog basal medium (MS) containing 1.0 mg L-1 of 6-benzylaminopurine (BAP) promoted the induction of adventitious shoots in greater than 90% of the plants after 240 days of culture with an average of more than eight shoots per plant. Approximately 100% of the in vitro-produced shoots survived after acclimatization, reaching the flowering stage. Therefore, our results showed that in vitro regeneration of N. minutum depends on the cultivation period and that plants with a higher sprouting capacity can be selected and used as micropropagation matrices, contributing to the production of this endangered bromeliad.(AU)
Subject(s)
Crops, Agricultural/growth & development , Bromeliaceae/growth & development , Plant Development , In Vitro TechniquesABSTRACT
Elpidium species exclusively inhabiting confined and temporary environments, such as those of tank-bromeliads, are a source of interesting and diverse studies on taxonomy, evolution and ecology, to name a few. However, despite its great diversity of species or potential for study, this genus (and other phytotelm members) has been poorly studied. In the last years, however, description of Elpidium species increased from six before 2013 to 11 today. This study is an effort to keep uncovering its great diversity and to go further in order to deeply understand the genus Elpidium. To this end, this study describes another species in the genus, Elpidium litoreum sp. nov., and proposes a phylogenetic reconstruction of it based on morphological characters. Our results point to the monophyly of Elpidium and puts Intrepidocythere ibipora as its sister-group. Although the phylogeny revealed some interesting relations, it also exposed some incongruities that ultimately demonstrate how superficial the current knowledge about the genus is. All these questions are discussed in detail. We see this work as at the same time an effort to better understand Elpidium and a stimulus to other researches to turn their attention to the historically neglected phytotelmata community.
ABSTRACT
Knowledge about the behavior of seeds is important to support studies to minimize the effects of predatory extractivism on ornamental bromeliads. The aim of this study was to evaluate the germination, seed morphology and post-seminal development of Hohenbergia belemii and Neoregelia compacta (Bromeliaceae) in different substrates. Seeds were disinfested with a sodium hypochlorite solution and germinated in four substrates: germitest paper; washed sand; vermiculite; and the commercial substrate Plantmax®. The experimental design was completely randomized in a 2 x 4 factorial scheme, with four repetitions and 50 seeds per repetition. The seeds were sown on the substrates and stored in plastic Gerbox® boxes, which were kept in BOD chambers with 12 hours photoperiod at constant temperature of 30ºC. Data were collected daily to calculate germination percentage and growth performance. The germination started on the 4th day after sowing (DAS) for H. belemii, with stabilization on the 11th DAS, while this occurred from the 5th DAS for N. compacta with stabilization on the 21st DAS. Germination was classified as development of epigeal and cryptocotylar seedlings for both species. The vermiculite substrate had a significant effect on seed germination, GSI (germination speed index) and growth of seedlings of both species. Our findings can support future research on seed technology and also contribute to better knowledge of the evolution of morphological characters of these bromeliad species.(AU)
Subject(s)
Seeds , Germination , Bromeliaceae , Sodium HypochloriteABSTRACT
The interspecific interactions within and between adjacent ecosystems strongly depend on the changes in their abiotic and biotic components. However, little is known about how climate change and biodiversity loss in a specific ecosystem can impact the multiple trophic interactions of different biological groups within and across ecosystems. We used natural microecosystems (tank-bromeliads) as a model system to investigate the main and interactive effects of aquatic warming and aquatic top predator loss (i.e. trophic downgrading) on trophic relationships in three integrated food web compartments: (a) aquatic micro-organisms, (b) aquatic macro-organisms and (c) terrestrial predators (i.e. via cross-ecosystem effects). The aquatic top predator loss substantially impacted the three food web compartments. In the aquatic macrofauna compartment, trophic downgrading increased the filter feeder richness and abundance directly and indirectly via an increase in detritivore richness, likely through a facilitative interaction. For the microbiota compartment, aquatic top predator loss had a negative effect on algae richness, probably via decreasing the input of nutrients from predator biological activities. Furthermore, the more active terrestrial predators responded more to aquatic top predator loss, via an increase in some components of aquatic macrofauna, than more stationary terrestrial predators. The aquatic trophic downgrading indirectly altered the richness and abundance of cursorial terrestrial predators, but these effects had different direction according to the aquatic functional group, filter feeder or other detritivores. The web-building predators were indirectly affected by aquatic trophic downgrading due to increased filter feeder richness. Aquatic warming did not affect the aquatic micro- or macro-organisms but did positively affect the abundance of web-building terrestrial predators. These results allow us to raise a predictive framework of how different anthropogenic changes predicted for the next decades, such as aquatic warming and top predator loss, could differentially affect multiple biological groups through interactions within and across ecosystems.
As interações interespecíficas dentro e entre ecossistemas adjacentes dependem fortemente das mudanças de seus componentes abióticos e bióticos. Entretanto, pouco se sabe sobre como mudanças climáticas e a perda de biodiversidade em um ecossistema específico pode impactar as múltiplas interações tróficas de diferentes grupos biológicos dentro e entre ecossistemas. Nós utilizamos micro ecossistemas naturais (bromélias-tanque) como sistema modelo para investigar os efeitos individuais e interativos do aquecimento e da perda de predadores aquáticos (simplificação trófica) nas relações tróficas em três compartimentos integrados da teia alimentar: i) micro-organismos aquáticos, ii) macroorganismos aquáticos e iii) predadores terrestres (via efeito entre ecossistemas). A perda de predadores de topo aquáticos afetou substancialmente os três compartimentos da rede trófica. No compartimento da macrofauna aquática, a simplificação trófica aumentou a riqueza e abundância de filtradores, direta e indiretamente, por meio de um aumento da riqueza de espécies de detritívoros, provavelmente através de uma interação de facilitação. Para o compartimento da microbiota, a perda de predadores de topo aquáticos teve um efeito negativo sobre a riqueza de espécies de algas, provavelmente por meio da diminuição da entrada de nutrientes provenientes das atividades biológicas dos predadores. Além disso, os predadores terrestres mais ativos responderam mais à perda de predadores de topo aquáticos, por meio de um aumento de alguns componentes da macrofauna aquática, do que predadores terrestres mais estacionários. A simplificação trófica aquática alterou indiretamente a riqueza e abundância de predadores cursoriais terrestres, mas esses efeitos tiveram direção diferente de acordo com o grupo funcional aquático, filtradores ou outros detritívoros. Os predadores construtores de teias foram indiretamente afetados pela simplificação trófica aquática devido ao aumento da riqueza de filtradores. O aquecimento aquático não afetou os micro ou macro organismos aquáticos, mas afetou positivamente a abundância de predadores terrestres construtores de teias. Esses resultados nos permitem levantar um quadro preditivo de como diferentes mudanças antropogênicas preditas para as próximas décadas, como o aquecimento e a perda de predadores de topo aquáticos, podem afetar diferencialmente vários grupos biológicos por meio de interações dentro e entre os ecossistemas.
Subject(s)
Ecosystem , Microbiota , Animals , Aquatic Organisms , Biodiversity , Food Chain , Predatory BehaviorABSTRACT
Tillandsia L. is the largest genus of the family Bromeliaceae, containing 755 species and seven subgenera. Morphoanatomical studies of leaves provide useful characteristics to phylogenetic, taxonomic, and ecological analyses. This study aims to characterize and compare the leaves of 24 species of the four subgenera of Tillandsia that occur in Bahia and also perform adaptative inferences to environmental responses. The results of the species' morphoanatomical studies were compared through dissimilarity analysis. The species have rosulate leaves with varying lengths and widths. The peltate trichomes present variation in the indument density and the length of their wing and central disk. The stomata are longitudinally distributed in one or both sides of the limb. The mesophyll is dorsiventral and presents aquiferous and chlorophyllic parenchymas. The vascular bundles are collateral and partially covered by fibers, except for Tillandsia linearis. Based on the dissimilarity analysis, it was possible to identify the formation of five groups. Group G1 was composed of T. linearis, which diverged from the other species of the subgenus. Group G2 was formed by the remaining species of the subgenus Phytarrhiza. G3 and G4 presented the species of the subgenus Diaphoranthema and Tillandsia, respectively. Group G5 gathered 11 species of the subgenus Anoplophytum and presented higher variability than the other subgenera. Based on the results, the morphoanatomical characteristics can be used to characterize and group Tillandsia species, besides confirming the morphological variability of these species to the epiphyte habit in different environments, especially xeric ones.
Subject(s)
Bromeliaceae , Tillandsia , Animals , Microscopy, Electron, Scanning , Phylogeny , Plant LeavesABSTRACT
Theory and some evidence suggest that biodiversity promotes stability. However, evidence of how trophic interactions and environmental changes modulate this relationship in multitrophic communities is lacking. Given the current scenario of biodiversity loss and climate changes, where top predators are disproportionately more affected, filling these knowledge gaps is crucial. We simulated climate warming and top predator loss in natural microcosms to investigate their direct and indirect effects on temporal stability of microbial communities and the role of underlying stabilising mechanisms. Community stability was insensitive to warming, but indirectly decreased due to top predator loss via increased mesopredator abundance and consequent reduction of species asynchrony and species stability. The magnitude of destabilising effects differed among trophic levels, being disproportionally higher at lower trophic levels (e.g. producers). Our study unravels major patterns and causal mechanisms by which trophic downgrading destabilises large food webs, regardless of climate warming scenarios.
Subject(s)
Food Chain , Microbiota , Biodiversity , Climate Change , Nutritional StatusABSTRACT
The known diversity of treefrogs of the genus Phyllodytes has rapidly increased in recent years, currently comprising 14 species. Recent field work in the Atlantic Rainforest of the state of Bahia lead to the discovery of a new large species of Phyllodytes which is herein described based on multiple evidence including morphological, acoustical and genetic data. Phyllodytes sp. nov. is one of the largest species within the genus and presents immaculate yellowish dorsum and limbs. The advertisement call of the species is composed of 7-31 notes (half pulsed/pulsatile-half harmonic) with frequency-modulated harmonics. Phyllodytes sp. nov. has a karyotype of 2n = 22 chromosomes, as also found in other species of the genus. Genetic distance values of the 16S mitochondrial rRNA among Phyllodytes sp. nov. and its congeners range between 6.4 to 10.2%. The description of another new species for this state reinforces the need for further taxonomic work with Phyllodytes in this region that has been revealed as a priority area for research and conservation of this genus.
ABSTRACT
Kerteszia cruzii is a sylvatic mosquito and the primary vector of Plasmodium spp., which can cause malaria in humans in areas outside the Amazon River basin in Brazil. Anthropic changes in the natural environments are the major drivers of massive deforestation and local climate change, with serious impacts on the dynamics of mosquito communities and on the risk of acquiring malaria. Considering the lack of information on the dynamics of malaria transmission in areas across the Atlantic Forest biome, where Ke. cruzii is the dominant vector, and the impact of climate drivers of malaria, the present study aimed to: (i) investigate the occurrence and survival rate of Ke. cruzii based on the distinct vegetation profiles found in areas across the coastal region of the Brazilian Atlantic Forest biome; (ii) estimate the extrinsic incubation period (EIP) and survival rates of P. vivax and P. falciparum parasites in Ke. cruzii under current and future scenarios. The potential distribution of Plasmodium spp. was estimated using simulation analyses under distinct scenarios of average temperature increases from 1 °C to 3.7 °C. Our results showed that two conditions are necessary to explain the occurrence and survival of Ke. cruzii: warm temperature and presence of the Atlantic Forest biome. Moreover, both Plasmodium species showed a tendency to decrease their EIP and increase their estimated survival rates in a scenario of higher temperature. Our findings support that the high-risk malaria areas may include the southern region of the distribution range of the Atlantic Forest biome in the coming years. Despite its limitations and assumptions, the present study provides robust evidence of areas with potential to be impacted by malaria incidence in a future scenario. These areas should be monitored in the next decades regarding the occurrence of the mosquito vector and the potential for malaria persistence and increased occurrence.
Subject(s)
Anopheles/parasitology , Malaria, Falciparum/parasitology , Malaria, Vivax/parasitology , Plasmodium falciparum/parasitology , Plasmodium vivax/parasitology , Animals , Anopheles/physiology , Brazil/epidemiology , Climate Change , Ecosystem , Forests , Humans , Malaria/epidemiology , Malaria, Falciparum/epidemiology , Malaria, Vivax/epidemiology , Mosquito Vectors/parasitology , Mosquito Vectors/physiologyABSTRACT
In the Yucatan Peninsula, the ponerine ant Neoponera villosa nests almost exclusively in tank bromeliads, Aechmea bracteata. In this study, we aimed to determine the factors influencing nest site selection during nest relocation which is regularly promoted by hurricanes in this area. Using ants with and without previous experience of Ae. bracteata, we tested their preference for refuges consisting of Ae. bracteata leaves over two other bromeliads, Ae. bromeliifolia and Ananas comosus. We further evaluated bromeliad-associated traits that could influence nest site selection (form and size). Workers with and without previous contact with Ae. bracteata significantly preferred this species over others, suggesting the existence of an innate attraction to this bromeliad. However, preference was not influenced by previous contact with Ae. bracteata. Workers easily discriminated between shelters of Ae. bracteata and A. comosus, but not those of the closely related Ae. bromeliifolia. In marked contrast, ants discriminated between similar sized Ae. bracteata and Ae. bromeliifolia plants, suggesting that chemical cues and plant structure play an important role. Size was also significant as they selected the largest plant when provided two dissimilar Ae. bracteata plants. Nest site selection by N. villosa workers seems to depend on innate preferences but familiarization with plant stimuli is not excluded.
ABSTRACT
Fireflies (Coleoptera: Lampyridae) are soft-bodied beetles usually associated with mesic and hydric habitats. As such, terrestrial firefly larvae are commonly found in marshy environments and stream banks, while aquatic larvae might dwell in ponds, streams, mangroves, and even brackish water. Larval biology is especially important in fireflies, as the majority of species are extremely semelparous - that is, adults rely on resources gathered during larval stages. Despite their crucial relevance in firefly biology, larvae of only near 1% firefly species have been studied, and the majority of species remain known only from adult stages. That is especially true in the Neotropical region, where they are most diverse. Here, we describe Psilocladus costae sp. nov. after the study of adults and immature stages, the latter reported for the first time for the monotypic subfamily Psilocladinae McDermott, 1964. Interestingly, adults were first obtained by rearing the larvae, the former usually fly fairly high (ca. 10 m) and are therefore seldom collected at ground level by conventional methods (e.g., active search, Malaise traps). The new species is found in the Brazilian Atlantic Rainforest, inhabiting canopy bromeliads, an unprecedented habit for fireflies.(AU)
Subject(s)
Animals , Coleoptera/anatomy & histology , Coleoptera/growth & development , Fireflies/anatomy & histology , Fireflies/growth & development , BromeliaABSTRACT
Fireflies (Coleoptera: Lampyridae) are soft-bodied beetles usually associated with mesic and hydric habitats. As such, terrestrial firefly larvae are commonly found in marshy environments and stream banks, while aquatic larvae might dwell in ponds, streams, mangroves, and even brackish water. Larval biology is especially important in fireflies, as the majority of species are extremely semelparous - that is, adults rely on resources gathered during larval stages. Despite their crucial relevance in firefly biology, larvae of only near 1% firefly species have been studied, and the majority of species remain known only from adult stages. That is especially true in the Neotropical region, where they are most diverse. Here, we describe Psilocladus costae sp. nov. after the study of adults and immature stages, the latter reported for the first time for the monotypic subfamily Psilocladinae McDermott, 1964. Interestingly, adults were first obtained by rearing the larvae, the former usually fly fairly high (ca. 10 m) and are therefore seldom collected at ground level by conventional methods (e.g., active search, Malaise traps). The new species is found in the Brazilian Atlantic Rainforest, inhabiting canopy bromeliads, an unprecedented habit for fireflies.
Subject(s)
Animals , Coleoptera/anatomy & histology , Coleoptera/growth & development , Fireflies/anatomy & histology , Fireflies/growth & development , BromeliaABSTRACT
Abstract Fireflies (Coleoptera: Lampyridae) are soft-bodied beetles usually associated with mesic and hydric habitats. As such, terrestrial firefly larvae are commonly found in marshy environments and stream banks, while aquatic larvae might dwell in ponds, streams, mangroves, and even brackish water. Larval biology is especially important in fireflies, as the majority of species are extremely semelparous - that is, adults rely on resources gathered during larval stages. Despite their crucial relevance in firefly biology, larvae of only near 1% firefly species have been studied, and the majority of species remain known only from adult stages. That is especially true in the Neotropical region, where they are most diverse. Here, we describe Psilocladus costae sp. nov. after the study of adults and immature stages, the latter reported for the first time for the monotypic subfamily Psilocladinae McDermott, 1964. Interestingly, adults were first obtained by rearing the larvae, the former usually fly fairly high (ca. 10 m) and are therefore seldom collected at ground level by conventional methods (e.g., active search, Malaise traps). The new species is found in the Brazilian Atlantic Rainforest, inhabiting canopy bromeliads, an unprecedented habit for fireflies.
ABSTRACT
Phytotelmata (sing. phytotelma) are plant-associated reservoirs of rainwater and organic debris. These freshwater ecosystems are found in tree and bamboo holes, pitcher plants, and tank-forming bromeliads. Some studies suggest that anthropic disturbance (AD) may change the physico-chemical properties (PCPs) of the water retained in the phytotelma, and indirectly impact its biota. Hence, new AD-bioindicators could be found in the phytotelma biota. To test this hypothesis, three areas of Atlantic Forest were selected, distinct only by the level of long-term AD. In these areas, we monitored the nematode trophic structure and the water PCPs in the bromeliad Neoregelia cruenta during two years (eight seasons). Significant differences among areas were found in some seasons for total nematode abundance and/or the abundance of some trophic groups, but no pattern emerged relative to the level of AD. Anthropic disturbance did not impact nematode trophic structure possibly because the water PCPs remained fairly similar in all three areas. Our results do not corroborate previous reports that AD alters phytotelma water. On the other hand, our findings support previous studies suggesting that nematodes inhabiting bromeliad phytotelma are not good candidates for AD-bioindicators.
ABSTRACT
The term phytotelma (pl. phytotelmata) designates a plant-associated reservoir of fresh water and organic debris. Phytotelmata in tank bromeliads are abundant in tropical forests, and they provide shelter, food, and water for many metazoans. Among the invertebrates known to inhabit phytotelmata, nematodes are the least studied, despite their important role in nutrient and energy cycles in freshwater ecosystems. This study was conceived to characterize the nematode trophic structure in the phytotelma of the bromeliad N. cruenta, and to identify climate and microenvironmental variables that impact it. Nematode abundance (total and per trophic group), rainfall, air temperature, the amount of organic debris fallen into the phytotelma, and eight physico-chemical properties (PCPs) of the water retained in the bromeliad tank - volume; temperature; pH; dissolved organic carbon, nitrogen, oxygen, and solids; and electrical conductivity - were monitored during two years in a natural reserve in Brazil. Bacterial and hyphal feeder nematodes predominated over other trophic groups. Nematode abundance (total and per trophic group) was not impacted by fluctuations in rainfall or air temperature. The amount of organic debris fallen into the phytotelma correlated positively with nematode abundance (total and per trophic group). Regarding the PCPs of water, the only significant correlation - positive - was between the amount of dissolved oxygen and the abundance of hyphal feeder nematodes. These results bring a clearer understanding of the ecology of nematodes inhabiting phytotelmata, which are peculiar and understudied freshwater ecosystems.
ABSTRACT
Alcantarea nahoumii(Leme) J. R. Grant is a species native to theAtlantic Forest that stands out for ornamental purposes. The objective of this work was to evaluate the in vitrogerminationof A. nahoumiiseeds and establish a micropropagation protocol for production of seedlings so as to minimize the effects of predatory extractivism and develop an in vitroconservation system. Mature seeds were disinfested, established in three culture media (MS, MS½ and MS⅓) and incubated at four temperatures (20, 25, 30 and 35ºC)in a germination chamber. In the micropropagation experiment, stem segments were introduced in MS medium supplemented with 0.5 μM of 1-naphthaleneacetic acid (NAA) and 0.0, 2.2, 4.4 and 6.6 μM of 6-benzylaminopurine (BAP). For the in vitroconservation, plantlets were established in MS or MS½ medium supplemented with 15 g L-1or 30 g L-1of sucrose. The plants were acclimated with commercial substrate. The highest seed germination percentages were promoted by temperature conditions of 20 and 25ºC, with MS culture medium. The highest multiplication rate of shoots was obtained from the treatment without addition of the growth regulator or when combined with 2.2 μM of BAP + 0.5 μM of NAA. The acclimation of the plants occurred with high survival rate. The species can be conserved in vitrounder slow growth condition for 24 months when incubated in MS medium supplemented with 30 g L-1of sucrose.