RESUMO
PREMISE: Salt tolerance has rarely been investigated regionally in the neotropics and even more rarely in Orchidaceae, one of the largest families. Therefore, investigating local adaptation to salt spray and its physiological basis in Epidendrum fulgens, a neotropical orchid species, brings important new insights. METHODS: We assessed the degree of salt tolerance in E. fulgens by testing whether coastal populations are more tolerant to salt, which could point to local adaptation. To understand the physiological basis of such salt tolerance, we exposed wild-collected individuals to salt spray for 60 days, then measured leaf expansion, osmotic potential, sodium leaf concentration, chlorophyll leaf index, chlorophyll fluorescence, relative growth rate, and pressure-volume curves. RESULTS: There is no local adaptation to salt spray since both inland and coastal plants have a high tolerance to salt stress. This tolerance is explained by the ability to tolerate high concentrations of salt in leaf tissues, which is related to the high succulence displayed by this species. CONCLUSIONS: We showed an unprecedented salt tolerance level for an orchid species, highlighting our limited knowledge of that trait beyond the traditional studied groups. Another interesting finding is that salt tolerance in E. fulgens is linked to succulence, is widespread, and is not the result of local adaptation. We suggest that E. fulgens and its allied species could be an interesting group to explore the evolution of important traits related to tolerance to salt stress, like succulence.
Assuntos
Adaptação Fisiológica , Orchidaceae , Folhas de Planta , Tolerância ao Sal , Orchidaceae/fisiologia , Orchidaceae/efeitos dos fármacos , Folhas de Planta/fisiologia , Folhas de Planta/efeitos dos fármacos , Cloreto de Sódio/farmacologia , Clorofila/metabolismo , Sódio/metabolismo , Clima TropicalRESUMO
BACKGROUND AND AIMS: Orchid seeds are reputed to be short lived in dry, cold storage conditions, potentially limiting the use of conventional seed banks for long-term ex situ conservation. This work explores whether Cattleya seeds are long lived or not during conventional storage (predried to ~12 % relative humidity, then stored at -18 °C). METHODS: We explored the possible interaction of factors influencing seed lifespan in eight species of the genus Cattleya using physiological (germination and vigour), biochemical (gas chromatography), biophysical (differential scanning calorimetry) and morphometric methods. Seeds were desiccated to ~3 % moisture content and stored at -18 °C for more than a decade, and seed quality was measured via three in vitro germination techniques. Tetrazolium staining was also used to monitor seed viability during storage. The morphometric and germination data were subjected to ANOVA and cluster analysis, and seed lifespan was subjected to probit analysis. KEY RESULTS: Seeds of all Cattleya species were found to be desiccation tolerant, with predicted storage lifespans (P50y) of ~30 years for six species and much longer for two species. Cluster analysis showed that the three species with the longest-lived seeds had smaller (9-11 %) airspaces around the embryo. The post-storage germination method impacted the quality assessment; seeds equilibrated at room temperature for 24 h or in 10 % sucrose solution had improved germination, particularly for the seeds with the smallest embryos. Chromatography revealed that the seeds of all eight species were rich in linoleic acid, and differential scanning calorimetry identified a peak that might be auxiliary to selecting long-lived seeds. CONCLUSIONS: These findings show that not all orchids produce seeds that are short lived, and our trait analyses might help to strengthen prediction of seed longevity in diverse orchid species.
Assuntos
Germinação , Orchidaceae , Banco de Sementes , Sementes , Sementes/fisiologia , Sementes/crescimento & desenvolvimento , Orchidaceae/fisiologia , Orchidaceae/crescimento & desenvolvimento , Orchidaceae/anatomia & histologia , Germinação/fisiologia , Dessecação , Varredura Diferencial de CalorimetriaRESUMO
The aerial environment appears to structurally modify roots, which frequently show specializations for absorbing water and nutrients. Among those specializations are the velamen, a multiseriate epidermis generally composed of dead mature cells, and greater degrees of lignification in the endodermis, exodermis, and pith. Vanilla phaeantha is a hemiepiphyte used here as a model of study to determine which root characteristics demonstrate the most plasticity in response to aerial and terrestrial environments. It produces roots growing under three conditions: (1) aerial and free, growing from the highest branches towards the ground; (2) aerial roots attached to the phorophyte; and (3) terrestrial. Samples taken 3 cm from the apices were used to prepare histological slides. The tissues and other anatomical structures were measured and histochemically characterized. The most plastic characteristics were the external periclinal thicknesses of the exodermis and the total area occupied by the aerenchyma lacunae. The free roots were the longest, did not evidence root hairs, and had the largest number of the aerenchyma lacunae; they also evidenced greater thicknesses of the exodermis in contact with the epidermis walls that helped maintain their shapes. Terrestrial roots had root hairs around the entire circumference and intense infestations of mycorrhiza, indicating their involvement in nutrient acquisition. The adhering roots evidenced free regions similar to those of aerial roots, as well as adhering regions showed characteristics similar to terrestrial roots (with root hairs and mycorrhiza infestations).
Assuntos
Orchidaceae , Vanilla , Orchidaceae/fisiologia , Raízes de Plantas , ÁguaRESUMO
Oncidiinae is one of the most important subtribes among the Neotropical orchids, with an enormous diversity of floral morphology and secretory structures. This subtribe attracts a diverse array of pollinators which explore a variety of floral resources of its flowers. In this paper we provide a detailed investigation of the floral anatomy of 32 species of micro Oncidiinae. We applied histochemical tests in order to determine the diversity of the glands and rewards. The diversity of secretory flower structures and rewards was related to the group of pollinators known for this subtribe. We verified that half of the species (16 species, 50%) secrete oil as a resource, being pollinated by female of solitary bees. Species of some distinct nectar-secreting genera (four species, 12.5%) are pollinated by a range of nectar-searching animals. Species of the genus Notylia (four species, 12.5%) release floral perfumes that reward male Euglossini bees. Most of the investigated species (six species, 18.75%) possess osmophores that are involved in pollinator attraction. Two species of Capanemia (6.25%) do not offer any floral reward, suggesting that pollination by food deception is involved. There are strong variations in the anatomy of reward-producing structures and resources in Oncidiinae. The diversity of floral rewards affects the range of pollinators, which are related to the diversification of this subtribe throughout the Neotropics. The understanding of relationships between Oncidiinae species and their pollinators is crucial to our knowledge of the evolution of pollination systems in this huge plant family represented by the orchids.
Assuntos
Abelhas , Flores , Orchidaceae , Polinização , Animais , Feminino , Flores/anatomia & histologia , Interações Hospedeiro-Parasita/fisiologia , Masculino , Orchidaceae/anatomia & histologia , Orchidaceae/fisiologia , Perfumes , Néctar de Plantas , Óleos de Plantas , Especificidade da EspécieRESUMO
Light is one of the factors that influence the germination and initial establishment of orchids under in vitro cultivation. This study evaluated the effect of different light sources on these stages in in vitro cultivation of Schomburgkia crispa Lindl. After sowing in an aseptic environment, we stored the cultures in a screened greenhouse (natural light) or in a growth room with the following light sources: 3,000 K yellow LED; 6,500 K white LED [1]; 6,500 K white LED [2]; or 6,500 K white fluorescent lamp (control). We assessed germination percentage and initial seedling establishment at 45 and 90 days after sowing. Light did not influence the germination of S. crispa. However, the use of 3,000 K LED provided a faster initial establishment of S. crispa when compared to the other light sources, also presenting lower seedling mortality. Thus, the light source 3,000 K LED is a potential substitute for the 6,500 K fluorescent lamps and LEDs used in growth rooms in in vitro culture laboratories.(AU)
A luz é um dos fatores que influenciam a germinação e o estabelecimento inicial no cultivo in vitro de orquídeas. Assim, objetivou-se avaliar o efeito de diferentes fontes de luz na germinação e no estabelecimento inicial in vitro de Schomburgkia crispa Lindl. Após semeadura em ambiente asséptico, as culturas foram acondicionadas em viveiro telado (luz natural) ou em sala de crescimento nas seguintes fontes luminosas: LEDs amarelo 3.000 K, branco 6.500 K [1], branco 6.500 K [2] ou lâmpada fluorescente branca 6.500 K (controle). Aos 45 e 90 dias após a semeadura foi avaliada a porcentagem de germinação e o estabelecimento inicial dos propágulos. A luz não influenciou a germinação das sementes de S. crispa, mas a utilização do LED 3.000 K proporcionou estabelecimento inicial de S. crispa em menor período e com menor mortalidade das plântulas, quando comparado com as demais fontes de luz utilizadas. A fonte de luz LED 3.000 K pode ser indicada como um substituto potencial para as lâmpadas fluorescentes e LEDs 6.500 K, utilizadas em salas de crescimento em laboratórios de cultivo in vitro.(AU)
Assuntos
Orchidaceae/crescimento & desenvolvimento , Orchidaceae/fisiologia , Orchidaceae/efeitos da radiaçãoRESUMO
BACKGROUND: There is a large amount of industrial wastewater produced by the mushroom industry during the canning processing each year, which could provide abundant carbon, nitrogen and inorganic salts for microbial growth. The aim of this study was to optimize the culture conditions for Bacillus licheniformis cultured in the Agaricus bisporus industrial wastewater to produce the agricultural microbial fertilizer. RESULTS: In this work, the maximal biomass of B. licheniformis could be obtained under the following culture conditions: 33.7°C, pH 7.0, 221 rpm shaking speed, 0.5% wastewater, 2 (v:v, %) inoculum dose, loading liquid of 60 mL/250 mL and a culture time of 24 h, and the average experimental value obtained was 1.35 ± 0.04 × 109 Obj/mL, which was within the 95% confidence interval of the predicted model (1.291.38 × 109 Obj/mL), and met the national microbial fertilizers' standard in China. Furthermore, the field experiment results showed that the fermentation broth of B. licheniformis could significantly improve the yield of Anoectochilus roxburghii. CONCLUSIONS: Agaricus bisporus industrial wastewater can be used to produce agricultural microbial fertilizer.
Assuntos
Orchidaceae/fisiologia , Fertilizantes/microbiologia , Bacillus licheniformis/fisiologia , Agaricus , Fermentação , Águas Residuárias , Citometria de Fluxo , Concentração de Íons de Hidrogênio , Resíduos IndustriaisRESUMO
The production of triploids and apomictic reproduction are important processes for polyploid establishment and cytotype coexistence, but we know little about the interaction between triploids and facultatively apomictic plants. To bridge this gap, we studied the pollen-dependent, facultatively apomictic orchid Zygopetalum mackayi from high-elevation outcrops of southeast Brazil. We described the nature of the contact between Z. mackayi cytotypes and patterns of genetic diversity and structure based on eight microsatellite markers and 155 individuals of pure tetraploid, pure diploid and mixed cytotype populations. Our results revealed high values of genetic and genotypic diversity within all populations of Z. mackayi. Each cytotype emerged as a genetic distinct cluster, combining individuals from different populations. Triploids clustered in an intermediate position between diploids and tetraploids. Most genetic variance is associated with individuals within populations and genetic differentiation is high among populations. Mixed cytotype populations of Z. mackayi originate from secondary contact. Triploids are hybrids between diploids and tetraploids and likely act as a bridge. Our results point to the predominance of sexual reproduction in all populations but do not corroborate previous basic chromosome number for this species. Polyploidy rather than facultative apomixis may explain the larger geographic distribution of tetraploids of Z. mackayi.
Assuntos
Diploide , Hibridização Genética , Orchidaceae , Tetraploidia , Brasil , Orchidaceae/fisiologia , Poliploidia , ReproduçãoRESUMO
Intraspecific floral colour polymorphism is a common trait of food deceptive orchids, which lure pollinators with variable, attractive signals, without providing food resources. The variable signals are thought to hinder avoidance learning of deceptive flowers by pollinators. Here, we analysed the cognitive mechanisms underlying the choice of free-flying stingless bees Scaptotrigona aff. depilis trained to visit a patch of artificial flowers that displayed the colours of Ionopsis utricularioides, a food deceptive orchid. Bees were trained in the presence of a non-rewarding colour and later tested with that colour vs. alternative colours. We simulated a discrete-polymorphism scenario with two distinct non-rewarding test colours, and a continuous-polymorphism scenario with three non-rewarding test colours aligned along a chromatic continuum. Bees learned to avoid the non-rewarding colour experienced during training. They thus preferred the novel non-rewarding colour in the discrete-polymorphic situation, and generalized their avoidance to the adjacent colour of the continuum in the continuous-polymorphism situation, favouring thereby the most distant colour. Bees also visited less flowers and abandoned faster a non-rewarding monomorphic patch than a non-rewarding polymorphic patch. Our cognitive analyses thus reveal that variable deceptive orchids disrupt avoidance learning by pollinators and exploit their generalization abilities, which make them favour distinct morphs.
Assuntos
Abelhas/fisiologia , Cognição/fisiologia , Comportamento Alimentar/fisiologia , Polinização/fisiologia , Animais , Aprendizagem da Esquiva/fisiologia , Cor , Flores/fisiologia , Orchidaceae/fisiologia , Pólen/fisiologiaRESUMO
Burkholderia species have different lifestyles establishing mutualist or pathogenic associations with plants and animals. Changes in the ecological behavior of these bacteria may depend on genetic variations in response to niche adaptation. Here, we studied 15 Burkholderia strains isolated from different environments with respect to genetic and phenotypic traits. By Multilocus Sequence Analysis (MLSA) these isolates fell into 6 distinct groups. MLSA clusters did not correlate with strain antibiotic sensitivity, but with the bacterial ability to produce antimicrobial compounds and control orchid necrosis. Further, the B. seminalis strain TC3.4.2R3, a mutualistic bacterium, was inoculated into orchid plants and the interaction with the host was evaluated by analyzing the plant response and the bacterial oxidative stress response in planta. TC3.4.2R3 responded to plant colonization by increasing its own growth rate and by differential gene regulation upon oxidative stress caused by the plant, while reducing the plant's membrane lipid peroxidation. The bacterial responses to oxidative stress were recapitulated by bacterial exposure to the herbicide paraquat. We suggest that the ability of Burkholderia species to successfully establish in the rhizosphere correlates with genetic variation, whereas traits associated with antibiotic resistance are more likely to be categorized as strain specific.
Assuntos
Adaptação Biológica/genética , Infecções por Burkholderia , Burkholderia , Interações entre Hospedeiro e Microrganismos , Orchidaceae/microbiologia , Aclimatação/genética , Anti-Infecciosos/farmacologia , Agentes de Controle Biológico/farmacologia , Burkholderia/genética , Burkholderia/crescimento & desenvolvimento , Burkholderia/isolamento & purificação , Burkholderia/metabolismo , Resistência Microbiana a Medicamentos/genética , Endófitos/genética , Endófitos/crescimento & desenvolvimento , Endófitos/isolamento & purificação , Endófitos/metabolismo , Genes Bacterianos , Ilhas Genômicas , Genótipo , Peroxidação de Lipídeos , Tipagem de Sequências Multilocus , Orchidaceae/fisiologia , Estresse Oxidativo/genética , Fenótipo , Filogenia , Doenças das Plantas/microbiologia , Doenças das Plantas/terapia , RNA Ribossômico 16S/genética , Simbiose , TranscriptomaRESUMO
O presente trabalho teve como objetivo avaliar diferentes substratos no cultivo da espécie Cyrtopodium cardiochilum (Orchidaceae). As plantas foram cultivadas em vasos de polietileno, em casa de vegetação com tela de sombreamento de polipropileno de 60% de retenção de luminosidade. Os tratamentos constituíram-se de brita de gnaisse (granulometria variando de 8-15 mm), argila expandida (15-22 mm de diâmetro), seixo rolado (8-15 mm), casca de coco em cubos (coxim) e vermiculita. Foram analisadas também as combinações de brita e argila expandida, brita e seixo, argila expandida e seixo, na proporção 1:1 (v/v); brita, argila expandida e seixo na proporção 1:1:1 (v/v/v); e brita, argila expandida, seixo e vermiculita na proporção 1:1:1:1 (v/v/v/v). Após seis meses de instalação do experimento foram avaliadas as seguintes variáveis: altura das plantas, diâmetro dos pseudobulbos, número de folhas, produção de massa de matéria seca total (MST), da parte aérea (MSPA) e do sistema radicular (MSR). Utilizou-se o delineamento experimental em blocos casualizados, composto por nove tratamentos e oito repetições. Não houve diferença entre os tratamentos para: altura de planta, número de folhas, diâmetro dos pseudobulbos e MSR. Para a MSPA e MST observou-se diferença entre os substratos, com destaque para o tratamento argila expandida + brita de gnaisse. Conclui-se que todos os substratos utilizados podem ser utilizados no cultivo de C. cardiochilum, destacando-se o substrato argila expandida + brita de gnaisse na proporção de 1:1 (v/v).(AU)
This study aimed to evaluate the effect of different substrates in the cultivation of the species Cyrtopodium cardiochilum (Orchidaceae). Plants were grown in plastic pots in a greenhouse with 60% shading, obtained through a polypropylene mesh black type "shading". The treatments consisted of gneiss gravel (grain size ranging from 8-15 mm), expanded clay (15-22 mm diameter), pebbles (8-15 mm), coconut cubes (cushion) and vermiculite. The combinations of gravel and expanded clay, gravel and pebble, expanded clay and pebble, in a 1:1 (v/v); gravel, expanded clay and pebble in the proportion 1:1:1 (v/ v/v); and gravel, expanded clay, vermiculite and pebble in the proportion 1:1:1:1 (v/v/v/v) were also tested. After six months of trial installation the variables were evaluated: plant height, diameter of the pseudobulbs, number of leaves, mass production of total dry matter (TDM) and shoot (DMS) and root system (DMRS) dry matter. It was used the experimental randomized block design, consisting of nine treatments and eight repetitions. There was no difference between treatments for: plant height, leaf number, diameter of the pseudobulbs and DMRS. For the DMS and TDM was observed difference between the substrates, especially for the treatment expanded clay + gravel gneiss. It concluded that all tested substrates may be used in cultivation of C. cardiochilum, high lighting the substrate expanded clay + gneiss gravel in the ratio 1:1 (v/v).(AU)
Assuntos
Orchidaceae/crescimento & desenvolvimento , Orchidaceae/fisiologia , Substratos para Tratamento Biológico/métodos , Flores/crescimento & desenvolvimento , Flores/fisiologiaRESUMO
O presente trabalho teve como objetivo avaliar diferentes substratos no cultivo da espécie Cyrtopodium cardiochilum (Orchidaceae). As plantas foram cultivadas em vasos de polietileno, em casa de vegetação com tela de sombreamento de polipropileno de 60% de retenção de luminosidade. Os tratamentos constituíram-se de brita de gnaisse (granulometria variando de 8-15 mm), argila expandida (15-22 mm de diâmetro), seixo rolado (8-15 mm), casca de coco em cubos (coxim) e vermiculita. Foram analisadas também as combinações de brita e argila expandida, brita e seixo, argila expandida e seixo, na proporção 1:1 (v/v); brita, argila expandida e seixo na proporção 1:1:1 (v/v/v); e brita, argila expandida, seixo e vermiculita na proporção 1:1:1:1 (v/v/v/v). Após seis meses de instalação do experimento foram avaliadas as seguintes variáveis: altura das plantas, diâmetro dos pseudobulbos, número de folhas, produção de massa de matéria seca total (MST), da parte aérea (MSPA) e do sistema radicular (MSR). Utilizou-se o delineamento experimental em blocos casualizados, composto por nove tratamentos e oito repetições. Não houve diferença entre os tratamentos para: altura de planta, número de folhas, diâmetro dos pseudobulbos e MSR. Para a MSPA e MST observou-se diferença entre os substratos, com destaque para o tratamento argila expandida + brita de gnaisse. Conclui-se que todos os substratos utilizados podem ser utilizados no cultivo de C. cardiochilum, destacando-se o substrato argila expandida + brita de gnaisse na proporção de 1:1 (v/v).
This study aimed to evaluate the effect of different substrates in the cultivation of the species Cyrtopodium cardiochilum (Orchidaceae). Plants were grown in plastic pots in a greenhouse with 60% shading, obtained through a polypropylene mesh black type "shading". The treatments consisted of gneiss gravel (grain size ranging from 8-15 mm), expanded clay (15-22 mm diameter), pebbles (8-15 mm), coconut cubes (cushion) and vermiculite. The combinations of gravel and expanded clay, gravel and pebble, expanded clay and pebble, in a 1:1 (v/v); gravel, expanded clay and pebble in the proportion 1:1:1 (v/ v/v); and gravel, expanded clay, vermiculite and pebble in the proportion 1:1:1:1 (v/v/v/v) were also tested. After six months of trial installation the variables were evaluated: plant height, diameter of the pseudobulbs, number of leaves, mass production of total dry matter (TDM) and shoot (DMS) and root system (DMRS) dry matter. It was used the experimental randomized block design, consisting of nine treatments and eight repetitions. There was no difference between treatments for: plant height, leaf number, diameter of the pseudobulbs and DMRS. For the DMS and TDM was observed difference between the substrates, especially for the treatment expanded clay + gravel gneiss. It concluded that all tested substrates may be used in cultivation of C. cardiochilum, high lighting the substrate expanded clay + gneiss gravel in the ratio 1:1 (v/v).
Assuntos
Flores/crescimento & desenvolvimento , Flores/fisiologia , Orchidaceae/crescimento & desenvolvimento , Orchidaceae/fisiologia , Substratos para Tratamento Biológico/métodosRESUMO
Acianthera section Pleurobotryae is one of ten sections of the genus Acianthera and include four species endemic to the Atlantic Forest. The objective of this study was to describe comparatively the anatomy of vegetative organs and floral micromorphology of all species of Acianthera section Pleurobotryae in order to identify diagnostic characters between them and synapomorphies for the section in relation of other sections of the genus. We analyzed roots, ramicauls, leaves and flowers of 15 species, covering eight of the nine sections of Acianthera, using light microscopy and scanning electron microscopy. Acianthera section Pleurobotryae is a monophyletic group and the cladistic analyses of anatomical and flower micromorphology data, combined with molecular data, support internal relationship hypotheses among the representatives of this section. The synapomorphies identified for A. sect. Pleurobotryae are based on leaf anatomy: unifacial leaves, round or elliptical in cross-section, round leaves with vascular bundles organized in concentric circles, and mesophyll with 28 to 30 cell layers. Within the section, the clade (A. crepiniana + A. mantiquyrana) presented more differences in vegetative organ morphology and higher support values in combined analyses when compared to the second clade, (A. atropurpurea + A. hatschbachii). For each of these clades an exclusive set of homoplasies of vegetative and floral organs were also identified. The results support the argument that vegetative organs are more evolutionarily stable in comparison to reproductive organs and thus helpful for inference of internal phylogenetic relationships in Acianthera, while flowers are highly variable, perhaps due to the diversity of pollinator attraction mechanisms. The analyses indicate that the elliptical leaves observed in A. crepiniana have originated from round leaves observed in the other species of this section, suggesting an adaptation to increase the area of exposure of the leaf and better the efficiency of capture of sunlight in shaded environments such as the Atlantic Forest. The presence of papillose regions in both vegetative and floral organs indicated that micromorphological characters are also useful for the delimitation of species and sections within the genus.
Assuntos
Evolução Biológica , Flores , Orchidaceae , Filogenia , Folhas de Planta , Polinização , Flores/fisiologia , Flores/ultraestrutura , Microscopia Eletrônica de Varredura , Orchidaceae/classificação , Orchidaceae/fisiologia , Orchidaceae/ultraestrutura , Folhas de Planta/fisiologia , Folhas de Planta/ultraestrutura , Polinização/fisiologiaRESUMO
Euglossini (Hymenoptera: Apidae, Apini), also known as orchid bees, are endemic to the Neotropical region (Nemésio and Rasmussem, 2011). They are well-known and widely distributed taxon in the Atlantic Forest with more than 60 species (included in four distinct genera) registered in this biome (Nemésio, 2009; Garraffoni et al., 2017). The Atlantic Rain Forest originally occupied about 15% of the Brazilian territory, but it was completely fragmented in forest remnants, and now covers 11-16% of its original area (Ribeiro et al., 2009; Joly et al., 2014). Our knowledge about orchid bee diversity in urban forest fragments is very scarce (Nemésio and Silveira, 2007; Cordeiro et al., 2013), although diverse communities of wild bees have been surprisingly found in cities around the world (Nemésio and Silveira, 2007; Burr et al., 2016). Thus, our aim in this study was a rapid assessment of the orchid bee fauna in the vicinity of an Atlantic Forest remain. The strategy of intensive sampling over a few days in the rainy season are common and has been demonstrated to be very useful to know the orchid bee fauna of an area (Nemésio, 2013a, b). Data were collected in an urban area (22º4940S-47º0610W; altitude 630 m), among fruit and ornamental trees, distant 200 m of the east edge of an Atlantic Forest remnant called Santa Genebra Forest (Campinas, SP), the second larger urban forest in Brazil (252 ha). It is a semideciduous forest and the regional climate is the Cfa of Köppen (humid subtropical with a hot summer). Orchid bee males were collected at a fixed site using seven bait traps as described in Viotti et al. (2013), and bottles of 0.5 L. Each trap received one of the seven baits: 1,8-cineole, eugenol, vanillin, β-ionone, benzyl acetate, methyl trans-cinnamate, and methyl salicylate; and were randomly hanged in shaded branches at about 1.5 m above the ground and distant at least 2 m from each other. The collections were done during five consecutive days (from day 6th to 10th) in February of both 2015 and 2016, from 9:00 to 17:00 h (when the bees are most active). The scents were replaced every day, and cineole three times a day. Captured bees were pinned, identified and deposited at Coleção de Abelhas da Universidade Federal dos Vales do Jequitinhonha e Mucuri. Taxonomic decisions were based on Moure's Bee Catalogue (Moure et al., 2012). Species accumulation curves were constructed for the data set from each sampling year separately or for both years jointly. Sampling efficiency was also evaluated by nonparametric richness estimators (Chao 1, Chao 2, Jackknife 1, Jackknife 2, and Bootstrap) available in the EstimateS 9.1.0 software (Colwell, 2006).(AU)
Assuntos
Animais , Abelhas/metabolismo , Abelhas/fisiologia , Orchidaceae/química , Orchidaceae/fisiologiaRESUMO
BACKGROUND: Nectar gain and loss are important flower transitions observed in angiosperms, and are particularly common in orchids. To understand such transitions, the availability of detailed anatomical data and species-level phylogenies are crucial. We investigated the evolution of food deception in Epidendrum, one of the largest orchid genera, using genus phylogeny to map transitions between nectar gain and loss among different clades. Associations between anatomical and histochemical changes and nectar gain and loss were examined using fresh material available from 27 species. The evolution of nectar presence/absence in Epidendrum species was investigated in a phylogenetic framework of 47 species, using one nuclear and five plastid DNA regions available from GenBank and sequenced in this study. RESULTS: The presence or absence of nectar was strongly associated with changes in the inner epidermal tissues of nectaries. Nectar-secreting species have unornamented epidermal tissue, in contrast to the unicellular trichomes found on the epidermis of food deceptive species. Bayesian tests confirmed that transitions occurred preferentially from nectar presence to nectar absence across the Epidendrum phylogeny. In addition, independent nectar loss events were found across the phylogeny, suggesting a lack of constraint for these transitions. CONCLUSIONS: Ornamented nectaries may play an important role in the deceptive pollination strategy by secreting volatile organic compounds and providing tactile stimuli to pollinators. The recurrent and apparently irreversible pattern of nectar loss in Epidendrum suggests that food deception may constitute an alternative evolutionarily stable strategy, as observed in other orchid groups.
Assuntos
Evolução Biológica , Orchidaceae/anatomia & histologia , Orchidaceae/fisiologia , Néctar de Plantas/análise , Polinização , DNA de Cloroplastos/genética , DNA de Plantas/genética , Cadeia Alimentar , Orchidaceae/genética , FilogeniaRESUMO
The adaptation and performance of orchid mycorrhizae in heavy metal-polluted soils have been poorly explored. In the present study, proteomic and metabolic approaches were used to detect physiological changes in orchid roots established in a heavy metal-polluted soil and to ascertain whether mycorrhizal fungi affect the metabolic responses of roots. Young Bipinnula fimbriata plantlets were established in control and heavy metal-polluted soils in a greenhouse. After 14 months, exudation of root organic acids, phenolics, percentage of mycorrhization, mineral content, and differential protein accumulation were measured. More root biomass, higher root colonization, and higher exudation rates of citrate, succinate, and malate were detected in roots growing in heavy metal-polluted soils. Higher accumulation of phosphorus and heavy metals was found inside mycorrhizal roots under metal stress. Under non-contaminated conditions, non-mycorrhizal root segments showed enhanced accumulation of proteins related to carbon metabolism and stress, whereas mycorrhizal root segments stimulated protein synthesis related to pathogen control, cytoskeleton modification, and sucrose metabolism. Under heavy metal stress, the proteome profile of non-mycorrhizal root segments indicates a lower induction of defense mechanisms, which, together with the stimulation of enzymes related to carotenoid biosynthesis and cell wall organization, may positively influence mycorrhizal fungi colonization. The results point to different metabolic strategies in mycorrhizal and non-mycorrhizal root segments that are exposed to heavy metal stress. The results indicate that root colonization by mycorrhizal fungi is stimulated to alleviate the negative effects of heavy metals in the orchids.
Assuntos
Metais Pesados/metabolismo , Micorrizas/fisiologia , Orchidaceae/microbiologia , Orchidaceae/fisiologia , Poluentes do Solo/metabolismo , Adaptação Fisiológica , Chile , Orchidaceae/crescimento & desenvolvimento , Proteínas de Plantas/metabolismo , Proteoma , Plântula/crescimento & desenvolvimento , Plântula/microbiologia , Plântula/fisiologiaRESUMO
Flowering plants often depend on the attraction of biotic pollinators for sexual reproduction. Consequently, the emergence and maintenance of selected floral attributes related to pollinator attraction and rewarding are driven by pollinator pressure. In this paper we explore the effect of pollinators, rainfall, temperature and air humidity on the reproduction of a Brazilian terrestrial orchid, Cranichis candida based on data of phenology, flower resources, olfactory and visual attraction cues, pollinators and breeding system. The flowers of C. candida are strongly protandrous and pollinated by workers of the social native bee Tetragonisca angustula. The bees collect labellar lipoidal substances (wax scales), which are transported to the nest. The lipoidal substance is composed of sterols, hydrocarbons and terpenes. The last presumably protects the bees and their nests against pathogens and other arthropods. C. candida sets fruits through biotic self- and cross-pollination, and spontaneously due the action of raindrops on flowers. Our results indicate that in C. candida, although rain-mediated spontaneous self-pollination happens, fructification mediated by biotic pollinations also occurs, which may result in fruit set by cross-pollination. A mixed pollination system must result in higher genetic variability when compared to species whose fruits are produced entirely by self-pollination. On the other hand, autogamy is a form of reproductive assurance, and has commonly evolved where pollination services are rare or absent.
Assuntos
Abelhas/fisiologia , Orchidaceae/fisiologia , Polinização/fisiologia , Animais , Flores/anatomia & histologia , Flores/fisiologia , Orchidaceae/anatomia & histologia , Chuva , Ceras/metabolismoRESUMO
Floral volatile organic compounds (VOCs) play important roles in plant-pollinator interactions. We investigated the reproductive ecology and floral VOCs of Zygopetalinae orchids to understand the relationship between floral scents and pollinators. We performed focal observations, phenological censuses and breeding system experiments in eight species in southeast Brazil. Floral scents were collected and analysed using SPME/GC-MS. We performed multivariate analyses to group species according to affinities of their VOCs and define compounds associated to each plant. Dichaea cogniauxiana was pollinated by weevils which use their developing ovules, while D. pendula was pollinated by the same weevils and perfume-collecting male euglossine bees. The other species were deceit-pollinated by bees. Zygopetalum crinitum was pollinated by carpenter bees, while W. warreana, Z. mackayi and Z. maxillare were bumblebee-pollinated. The latter was also pollinated by Centris confusa. Breeding system varied widely with no association to any pollinator group. Most VOCs are common to other floral scents. Zygopetalum crinitum presented an exclusive blend of VOCs, mainly composed of benzenoids. The scents of Pabstia jugosa, Promenaea xanthina and the Zygopetalum spp. were similar. The bumblebee-pollinated species have flowering periods partially overlapped, thus neither phenology nor pollinators constitute hybridization barriers among these species. Euglossines are not the only pollinators of Zygopetalinae. Different VOCs, size and lifespan of flowers are associated with distinct pollinators. A distinctive VOC bouquet may determine specialisation in carpenter bees or male euglossines within bee-pollinated flowers. Finally, visitation of deceit-pollinated flowers by perfume-collecting euglossines allows us to hypothesise how pollination by this group of bees had evolved.
Assuntos
Abelhas/fisiologia , Flores/química , Orchidaceae/química , Orchidaceae/fisiologia , Polinização , Animais , Compostos Orgânicos Voláteis/metabolismo , Gorgulhos/fisiologiaRESUMO
The Andean mountains of South America are the most species-rich biodiversity hotspot worldwide with c. 15% of the world's plant species, in only 1% of the world's land surface. Orchids are a key element of the Andean flora, and one of the most prominent components of the Neotropical epiphyte diversity, yet very little is known about their origin and diversification. We address this knowledge gap by inferring the biogeographical history and diversification dynamics of the two largest Neotropical orchid groups (Cymbidieae and Pleurothallidinae), using two unparalleled, densely sampled orchid phylogenies (including more than 400 newly generated DNA sequences), comparative phylogenetic methods, geological and biological datasets. We find that the majority of Andean orchid lineages only originated in the last 20-15 million yr. Andean lineages are derived from lowland Amazonian ancestors, with additional contributions from Central America and the Antilles. Species diversification is correlated with Andean orogeny, and multiple migrations and recolonizations across the Andes indicate that mountains do not constrain orchid dispersal over long timescales. Our study sheds new light on the timing and geography of a major Neotropical diversification, and suggests that mountain uplift promotes species diversification across all elevational zones.
Assuntos
Especiação Genética , Orchidaceae/fisiologia , Filogenia , Biodiversidade , Orchidaceae/genética , Filogeografia , América do SulRESUMO
This study aimed to develop a fuzzy mathematical model to estimate the impacts of global warming on the vitality of Laelia purpurata growing in different Brazilian environmental conditions. In order to develop the mathematical model was considered as intrinsic factors the parameters: temperature, humidity and shade conditions to determine the vitality of plants. Fuzzy model results could accurately predict the optimal conditions for cultivation of Laelia purpurata in several sites of Brazil. Based on fuzzy model results, we found that higher temperatures and lacking of properly shading can reduce the vitality of orchids. Fuzzy mathematical model could precisely detect the effect of higher temperatures causing damages on vitality of plants as a consequence of global warming.
Assuntos
Lógica Fuzzy , Aquecimento Global , Orchidaceae/fisiologia , Brasil , Produção Agrícola , Escuridão , Umidade , Orchidaceae/crescimento & desenvolvimento , Luz Solar , TemperaturaRESUMO
Abstract The aim of this study was to compare vitroplants Catasetum x apolloi grown under natural light and artificial light and different concentrations of potassium silicate, providing data on the anatomical differentiation that aids the acclimatization process of this species. Plants from in vitro seeding were used; 5 protocorms of approximately 0.5 cm were inoculated into vials with a capacity of 500 mL containing 100 mL of alternative culture medium plus potassium silicate (0.0, 0.5; 1.0 mL L–1), pH adjusted to 5.5 ± 0.5 and gelated with 4GL–1 agar before the autoclaving process. Cultures were maintained under natural light (TNE) and artificial light (TAE) for 90 days, and micromorphometric analysis was performed for polar and equatorial diameter, density and stomatal index, blade thickness in the central rib, and secondary veins. Applications in K2SiO4 alternative medium provided the following: elongation of the hypodermis, thicker mesophyll, and more prominent midrib; elipptical guard cells; formation of epistomatal chamber; and lower stomatal density and stomatal with lower equatorial and polar diameters. The conditions that favored the acclimatization were lower light intensities and lower potassium silicate doses.
Resumo O objetivo desse trabalho foi comparar vitroplantas de Catasetum x apolloi cultivadas sob luz natural e luz artificial e diferentes concentrações de silicato de potássio, fornecendo dados sobre diferenciação anatômica que auxiliem no processo de aclimatação dessa espécie. Utilizou-se plantas provenientes da semeadura in vitro, 5 protocormos de aproximadamente 0,5 cm foram inoculados em frascos com capacidade para 500 mL contendo 100 mL de meio de cultura alternativo, acrescido de silicato de potássio (0,0; 0,5; 1,0 mL L–1), pH ajustado para 5,5 ±0,5 e gelificado com 4gL–1 de ágar antes do processo de autoclavagem. As culturas foram mantidas sob luz natural (TAA) e luz artificial (TAN) por 90 dias, e feitas análises micromorfométricas (diâmetro polar e equatorial, densidade e índice estomático, espessura do limbo na nervura central e nervuras secundárias). As aplicações de K2SiO4 em meio alternativo, propiciaram: alongamento da hipoderme; mesofilo mais espesso e nervura central mais proeminente; células guardas elípticas; formação de câmaras supraestomáticas; menor densidade estomática e estômatos com menores diâmetros equatorial e polar. As condições que podem favorecer a aclimatação são menores intensidades de luz e menores doses de silicato de potássio.