Nutrient enrichment changes water transport structures of savanna woody plants

Brazilian savanna is a seasonally dry biome, highly diverse and distributed mainly on nutrient-limited soils. Interactions between water stress and nutrient availability are important evolutionary filters in these environments. Previous evidence indicated that reducing the nutritional limitation increases growth rate, optimizes water transport and decreases stomatal conductance in woody plants. However, the anatomical mechanisms that explain such responses are not well-understood. We studied the effects of long-term (20 years) nutrient addition (N, NP and P) on soil chemistry and hydraulic morphological and anatomical traits in six dominant woody savanna species. Nutrient addition and decrease in soil moisture, probably related to changes in grass cover, influenced the plant hydraulic traits at the anatomical level, namely increasing the xylem vessels’ diameter. Consequently, the specific theoretical xylem conductivity (Ktx) increased in five species under NP and P addition. Additionally, the stomatal pore index (SPI) decreased with species-specific responses regarding the intrinsic water use efficiency (iWUE). Four species had higher vulnerability to cavitation (lvul) under NP and P addition. Using community-weighted mean and structural equation modeling approaches, we observed that nutrient enrichment at the community level did not affect iWUE, while the vulnerability to cavitation (lvul) strongly increased. The Ktx and SPI were positively and negatively affected by nutrient addition, respectively, but the effects were not as strong as expected due to contrasting species responses. These changes optimized water transport with a hydraulic safety cost and reduced water loss. In comparison with responses to N addition, the greater P-limitation in Cerrado vegetation explains the inter-specific convergence in the responses of P-fertilized individuals. We showed that long-term responses to increased nutrient availability in dystrophic soils include anatomical changes in savanna woody vegetation with relevant interactions with soil-plant–atmosphere water relations.Fil: Silva Costa, Lucas. Universidade do Brasília; BrasilFil: De Moura, Clapton Olimpio. Universidade do Brasília; BrasilFil: Bucci, Sandra Janet. Universidad Nacional de la Patagonia "San Juan Bosco". Instituto de Biociencias de la Patagonia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biociencias de la Patagonia; ArgentinaFil: Sonsin-Oliveira, Julia. Universidade do Brasília; BrasilFil: Gomes, Sueli Maria. Universidade do Brasília; BrasilFil: Da Cunha Bustamante, Mercedes Maria. Universidade do Brasília; Brasi

Biodiversity of β-carboline profile of banisteriopsis caapi and ayahuasca, a plant and a brew with neuropharmacological potential

Ayahuasca is a psychoactive infusion with a large pharmacological application normally prepared with Banisteriopsis caapi, which contains the monoamine oxidase inhibitors β-carbolines, and Psichotria virids, which contains the serotonin receptor agonist N,N dimethyltryptamine (DMT). The objectives of this study were to investigate the chemical profile of B. caapi and of ayahuasca collected in various Brazilian regions. In total, 176 plant lianas, of which 159 B. caapi and 33 ayahuasca samples were analyzed. Dried liana samples were powdered, extracted with methanol, diluted, and analyzed by LC-MS/MS. Ayahuasca samples were diluted and analyzed. Mean concentrations in B. caapi were 4.79 mg/g harmine, 0.451 mg/g harmaline, and 2.18 mg/g tetrahydroharmine (THH), with a high variability among the samples (RSD from 78.9 to 170%). Native B. caapi samples showed significantly higher harmine concentrations than cultivated ones, and samples from the Federal District/Goiás had higher THH content than those collected in the State of Acre. The other Malpighiaceae samples did not contain β-carbolines, except for one D. pubipetala sample. Concentrations in ayahuasca samples ranged from 0.109 to 7.11 mg/mL harmine, 0.012 to 0.945 mg/mL harmaline, 0.09 to 3.05 mg/mL THH, and 0.10 to 3.12 mg/mL DMT. The analysis of paired ayahuasca/B. caapi confirmed that harmine is reduced to harmaline and to THH during the brew preparation. This is the largest study conducted with Malpighiaceae samples and showed a large variability in the main β-carbolines present in B. caapi. This biodiversity is a challenge for standardization of the material used in ethnopharmacological studies of B. caapi and ayahuasca

Anatomia da madeira de espécies de Cerrado sensu lato do Estado de São Paulo

O cerrado é o considerado a savana mais rica em biodiversidade do mundo, possui uma flora estimada em 7000 espécies, sendo 44% endêmicas, além de ser um dos 25 “hotspots” globais. Devido a grande importância desse bioma, esse trabalho apresenta as características anatômicas macro e microscópicas de 97 espécies arbóreas e arbustivas que ocorrem no cerrado sensu lato (s.l.), procurando identificar padrões estruturais comuns na madeira, e peculiares às espécies que ocorrem nas diferentes fitofisionomias, cerrado sensu stricto (s.s.), cerradão e zona ripária. Adicionalmente, foi caracterizada a morfologia externa da casca dessas espécies. As características anatômicas macroscópicas da madeira aliadas as da morfologia externa da casca que facilitaram a separação das espécies em uma mesma família, principalmente espécies que pertencem ao mesmo gênero foram: arranjo de vasos, padrão de parênquima axial, largura de raios (TR), estratificação de raios, presença de exsudatos e a cor interna da casca. Para as espécies de cerrado s.l. foram observadas características que podem contribuir tanto para segurança quanto para eficiência na condução hídrica, como: alta ocorrência de vasos múltiplos e frequência de vasos por mm², pontoações intervasculares alternas pequenas, pontoações guarnecidas; placas de perfuração simples. O índice de vulnerabilidade foi de 1,6 e de mesomorfia 600. Apesar da maioria das características anatômicas das espécies do cerrado s.l. se enquadram nas tendências ecológicas para espécies que ocorrem em terras baixas dos trópicos, as espécies que ocorrem nas diferentes fitofisionomias possuem características anatômicas que mostram estratégias particulares para sobrevivência das mesmas. Quando comparando as fitofisionomias, de uma maneira geral, os espécimes da zona ripária apresentaram vasos de maior diâmetro...The cerrado is considered the richest savanna in biodiversity in the world, its flora has about 7000 species, being 44% endemic, besides being one of the 25 global hotspots. Due to the great importance of this biome, this paper shows macro and microscopic wood anatomical features of 97 arboreal and shrubby species which occur in cerrado sensu lato, aiming to verify the common structural patterns in the wood, and peculiars to the species that occur in three different physiognomies, cerrado sensu stricto (s.s.), cerradão and riparian zone. Additionally, the external bark morphology of these species was characterized. Macroscopic wood features allied to bark surface features which facilitate separation of species within a family and, mostly species from the same genus were: vessel arrangement, axial parenchyma pattern, ray width (TR), storied rays, presence of exudates and bark internal colour. For cerrado s.l. species we observed anatomic features that may contribute to both safety in water flow and efficiency, such as: high incidence of multiple vessels and high vessel frequency per mm², small intervessel pits alternate, vestured pits, simple perforation plates. The vulnerability and mesomorphy index were 1.6 and 600, respectively. Despite of the majority of cerrado s.l. species anatomical features were framed in the ecological trends for species which occur in tropical lowlands, the specimens which occur in the different physiognomies have anatomical features that show particular strategies for survival in each physiognomy. When comparing the physiognomies, in a general way, riparian zone specimens have larger vessels, low frequency per mm² and larger intervessel pits diameter, what indicates better efficiency in conduction, while cerrado s.s. specimens were the opposite and showed low vulnerability and mesomorphy index, demonstrating greater safety under conditions... (Complete abstract click electronic access below)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Variações estruturais do lenho de espécies de cerrado do estado de São Paulo

Informações sobre características anatômicas do xilema secundário de espécies de cerrado são escassas, porém de grande importância, uma vez que o cerrado é influenciado por fatores ambientais diversos e as espécies que aí se encontram apresentam características morfológicas externas e internas peculiares. Estes estudos permitem compreender a influência dos fatores ambientais nas características estruturais do lenho. O presente trabalho tem por objetivo verificar os padrões e as variações estruturais do lenho, bem como determinar possíveis características de valor taxonômico e ecológico de 48 espécies arbustivas e arbóreas, incluídas em 27 famílias, ocorrentes em área de cerrado localizada no município de Pratânia, região centro-oeste do estado de São Paulo, Brasil (23º 02’ 55,5” S e 48º 31’ 26,1” W). Foram amostrados três espécimes para cada espécie e de cada espécime foi coletado o ramo mais desenvolvido da copa. Destes ramos foram retirados discos que tiveram sua porção basal polida para as análises macroscópicas qualitativas e para as análises microscópicas quali e quantitativas das características anatômicas do lenho. Verificou-se, destas análises, a presença de células perfuradas de raio (CPR) em sete espécies e, desta forma, decidiu-se por coletar também as raízes destas espécies para averiguar a presença das CPR no lenho destas. As raízes foram coletadas a uma profundidade de aproximadamente 30 cm. Nas amostras das raízes foram realizadas análises qualitativas e quantitativas das CPR. No lenho dos ramos caulinares das espécies foram caracterizados os marcadores de crescimento, bem como foi descrita a estrutura das camadas de crescimento. Os seguintes padrões foram observados: camadas de crescimento bem definidas (61% das espécies), mal definidas (33%), e ausentes (6%); porosidade difusa (94%), anel semi-poroso...Information about the secondary xylem anatomy of cerrado species are scarce, but of great importance, since cerrado is influenced by the environmental factors its species show peculiars external and internal morphologic characteristics. These studies allow a better comprehension of the environmental factors influence on the structural characteristics of the wood. These studies aims to verify patterns and the structural variations of the secondary xylem, and also to determine the characteristics of ecological and taxonomic value of 48 shrubby and arboreal species, from 27 families of the Pratânia’s cerrado region, located in the west central part of the state of São Paulo, Brazil (23º 02’ 55, 5” S e 48º 31’ 26,1” W). In these studies we obtained three specimens from each species. From each specimen we collected the most developed branches of the treetops. From the collected branches, samples were taken and its basal portion polished for the qualitative macroscopic analysis and also for the qualitative and quantitative microscopic analysis of the secondary xylem characteristics. From these analyses, we verified the presence of perforated ray cells (PRC) in seven species and also we decided to collect roots to verify the presence of PRC’s in the secondary xylem of these species. The roots were collected to a depth of 30 cm, and on the samples qualitative and quantitative analyses were performed on the PRC. On the secondary xylem of branches we characterized the growth ring markers and described the structure of the growth layer. The following patterns were observed: growth rings well defined (61%), poorly defined (33%), absent (6%); diffuse-porous (94%) and semi-ring-porous (6%); without vessel arrangement (84%), in radial pattern (10%) and in tangential bands (6%); solitary and multiple vessels (94%) and exclusively solitary (6%); simple perforation plate (90%) ...(Complete abstract click electronic access below)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Growth rings in cerrado woody species: occurrence and anatomical markers

Growth ring occurrence was investigated in 48 representative species of cerrado in the state of São Paulo, Brazil. We characterized growth ring markers and described the growth layer structure of the basal portion of the most developed stem branches in woody plants. Growth rings were poorly defined in 33%, well defined in 61% and not discernable in 6% of the species studied. Various anatomical features were used as growth markers, such as: thick-walled latewood fibres; radially flattened latewood fibres; fibre zones; distended rays; marginal bands of axial parenchyma; marginal lines of parenchyma; and closeness of the narrow bands of scalariform parenchyma. In a single species, different growth ring markers often occurred together. Within growth layers, variations in the anatomical features were observed. Variations in the axial parenchyma distribution within growth rings in Vochysia cinnamomea, Qualea multiflora, V. rufa and V. tucanorum, wood are here reported for the first time. Variation in the distance of the axial parenchyma in narrow bands along the rays within growth layers in Annona coriacea, A. crassiflora, Diospyrus hispida and Roupala montana wood is also reported. Phenology and habit of the studied species were important aspects related to both growth ring presence and distinctness as well as to the anatomical features' variations within growth layers

Perforated ray cells in the wood of roots and branches of cerrado species from Brazil

Perforated ray cells (PRCs) are recorded here for the first time in the roots and branches of Schefflera vinosa, Caryocar brasiliense, Acosmium subelegans, Byrsonima basiloba, B. coccolobifolia, B. verbascifolia and Alibertia concolor which occur in Pratania's cerrado (SP, Brazil). PRCs are larger than normal ray cells, occurring isolated or in groups of two or more in the same ray, and are present predominantly in the uniseriate portion of multiseriate rays in all species studied. In the roots and branches, the types of perforation plates (PP) of the PRCs are similar to those of the vessel elements (VE) in most species, with the exception of the branches of Schefflera vinosa and the branches and roots of Caryocar brasiliense. The diameter of the PRC plates was greater in the roots than in the branches, but the differences were only statistically significant in Schefflera vinosa, Byrsonima basiloba and B. verbascifolia. In a general way the PRC plates were greater in diameter than the VE plates in both roots and branches of most species.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Functional trade-offs in volume allocation to xylem cell types in 75 species from the Brazilian savanna Cerrado

Background and Aims Xylem is a crucial tissue for plant survival, performing the functions of water transport, mechanical support and storage. Functional trade-offs are a result of the different assemblages of xylem cell types within a certain wood volume. We assessed how the volume allocated to different xylem cell types can be associated with wood functional trade-offs (hydraulics, mechanical and storage) in species from the Cerrado, the Brazilian savanna. We also assessed the xylem anatomical characters linked to wood density across species. Methods We analysed cross-sections of branches collected from 75 woody species belonging to 42 angiosperm families from the Cerrado. We estimated the wood volume fraction allocated to different cell types and performed measurements of vessel diameter and wood density. Key Results The largest volume of wood is allocated to fibres (0.47), followed by parenchyma (0.33) and vessels (0.20). Wood density is positively correlated to cell wall (fibre and vessel wall), and negatively to the fractions of fibre lumen and gelatinous fibres. We observed a trade-off between hydraulics (vessel diameter) and mechanics (cell wall fraction), and between mechanics and storage (parenchyma fraction). The expected positive functional relationships between hydraulics (vessel diameter) and water and carbohydrate storage (parenchyma and fibre lumen fractions) were not detected, though larger vessels are linked to a larger wood volume allocated to gelatinous fibres. Conclusions Woody species from the Cerrado show evidence of functional trade-offs between water transport, mechanical support and storage. Gelatinous fibres might be potentially linked to water storage and release by their positive relationship to increased vessel diameter, thus replacing the functional role of parenchyma and fibre lumen cells. Species can profit from the increased mechanical strength under tension provided by the presence of gelatinous fibres, avoiding expensive investments in high wood density