Christopher William Fagg

Diversity, floristic and structural patterns of cerrado vegetation in Central Brazil

The cerrado has been identified as one of the richest and most threatened biomes of the world, but few phytogeographical studies have been undertaken in the region. A total of 70 land systems based on climate, landscape and soils have been identified in the region, but it remains to be seen if the distribution and structure of the plant communities support these divisions. The aim of this work was to compare the floristic and structural similarity of cerrado sensu stricto within and between three physiographic units, named Pratinha, Veadeiros and São Francisco, which contain six land systems in central Brazil and cover 10 degrees of latitude and five degrees of longitude. The woody vegetation of 15 selected sites of the cerrado sensu stricto physiognomy was surveyed under a standardized methodology. The number of species per site varied from 55 to 97, with most sites having around 60 to 70 species, and Shannon´s diversity indices ranged from 3.44 to 3.73, with most sites around 3.5 suggesting high alpha diversity. Sørensen´s floristic similarity index was high, with all Figures above 0.5 between the sites in the same land system in each physiographic unit but low between sites in different land systems in the Veadeiros. Czekanowski similarity indices were lower than Sørensen’s in the comparisons due to a high structural differentiation between the sites. There is a large overlap in species occurrence in the sites but the size of their populations is very different at each site. Therefore, the high beta diversity is mostly due to differences in abundance of species between sites. The sites were separated by physiographic units, considering the first three divisions of TWINSPAN classification. The first axis of DCA ordination showed a gradient going from the cerrado on deep soils in Pratinha, through to those on sandy soils in São Francisco and ending on the shallower soils of the Veadeiros. Land systems conformed well with the floristic and structural variations of the vegetation, indicating their potential use in designing a network of conservation areas in the cerrado region and as a basis for decision-making on management.

Acacia: The case against moving the type to Australia

Recent studies have shown that Acacia is polyphyletic and must be split into five genera. Proposal 1584 would retypify Acacia : the type of the Australian taxon A. penninervis would be conserved over the current lectotype ( A. scorpioides ) of an African taxon. We disagree with the recommendation of the Spermatophyte Committee to endorse this proposal. Contrary to Article 14.12 of the ICBN, no detailed case against conservation was presented in Proposal 1584. We maintain that there are strong arguments against conservation, such as the large number of countries that would be affected, the economic importance of the extra-Australian species, and the economic burden placed on developing countries. Acceptance of this proposal would also violate the guidelines for conservation which clearly state that the principle of priority should prevail when conservation for one part of the world would create disadvantageous change in another part of the world.

Bitter plants used as substitute of Cinchona spp. (quina) in Brazilian traditional medicine.

ETHNOPHARMACOLOGICAL RELEVANCE Bitter tasting plant species are used as tonics and have been previously used to treat intermittent fevers in Brazil, the principal symptom of malaria. Many of these species were named quina and were used as substitutes of Cinchona spp., the source of quinine. AIM OF THE STUDY To present data on these bitter species named quina and to discuss their potential as sources of bioactive substances. MATERIALS AND METHODS Data about the plants were obtained from a survey of the literature and documents written by early naturalists and clinical doctors living in the 18th and 19th centuries in Brazil. Correlated pharmacological studies were obtained from different scientific databases. RESULTS A total of 29 species were recorded. The largest number of species belonged to the Rubiaceae family (14), being Remijia ferruginea (A. St.-Hil) DC. the most representative. Strychnos pseudoquina A. St.-Hil. (Loganiaceae), Hortia brasiliana Vand. ex DC. (Rutaceae) and Solanum pseudoquina A. St.-Hil. (Solanaceae) were also frequently mentioned in the historical bibliography. Pharmacological studies have shown the presence of bitter bioactive substances useful to treat digestive disorders and/or with antimalarial activities, in all of the recorded botanic families. CONCLUSION This study shows that several bitter species named quina were used in the past as substitute of Cinchona spp. and studying these plants can lead to the development of new products.

Desenvolvimento inicial e partição de biomassa de Brosimum rubescens Taub. (Moraceae) sob diferentes níveis de sombreamento

Monodominant forests of Brosimum rubescens Taub. (Moraceae) occur at the Cerrado/Amazonia boundary and are threatened by logging. Light is considered an important determinant for monodominance in forests, so the aim of this study was to analyze initial growth at shading levels of 0, 30, 50, 70 and 90% in the nursery, in a forest gap, and also at a closed canopy site. Photosynthesis was measured in seedlings at three shading levels. Seedlings under a closed canopy showed lower relative growth rates in comparison to seedlings growing in a nearby gap. At 21 months of age, the highest total dry mass of 9.46 g was measured at 50% shading. This represents a biomass accumulation of 144% over that found at 90% shading. For all treatments in every assessment the partitioning was dry matter of roots > leaves > stems. The lowest maximum photosynthesis rate (Amax= 3.46 µmol m-2 s-1) was recorded at 90% shading and the highest (Amax= 7.89 µmol m-2 s-1) was recorded at 30% shading. Gaps seem to play an important role in maintaining monodominance since B. rubescens showed some plasticity regarding light conditions and grew better at intermediate shading levels.

Desenvolvimento inicial e repartição de biomassa de Amburana cearensis (Allemao) A.C. Smith, em diferentes condições de sombreamento

Amburana cearensis has a wide geographical distribution throughout the seasonal forests and transition zones forest/savanna (Cerrado) and forest/dry seasonal forests (Caatinga) in the North, Northeast and Central Brazil. It is under threat due to over exploitation of its valuable timber and the massive convertion of the forests into agricultural land. Little is known on the growth and biomass allocation of the seasonal forests species. The hypothesis is that those species show some degree of phenotipic plasticity due to the strong seasonal light gradient found under natural conditions, in addition to those variations usually found under the canopy. This study can contribute to a better understanding of the functioning of the seasonal forest ecosystems and also to the silviculture of this species. The objective of this work was to study the growth and biomass allocation of seedlings of A. cearensis under full sun and three shading levels, in nursery conditions. The shading levels averaged 0%, 50%, 70% and 90% of the full sunlight. The experimental design was randomized with 25 replicates per treatment. Height, stem base diameter, number of leaves and leaflets were monitored from four months till 16 months of age, and dry matter was analyzed at 19 months of age. Biomass accumulation was affected by the shading levels. The total biomass was higher under full sunlight (10,55g), followed by 50%, and 70% shading, while the lowest average was found under 90% (4,59g). Eighty percent of total biomass was found in the roots for the unshaded plants. This pattern of biomass partioning predominantly to roots occurred in all treatments. The initial development under nursery conditions indicates that this species could be introduced during the early stages of a program to reclaim degraded seasonal forests, as well as used in plantation trials.

Extracts of Morus nigra L. Leaves Standardized in Chlorogenic Acid, Rutin and Isoquercitrin: Tyrosinase Inhibition and Cytotoxicity

Melanogenesis is a process responsible for melanin production, which is stored in melanocytes containing tyrosinase. Inhibition of this enzyme is a target in the cosmetics industry, since it controls undesirable skin conditions such as hyperpigmentation due to the overproduction of melanin. Species of the Morus genus are known for the beneficial uses offered in different parts of its plants, including tyrosinase inhibition. Thus, this project aimed to study the inhibitory activity of tyrosinase by extracts from Morus nigra leaves as well as the characterization of its chromatographic profile and cytotoxicity in order to become a new therapeutic option from a natural source. M. nigra leaves were collected, pulverized, equally divided into five batches and the standardized extract was obtained by passive maceration. There was no significant difference between batches for total solids content, yield and moisture content, which shows good reproducibility of the extraction process. Tyrosinase enzymatic activity was determined for each batch, providing the percentage of enzyme inhibition and IC50 values obtained by constructing dose-response curves and compared to kojic acid, a well-known tyrosinase inhibitor. High inhibition of tyrosinase activity was observed (above 90% at 15.625 μg/mL). The obtained IC50 values ranged from 5.00 μg/mL ± 0.23 to 8.49 μg/mL ± 0.59 and were compared to kojic acid (3.37 μg/mL ± 0.65). High Performance Liquid Chromatography analysis revealed the presence of chlorogenic acid, rutin and, its major compound, isoquercitrin. The chromatographic method employed was validated according to ICH guidelines and the extract was standardized using these polyphenols as markers. Cytotoxicity, assessed by MTT assay, was not observed on murine melanomas, human keratinocytes and mouse fibroblasts in tyrosinase IC50 values. This study demonstrated the potential of M. nigra leaf extract as a promising whitening agent of natural source against skin hyperpigmentation.

Useful Brazilian plants listed in the manuscripts and publications of the Scottish medic and naturalist George Gardner (1812-1849).

ETHNOPHARMACOLOGICAL RELEVANCE Information regarding the beneficial use of native Brazilian plants was compiled by a number of European naturalists in the 19th century. The Scottish surgeon botanist George Gardner (1812-1849) was one such naturalist; however, the useful plants recorded in his manuscripts have not yet been studied in depth. AIM OF THE STUDY To present data recorded by Gardner in his manuscript Catalogue of Brazilian Plants regarding the use of native plants by Brazilian people and evaluate the extent to which they have been explored. MATERIALS AND METHODS Data on useful plants were obtained from Gardner׳s manuscript Catalogue of Brazilian Plants deposited in the Archives of the Royal Botanic Gardens, Kew, UK. The identification of each plant was determined and/or updated by consulting the preserved botanical collections of Gardner deposited in the Herbarium of the Royal Botanic Gardens, Kew (hereafter K), and expert determinations in other herbaria where duplicates are held. Correlated pharmacological studies for each plant were obtained from the PubMed database. Information recorded in Gardner׳s diary and previously published elsewhere complemented these data. RESULTS A total of 63 useful plants was recorded from the Catalogue and a further 30 from Gardner׳s book Travels in the Interior of Brazil (Gardner, 1846). Of the recorded names in the Catalogue, 46 (73%) could be identified to species by consulting specimens collected by Gardner and held at Kew. Thirty-six different traditional uses were registered for the identified plants, the most common being as febrifuges, to treat venereal complaints and as purgatives. Fewer than 50% of these species have been the focus of published pharmacological studies, yet for those which have been thus investigated, the efficacies reported by Gardner were confirmed. CONCLUSION The data recorded by Gardner represent a rich, relatively unexplored source of information regarding the traditional uses of Brazilian plants which merits further investigation.

Avaliação temporal da regeneração natural em uma floresta estacional semidecídua secundária, em Pirenópolis, Goiás

The natural regeneration in forest environments is dynamic, variable in space and time and it is in the development cycle of forests. In seasonal tropical forests, due to seasonal climatic changes, natural regeneration depends mainly on availability of soil moisture, which affects patterns of seed production and germination, survival and development of seedling as well. The objective of this study was to analyze the dynamics of natural regeneration in a seasonal semideciduous secondary forest in Pirenopolis, Goias, Brazil, by analyzing the changes in floristic composition of seedlings and small trees over time and relating them to environmental factors of plots in the study area by using Canonical Correspondence Analysis (CCA). The results indicated that seedlings were more dynamic than small trees mainly because of climate. This occurred because of the greater susceptibility of the seedling to soil water stress and the increase of solar radiation and temperature in the dry season. It was found a high floristic similarity (± 50%) among population of natural regeneration and the tree community, indicating an advanced stage of natural regeneration of the forest, with Diversity Index higher than 3.0 nats.indv-1. Canonical Correspondence Analysis grouped the species according to the environmental gradient of moisture and shade versus soil cover, placing near to each other, species of humid environments versus species of typical cerrado dry environments.

Florestas estacionais e áreas de ecótono no estado do Tocantins, Brasil: parâmetros estruturais, classificação das fitofisionomias florestais e subsídios para conservação

O objetivo deste estudo foi descrever a riqueza, estrutura e diversidade de especies arboreas em areas de Floresta Estacional e ecotono (Floresta Estacional/Floresta Ombrofila) no estado do Tocantins, buscando subsidios para a conservacao, manejo florestal, compensacao de reserva legal e recuperacao ambiental, alem de discutir as identidades fitogeograficas em comparacao com outras florestas do Brasil. Em 18 bacias hidrograficas, conduziu-se amostragem da vegetacao arborea (DAP > 5 cm) de 22 areas (amostras) por meio do inventario de 477 parcelas de 400 m². Foram elaboradas analises de classificacao pelo metodo TWINSPAN, em duas escalas distintas. A primeira avaliou a diversidade beta entre as parcelas amostradas no estado do Tocantins e a segunda buscou analisar a similaridade das florestas do Tocantins em relacao a outras florestas do bioma Cerrado e suas areas de tensao ecologica. As florestas amostradas apresentaram ampla variacao em termos de riqueza (33 a 243 especies), densidade (486 a 1.179 ind.ha-1), area basal (14,04 e 37,49 m².ha-1), indices de diversidade (H´ = 2,75 a 4,59) e de equabilidade (J´= 0,72 a 0,86). As analises de classificacao convergiram para resultados comuns, identificando quatro ambientes dissimilares em termos floristicos e estruturais no estado do Tocantins: Floresta Estacional Decidual, Floresta Estacional Semidecidual, ecotono Floresta Estacional Semidecidual/Floresta Ombrofila e ecotono Floresta Estacional Decidual/Floresta Ombrofila. A fim de manter a diversidade de plantas e de ambientes na regiao de transicao Floresta Amazonica e Cerrado, sugere-se que o processo de criacao de unidades de conservacao no estado do Tocantins deva ser intensificado e tenha como base para selecao das areas criterios biogeograficos.

Avaliação do plantio homogêneo de mogno, swietenia macrophyllaking, em comparação com o plantio consorciado com eucalyptusurophylla s. t. blake, após 40 meses de idade

In the Amazon, plantations of mahogany have been limited by attacks of Hypsiphylla grandella Zeller. On the other hand, urban plantings in Brasilia have developed well. The objective of this work was to observe the development of mahogany in homogenous or in mixed stands with eucalypts planted in the Agua Limpa farm at the University of Brasilia - Federal District. The variables height, at 7, 12, 15, 24, 28, 36 and 40 months of age, and diameter, at 7, 24, 28, 36 and 40 months were measured. A split-plot entirely randomized design was used, the treatments being the plot and time the sub-plot. The average height of mahogan 40 months after planting in the mixed stands was of 2.28 m, whereas in homogenous stands it was 3.45 m and the maximum heights recorded were 4.15 m and 5.17 m respectively. The average diameter was also larger in the homogenous stand, with 6.92 cm compared to 4.08 cm for the mixed stands. Mortality was around 20% under both conditions. Attacks by H. grandella larvae was less in mixed stands, indicating that the eucalypts may function as a barrier, reducing the attack.