Abstract Forest fragments are susceptible to environmental shifts and this demands high phenotypic plasticity of the species growing in these areas. In this context, the objective of the present work was to study the phenotypic plasticity of copaíba (Copaifera langsdorffii Desf.) based on morphological and anatomical metrics of the leaflets of plants from six forest fragments. The leaflets of C. langsdorffii individuals of the different fragments did not show qualitative differences, nonetheless, they demonstrated quantitative plasticity. Stomatal density (p = 0.017), specific leaf area (p = 0.009), palisade parenchyma (p = 0.008) and relative water content (p = 0.002), indicated a high luminous, water and nutritional influence on the development of leaflets. Based on the dry mass of the leaflets and the thickness of the palisade parenchyma, the principal component analysis explained 57.43% of the differences found between the variables. The data presented here provides evidence of the phenotypic plasticity of C. langsdorffii which, although occurring in similar soils, showed significant quantitative differences in its morphoanatomical characters.

Resumo Um dos principais métodos para estudo de anatomia das plantas é a análise de cortes finos e transparentes, submetidos à coloração. Corantes sintéticos tradicionalmente utilizados em estudos anatômicos podem ser caros e produzidos por empresas específicas. O uso alternativo de corantes têxteis industriais, pode representar tanto uma substituição acessível economicamente quanto uma opção ecologicamente viável de uso desses corantes. Neste estudo foram avaliados 22 tipos de corantes têxteis. Cortes transversais, longitudinais e paradérmicos de órgãos de plantas, obtidos pela técnica de corte à mão livre foram submetidos às soluções hidroalcoólicas (0 a 100%) de corantes têxteis adquiridos em mercados locais. A solução hidroalcoólica a 50% dos corantes mostrou maior eficiência no contraste dos tecidos, maior solubilidade do pó corante e melhor interação das soluções com os tecidos vegetais. A maioria dos corantes testados mostraram resultados satisfatórios. A parede celular, especialmente a lignificada, mostrou maior eficiência de coloração. Análises de ancoragem molecular utilizando modelos de celulose e lignina mostraram os prováveis mecanismos de associação e seletividade dos corantes com os componentes da parede celular. A abordagem aqui realizada pode ser útil em aulas práticas conjugadas de anatomia vegetal, química e / ou bioquímica, tanto no ensino médio quanto no nível de graduação.

Abstract One of the main methods for plant anatomy study is the analysis of thin, transparent, and stained tissue sections. Synthetic dyes traditionally used in anatomical studies might be expensive and produced by specific companies. In contrast, the use of alternative industrial dyes can both represent an inexpensive substitute as well as an environmentally friendly option for conducting plant anatomy studies. In this study, a set of 22 textile dyes was evaluated. Transversal-, longitudinal, and paradermal sections of plant organs obtained using the freehand cutting technique were stained using hydroalcoholic solution (0 to 100%) of textile dyes purchased from a local market. Dyes mixed with 50% hydroalcoholic solution showed higher efficiency in tissue contrast, allowing greater solubility of dye powder and better solution interaction with the plant tissues. Most of the tested dyes showed satisfactory staining results. Cell wall, especially lignified one, showed higher staining efficiency. Computational docking analysis and molecular models of cellulose and lignin showed the probable association mechanisms and dye selectivity to cell wall constituents. Our findings suggest that the developed method can be useful in mixed practical classes of plant anatomy, chemistry, and/or biochemistry, both at high school as well as undergraduate levels.

Resumo Orchidaceae é a maior família de plantas vasculares, e constitui-se num grupo sob intensa ameaça devido à ação antrópica. Cattleya caulescens e C. endsfeldzii são espécies rupícolas endêmicas de Minas Gerais, Brasil, e figuram em listas vermelhas de espécies ameaçadas de âmbito estadual e nacional. Sendo assim, foram conduzidos estudos morfoanatômicos com o objetivo de incrementar os conhecimentos desses táxons, tendo em vista o potencial que esses estudos representam no manejo de espécies. Cattleya caulescens e C. endsfeldzii apresentam fortes similaridades morfoanatômicas, o que apoia estudos anteriores, que incluem ambas numa mesma seção do gênero. Diversas características anatômicas aqui descritas (epiderme unisseriada, folha hipoestomática, grandes campos de pontuações primárias no parênquima clorofiliano e a anatomia da raiz) são comuns a várias outras espécies de Orchidaceae. Os caracteres xeromórficos observados estão relacionados às condições edafoclimáticas, já que ocorrem em substrato rochoso, em constante exposição aos raios solares e restrição hídrica severa durante a maior parte do ano. Este trabalho contribui para se ampliar o conhecimento do gênero Cattleya e auxiliar na delimitação taxonômica destas espécies ameaçadas, ocorrentes em áreas de intensa atividade antrópica.

Abstract Orchidaceae is the largest family of vascular plants and is a group under intense threat due to anthropic activities. Cattleya caulescens and C. endsfeldzii are endemic rupiculous species of Minas Gerais state, Brazil, and listed on Red Lists of endangered species at state and national levels. We conducted morphoanatomical studies with the vegetative organs of the two species, with the objective of increasing knowledge of these taxa, considering the potential that these studies represent in the management of species. Cattleya caulescens and C. endsfeldzii show strong morphoanatomical similarities, which corroborates with previous studies that include both species in the same section of the genus. Many anatomical features described here (presence of single-layered epidermis, stomata only on the abaxial side of the leaf, large primary pit fields in the chlorophyll parenchyma and root anatomy) are common to several other species of Orchidaceae. The xeromorphic features observed in C. caulescens and C. endsfeldzii are related to edaphoclimatic conditions, since they grow on rocky substrate, in constant exposure to solar light and severe water restriction during most of the year. This work contributes to increase the knowledge about Cattleya genus and to support in the taxonomic delimitation of these endangered species occurring in areas of intense antropic activity.

Resumo Coléteres são estruturas secretoras que produzem uma substância pegajosa, constituída por uma mistura de mucilagens, proteínas, terpenos, substâncias pécticas e até alcaloides, que lubrifica e protege o meristema apical. Vários tipos de coléteres têm sido descritos e apresentam valor taxonômico em muitas famílias botânicas. Em Myrtaceae, a descrição de coléteres é recente apresentando três novos tipos morfológicos (cônico, euriforme e petalóide) que diferem dos já descritos para outras eudicotiledôneas. Neste trabalho, são descritos os tipos morfológicos de coléteres em seis espécies de três gêneros pertencentes à tribo Myrteae da subfamília Myrtoideae do Cerrado brasileiro. As amostras foram fixadas para microscopia de luz e eletrônica de varredura. Testes histoquímicos foram realizados em material fresco e em incluído em metacrilato. Foram observados coléteres cônico e euriforme, que não diferiram nem morfoanatomicamente nem quanto à natureza de secreção, daqueles já descritos para espécies de Myrtoideae, o que pode indicar seu uso potencial para fins taxonômicos. Considerando a hipótese de que as linhagens múltiplas de frutos carnosos evoluíram de forma independente na tribo Myrteae, nossos resultados indicam a relevância de estudos adicionais para se reconhecer o padrão de distribuição de coléteres em Myrtaceae.

Abstract Colleters are secretory structures that produce a sticky substance, consisting of a mixture of mucilage, proteins, terpenes, pectic substances and even alkaloids, which lubricates and protects the shoot apical meristem. Several colleter types have been described and have taxonomic value in many botanical families. In Myrtaceae, the colleters description is recent and presents three new morphological types (conic, euryform and petaloid) that differ those already described for other eudicots. In this work, we report the colleters morphological types in six species of three genera belonging to the Myrteae tribe of Myrtoideae from the Brazilian Cerrado. The samples were fixed for light and scanning electron microscopy. Histochemical tests were carried out on the fresh and methacrylate-embedded material. The conic and euryform colleters from Myrtoideae species of the Cerrado did not differ either morphologically nor as to the secretion nature from those described for Myrtoideae species from others biomes, which may indicate their potential use for taxonomic purposes. Considering the hypothesis that the multiple fleshy-fruit lineages have evolved independently in Myrteae tribe, our results indicate the relevance of additional studies in order to recognize the pattern of distribution of colleters in Myrtaceae.

Anatomical and histochemical investigations of Sphagneticola trilobata (L.) Pruski, Asteraceae, secretory structures in leaves and stems and the seasonal variation of essential oils were carried out. Histochemical techniques enabled the specific location of the essential oil accumulation in the internal (canals) and external structures (trichomes). Histochemical analysis showed that the secretory trichomes produced steroids. The highest yield was obtained from plants collected in winter, when it was registered low temperature and precipitation. The essential oil was characterized by high percentage of hydrocarbon sesquiterpenes, hydrocarbon monoterpenes and low levels of oxygenated sesquiterpenes. The major components were germacrene D (11.9-35.8%), α-phellandrene (1.4-28.5%), α-pinene (7.3-23.8%), E-caryophyllene (4.6-19.0%), bicyclogermacrene (6.0-17.0%), limonene (1.8-15.1%) and α-humulene (4.0-11.6%). The percentage of most of the individual constituents present in S. trilobata essential oil changed significantly during the months.